WO2015175130A1 - Blue luminescent compound and diastereomers thereof - Google Patents

Abstract

There is provided a composition which is capable of being separated into diastereomeric pairs of enantiomers. The compound has (Formula I) In Formula I: Ar^' can be aryl or deuterated aryl; R¹ can be H, D, alkyl, silyl, aryl, or a deuterated analog thereof; R² is different from R¹ and can be H, D, alkyl, silyl, aryl, or a deuterated analog thereof, with the proviso that only one of R¹ and R² is H or D; R³ is the same or different at each occurrence and can be D, alkyl, silyl, aryl, or a deuterated analog thereof; a is an integer from 0-3; and b is an integer from 0-4.

Description

TITLE

BLUE LUMINESCENT COMPOUND AND DIASTEREOMERS THEREOF BACKGROUND INFORMATION

Field of the Disclosure

This disclosure relates in general to compositions of diastereomeric pairs of enantiomers of blue luminescent compounds and their use in electronic devices.

Description of the Related Art

Organic electronic devices that emit light, such as light-emitting diodes that make up displays, are present in many different kinds of electronic equipment. In all such devices, an organic active layer is sandwiched between two electrical contact layers. At least one of the electrical contact layers is light-transmitting so that light can pass through the electrical contact layer. The organic active layer emits light through the light-transmitting electrical contact layer upon application of electricity across the electrical contact layers.

It is well known to use organic electroluminescent compounds as the active component in light-emitting diodes. Simple organic molecules, such as anthracene, thiadiazole derivatives, and coumarin derivatives are known to show electroluminescence. Metal complexes, particularly iridium and platinum complexes are also known to show electroluminescence. In some cases these small molecule compounds are present as a dopant in a host material to improve processing and/or electronic properties.

There is a continuing need for new luminescent compounds.

SUMMARY

There is provided a composition capable of being separated into n diastereomeric pairs of enantiomers, the composition having Formula I Formula I

wherein:

Ar' is selected from the group consisting of aryl and deuterated aryl R¹ is selected from the group consisting of H, D, alkyl, silyl, aryl, and deuterated analogs thereof;

R² is different from R¹ and is selected from the group consisting of

H, D, alkyl, silyl, aryl, and deuterated analogs thereof, with the proviso that no more than one of R¹ and R² is H or D; R³ is the same or different at each occurrence and is selected from the group consisting of D, alkyl, silyl, aryl, and deuterated analogs thereof;

a is an integer from 0-3;

b is an integer from 0-4.

There is also provided a composition consisting essentially of n diastereomeric pairs of enantiomers of Formula I, where n is 1 , 2, or 3.

There is also provided an organic electronic device comprising a first electrical contact, a second electrical contact and a photoactive layer therebetween, the photoactive layer comprising the composition of Formula I.

There is also provided an organic electronic device comprising a first electrical contact, a second electrical contact and a photoactive layer therebetween, the photoactive layer comprising n diastereomeric pairs of enantiomers having Formula I.

The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as defined in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated in the accompanying figures to improve understanding of concepts as presented herein.

FIG. 1 includes an illustration of an organic light-emitting device.

FIG. 2 includes another illustration of an organic light-emitting device.

Skilled artisans appreciate that objects in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the objects in the figures may be exaggerated relative to other objects to help to improve understanding of embodiments.

DETAILED DESCRIPTION

Many aspects and embodiments have been described above and are merely exemplary and not limiting. After reading this specification, skilled artisans appreciate that other aspects and embodiments are possible without departing from the scope of the invention.

Other features and benefits of any one or more of the embodiments will be apparent from the following detailed description, and from the claims. The detailed description first addresses Definitions and

Clarification of Terms followed by Diastereomers of Formula I,

Composition Having Formula I, Synthesis, Devices, and finally Examples. 1 . Definitions and Clarification of Terms

Before addressing details of embodiments described below, some terms are defined or clarified.

The term "alkyl" is intended to mean a group derived from an aliphatic hydrocarbon and includes a linear, a branched, or a cyclic group. In some embodiments, an alkyl has from 1 -20 carbon atoms.

The term "aromatic compound" is intended to mean an organic compound comprising at least one unsaturated cyclic group having delocalized pi electrons. The term "aryl" is intended to mean a group derived from an aromatic hydrocarbon having one point of attachment. The term includes groups which have a single ring and those which have multiple rings which can be joined by a single bond or fused together. The term is intended to include both hydrocarbon aryls, having only carbon in the ring structure, and heteroaryls. The term "alkylaryl" is intended to mean an aryl group having one or more alkyl substituents. In some embodiments, a

hydrocarbon aryl has 6-60 ring carbons. In some embodiments, a heteroaryl has 3-60 ring carbons.

The term "charge transport," when referring to a layer, material, member, or structure is intended to mean such layer, material, member, or structure facilitates migration of such charge through the thickness of such layer, material, member, or structure with relative efficiency and small loss of charge. Hole transport materials facilitate positive charge; electron transport materials facilitate negative charge. Although light-emitting materials may also have some charge transport properties, the term "charge transport layer, material, member, or structure" is not intended to include a layer, material, member, or structure whose primary function is light emission.

The term "chiral" refers to a compound or group which is not superimposable on its mirror image. A compound that is chiral is usually obtained as a mixture of two "enantiomers" as defined below. The term "atropisomer" refers to a specific kind of chiral compound that is chiral as the result of hindered internal bond rotation. Atropisomerism is reviewed in the following reference: Bringmann, G.; Price Mortimer, A. J.; Keller, P. A.; Gresser, M. J.; Garner, J.; Breuning, M. Angew. Chem., Int. Ed. 2005, 44, 5384. A compound that has a chiral center as the result of

atropisomerism will normally be obtained as a mixture of two enantiomers. These two enantiomers are denoted by the descriptors "M" and "P" according to rules described in the aforementioned reference by

Bringmann et al.

The term "deuterated" is intended to mean that at least one hydrogen has been replaced by deuterium, abbreviated herein as "D". The term "deuterated analog" refers to a structural analog of a compound or group in which one or more available hydrogens have been replaced with deuterium. In a deuterated compound or deuterated analog, the deuterium is present in at least 100 times the natural abundance level.

The term "diastereomers" and "diastereomeric" refers to

stereoisomers that are not enantiomers. Diastereomerism occurs when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the equivalent related stereocenters and are not mirror images of each other.

The term "diastereomeric pair of enantiomers" as it relates to a compound having at least four stereoisomers, refers to a set of two stereoisomers, where the stereoisomers in the set are mirror images and where the set is not a mirror image of any other sets of two stereoisomers.

The term "dopant" is intended to mean a material, within a layer including a host material, that changes the electronic characteristic(s) or the targeted wavelength(s) of radiation emission, reception, or filtering of the layer compared to the electronic characteristic(s) or the wavelength(s) of radiation emission, reception, or filtering of the layer in the absence of such material.

The term "enantiomers" is intended to mean stereoisomers that are mirror images of each other, where the mirror images cannot be

superimposed.

The prefix "hetero" indicates that one or more carbon atoms have been replaced with a different atom. In some embodiments, the different atom is N, O, or S.

The term "host material" is intended to mean a material, usually in the form of a layer, to which a dopant may be added. The host material may or may not have electronic characteristic(s) or the ability to emit, receive, or filter radiation.

The term "layer" is used interchangeably with the term "film" and refers to a coating covering a desired area. The term is not limited by size. The area can be as large as an entire device or as small as a specific functional area such as the actual visual display, or as small as a single sub-pixel. Layers and films can be formed by any conventional deposition technique, including vapor deposition, liquid deposition (continuous and discontinuous techniques), and thermal transfer. Continuous deposition techniques, include but are not limited to, spin coating, gravure coating, curtain coating, dip coating, slot-die coating, spray coating, and continuous nozzle coating or printing. Discontinuous deposition techniques include, but are not limited to, ink jet printing, gravure printing, and screen printing.

The terms "luminescent material" and "emitter" are intended to mean a material that emits light when activated by an applied voltage (such as in a light-emitting diode or light-emitting electrochemical cell).

The term "organic electronic device" or sometimes just "electronic device" is intended to mean a device including one or more organic semiconductor layers or materials.

The term "photoactive" refers to a material or layer that emits light when activated by an applied voltage (such as in a light emitting diode or chemical cell), that emits light after the absorption of photons (such as in down-converting phosphor devices), or that responds to radiant energy and generates a signal with or without an applied bias voltage (such as in a photodetector or a photovoltaic cell).

The term "silyl" refers to the group R₃Si-, where R is H, D, C1 -20 alkyl, fluoroalkyl, or aryl.

The term "stereoisomers" refers to isomeric molecules that have the same molecular formula and sequence of bonded atoms, but that differ only in the three-dimensional orientations of their atoms in space. One stereoisomer cannot be superimposed on another.

All groups may be unsubstituted or substituted. The substituent groups are discussed below.

In this specification, unless explicitly stated otherwise or indicated to the contrary by the context of usage, where an embodiment of the subject matter hereof is stated or described as comprising, including, containing, having, being composed of or being constituted by or of certain features or elements, one or more features or elements in addition to those explicitly stated or described may be present in the embodiment. An alternative embodiment of the disclosed subject matter hereof, is described as consisting essentially of certain features or elements, in which embodiment features or elements that would materially alter the principle of operation or the distinguishing characteristics of the

embodiment are not present therein. A further alternative embodiment of the described subject matter hereof is described as consisting of certain features or elements, in which embodiment, or in insubstantial variations thereof, only the features or elements specifically stated or described are present.

Also, use of "a" or "an" are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

Group numbers corresponding to columns within the Periodic Table of the elements use the "New Notation" convention as seen in the CRC Handbook of Chemistry and Physics, 81 ^st Edition (2000-2001 ).

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety, unless a particular passage is citedln case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

To the extent not described herein, many details regarding specific materials, processing acts, and circuits are conventional and may be found in textbooks and other sources within the organic light-emitting diode display, photodetector, photovoltaic cell, and semiconductive member arts. 2. Diastereomers of Formula I

The ligands in the composition of Formula I have the general structure shown below, where R³ is not shown:

These ligands are chiral because R¹ and R² are not the same. This can be easily understood by making reference to the diagram below. The Iigand and its mirror image are non-superimposable. Thus, two molecules in the diagram are enantiomers of one another. In principle, the two molecules in the diagram can interconvert if there is rotation about the bond connecting the phenyl group containing groups R¹ and R² and the nitrogen atom. However, this bond rotation in the ligands in the

complexes of Formula I is highly hindered. Thus, the enantiomers in the diagram below may be termed atropisomers. Depending on the identity of R1 , R2, and Ar'; one atropisomer will be denoted M and the other P.

It is well known that octahedral ML₃ complexes, wherein L is a bidentate ligand, are also chiral. This can be seen in the diagram below.

The two structures are non-superimposable mirror images. The two enantiomers can be described as defining left-handed ("Λ") or right- handed ("Δ") helices (see S. Herrero and M. A. Uson J. Chem. Ed. 1995, 72, 1065 for the naming convention).

When three chiral bidentate ligands are coordinated to a chiral metal center, stereoisomers result. There are eight possible

stereoisomers when three identical chiral bidentate ligands are complexed to an octahedral metal center. That is because the ligand is a racemate (a 50/50 mixture of enantiomers) and the Ir center is a racemate as well ("Λ" or "Δ" as shown above). These stereoisomers are actually four diastereomeric pairs of enantiomers. The lrl_₃ complex as formed, can be separated into four physically different diastereomeric pairs of

enantiomers. When the chiral bidentate ligands are atropisomers, they may be designated as "M" and "P". The four different diastereomeric pairs of lrl_3 enantiomers are thus designated as

(a) Λ-ΜΜΜ/Δ-ΡΡΡ,

(b) Δ-ΜΡΡ/Λ-ΡΜΜ.

(c) Λ-ΜΡΡ/Δ-ΡΜΜ, and

(d) Δ-ΜΜΜ/Λ-ΡΡΡ.

In the above designations, Δ and Λ refer to the stereochemistry of the iridium center, and M and P refer to stereochemistry of the ligands It is possible to distinguish between MMM/PPP and MPP/PMM

diastereomenc pairs of enantiomers by NMR. This determination is possible because in the MMM/PPP diastereomeric pairs of enantiomers all three ligands are equivalent, whereas in the MPP/PMM diastereomeric pairs of enantiomers they are all inequivalent. The relative configuration at Ir (i.e. Δ vs. Λ) can be determined by x-ray crystallography. In some cases it is only known whether the complex is an MMM/PPP or MPP/PMM diastereomeric pair of enantiomers. In those instances where x-ray quality crystals can be obtained, the relative configuration at Ir can be

determined.

In the description herein, the stereochemistry of the complexed ligand is characterized according to the rules described in Bringmann, et al. The assignment of the absolute configuration depends on the relative priority of the substituents that are attached to the two aromatic groups that are connected by the rotationally restricted bond. For example, in the two atropisomers below, Ph > iPr and Ar' > Phenyl. Application of the rules in Bringmann et al. leads to the atropisomers being designated as shown.

3. Compositions having Formula I

There is provided herein a composition capable of being separated into diastereomeric pairs of enantiomers, the composition having Formula I. By this it is meant that distinct compositions can be isolated where the compositions consist essentially of n diastereomeric pairs of enantiomers, where n is 1 , 2, or 3. While many iridium complexes have eight stereoisomeric forms, as discussed above, not all are capable of being separated into the

diastereomenc pairs of enantiomers. It has been found, that the

complexes of Formula I can be separated into diastereomeric pairs of enantiomers. In some embodiments, a mixture of n diastereomeric pairs of enantiomers can be isolated, where n is 1 , 2, or 3. In some

embodiments, a mixture of two diastereomeric pairs of enantiomers can be isolated. In some embodiments, a single diastereomeric pair of enantiomers can be isolated.

There is also provided herein a composition consisting essentially of n diastereomeric pairs of enantiomers having Formula I, where n is 1 or 2. By this it is meant that there are one or two diastereomeric pairs of enantiomers and no other stereoisomers of the composition are present.

Formula I has the structure

Formula I

wherein:

Ar' is selected from the group consisting of aryl and deuterated aryl;

R¹ is selected from the group consisting of H, D, alkyl, silyl, aryl, and deuterated analogs thereof;

R² is different from R¹ and is selected from the group consisting of H, D, alkyl, silyl, aryl, and deuterated analogs thereof, with the proviso that no more than one of R¹ and R² is H or D;

R³ is the same or different at each occurrence and is selected from the group consisting of D, alkyl, silyl, aryl, and deuterated analogs thereof; a is an integer from 0-3; and

b is an integer from 0-4.

In some embodiments, the composition consists essentially of one diastereomeric pair of enantiomers.

In some embodiments, the composition consists essentially of two diastereomeric pairs of enantiomers. The two pairs have the same molecular formula and sequence of atoms and differ only in the three- dimensional orientation of their atoms. The two pairs are not mirror images of each other.

In some embodiments, the composition consists essentially of three diastereomeric pairs of enantiomers. The three pairs have the same molecular formula and sequence of atoms and differ only in the three- dimensional orientation of their atoms. None of the three pairs is a mirror image of another of the three pairs.

In some embodiments, the composition of Formula I is deuterated.

In some embodiments, the composition of Formula I is at least 10% deuterated. By "% deuterated" or "% deuteration" is meant the ratio of deuterons to the total of hydrogens plus deuterons, expressed as a percentage. The deuteriums may be on the same or different groups. In some embodiments, the diastereomeric pair of enantiomers of Formula I is at least 25% deuterated; in some embodiments, at least 50% deuterated; in some embodiments, at least 75% deuterated; in some embodiments, at least 90% deuterated.

In some embodiments, Ar' is selected from the group consisting of phenyl, biphenyl, naphthyl, substituted derivatives thereof, and deuterated analogs thereof. In some embodiments, substituents are selected from the group consisting of phenyl, 1 -napthyl, 1 -naphthyl, C1 -10 alkyl, C3-12 silyl, and deuterated analogs thereof.

In some embodiments, Ar' has Formula II

Formula II

wherein:

R⁴ is selected from the group consisting of alkyl, silyl, aryl, and

deuterated analogs thereof, and

^* indicates the point of attachment to the triazine ring of the ligand.

In some embodiments, R⁴ is selected from the group consisting of phenyl, C1 -10 alkyl, C3-12 silyl, and deuterated analogs thereof.

In some embodiments, R¹ is selected from H and D.

In some embodiments, R¹ is an unsubstituted alkyl or unsubstituted deuterated alkyl having 1 -6 carbons.

In some embodiments, R¹ is an unsubstituted alkyl or unsubstituted deuterated alkyl having 1 -3 carbons.

In some embodiments, R¹ is a silyl or deuterated silyl having 3-6 carbons.

In some embodiments, R¹ is a C6-12 aryl or C6-12 deuterated aryl.

In some embodiments, R¹ is phenyl or deuterated phenyl.

In some embodiments, R² is selected from H and D.

In some embodiments, R² is an unsubstituted alkyl or unsubstituted deuterated alkyl having 1 -6 carbons.

In some embodiments, R² is an unsubstituted alkyl or unsubstituted deuterated alkyl having 1 -3 carbons.

In some embodiments, R² is a silyl or deuterated silyl having 3-6 carbons.

In some embodiments, R² is a C6-12 aryl or C6-12 deuterated aryl. In some embodiments, R² is phenyl or deuterated phenyl.

In some embodiments, a = 0.

In some embodiments, a = 1 .

In some embodiments, a = 1 and R³ is para to the triazine nitrogen. In some embodiments, a = 2.

In some embodiments, a > 0 and R³ is an alkyl or deuterated alkyl having 1 -6 carbons.

In some embodiments, a > 0 and R³ is a silyl or deuterated silyl having 3-6 carbons. In some embodiments, a > 0 and R³ is a hydrocarbon aryl or deuterated hydrocarbon aryl having 6-12 ring carbons.

In some embodiments, a > 0 and R³ is an alkylaryl or deuterated alkylaryl having 6-20 carbons.

In some embodiments, b = 0.

In some embodiments, b = 1 .

In some embodiments, b = 2.

In some embodiments, b > 0 and R³ is an alkyl or deuterated alkyl having 1 -6 carbons.

In some embodiments, b > 0 and R³ is a silyl or deuterated silyl having 3-6 carbons.

In some embodiments, b > 0 and R³ is a hydrocarbon aryl or deuterated hydrocarbon aryl having 6-12 ring carbons.

In some embodiments, b > 0 and R³ is an alkylaryl or deuterated alkylaryl having 6-20 carbons.

Any of the above embodiments can be combined with one or more of the other embodiments, so long as they are not mutually exclusive and with the proviso that no more than one of R¹ and R² is H or D, and R¹≠ R². For example, the embodiment in which R¹ is an alkyl or deuterated alkyl having 3-20 carbons can be combined with the embodiment in which R² is phenyl or deuterated phenyl and the embodiment where the composition consists essentially of one diastereomeric pair of enantiomers. The same is true for the other non-mutually-exclusive embodiments discussed above. The skilled person would understand which embodiments were mutually exclusive and would thus readily be able to determine the combinations of embodiments that are contemplated by the present application.

In the discussion herein, reference to "the diastereomeric pair of enantiomers" is intended to refer to n diastereomeric pairs of enantiomers, where n is 1 , 2, or 3.

In some embodiments, the composition having Formula I is useful as an emissive material in electroluminescent or photoluminescent applications. In some embodiments, the composition having Formula I is capable of blue electroluminescence. The composition can be used alone or as a dopant in a host material.

The compositions having Formula I are soluble in many commonly used organic solvents. Solutions of these compounds can be used for liquid deposition using techniques such as discussed above. In some embodiments, the compositions have an EL peak in the range of 445-490 nm. In some embodiments, the compounds used in devices result in color coordinates of x < 0.25 and y < 0.5, according to the 1931 CLE.

convention (Commission Internationale de L'Eclairage, 1931 ).

In some embodiments, the compositions having Formula I can provide advantages in electronic devices.

In some embodiments, the compositions having Formula I is used in light-emitting devices. In some embodiments, devices made with n diastereomeric pairs of enantiomers having Formula I have improved efficiencies and lifetimes. This is advantageous for reducing energy consumption in all types of devices, and particularly for lighting

applications. Higher efficiency also improves device lifetime at constant luminance. In some embodiments, devices made with n diastereomeric pairs of enantiomers have improved color.

In some embodiments, the composition having Formula I is used as a down-converting phosphor in devices. In some embodiments, n diastereomeric pairs of enantiomers have improved efficiency and/or color.

In some embodiments, the compositions having Formula I exhibits biological activity. In some embodiments, one or more diastereomeric pairs of enantiomers can be more active than others.

In some embodiments, the compositions having Formula I exhibits antiangiogenic properties. In some embodiments, one or more

diastereomeric pair of enantiomers can be more effective than others.

In some embodiments, the compositions having Formula I provides utility as a singlet oxygen photosensitizer or scavenger. In some embodiments, one or more diastereomeric pair of enantiomers can be more effective than others. Examples of compositions having Formula I from which the diastereomenc pairs of enantiomers can be separated include, but are not limited to, those shown below. As discussed above, the diastereomeric pairs of enantiomers are classified as follows:

(a) Λ-ΜΜΜ/Δ-ΡΡΡ,

(b) Δ-ΜΡΡ/Λ-ΡΜΜ.

(c) Λ-ΜΡΡ/Δ-ΡΜΜ, and

(d) Δ-ΜΜΜ/Λ-ΡΡΡ.

Compositions B1 -B9 are understood to contain all of these possible diastereomers, which may or may not be separated prior to their incorporation into a luminescent device.

Composition B1

Composition B2

Com osition B3

nnposition B4

Composition B5

Composition B6

Composition B7

Composition B8

Composition B9

4. Synthesis

The ligands for the compositions having Formula I described herein can be synthesized by a variety of procedures that have precedent in the literature. The exact procedure chosen will depend on a variety of factors, including availability of starting materials and reaction yield.

In one method a diaryl 1 ,3,4-oxadiazole is prepared from a carboxylic acid and an acyl hydrazide (Dickson, H. D.; Li, C. Tet. Lett. 2009, 50, 6435). The 1 ,3,4-oxadiazole is then allowed to react with an aniline in the presence of aluminum chloride to afford the desired 4H- 1 ,2,4-triazole (Chiriac, C. I. et al., Rev. Roum. Chim. 2010, 55, 175). An example of this method is shown below, where HATU = 2~(7~Aza-1 H- Benzo riazole -1 -yi)-1 ,1 ,3,3- tetramethyluronium hexafluorophosphate, DIEA = diisopropy!ethy!amine, Burgess Reagent = methyl N- (triethylammoniumsulfonyl)carbamate, THF = tetrahydrofuran, and NMP = 1 -methyl-2-pyrollidinone).

In another method, 2-phenyl-1 ,3,4-oxadiazole is allowed to react with an aniline, affording a diaryl-substituted triazole (Korotikh, N.I. et al. Chemistry of Heterocyclic Compounds 2005, 41, 866). The triazole is then allowed to react with N-bromosuccinimide affording a brominated 1 ,2,4- triazole, which then undergoes Suzuki coupling to afford a triaryl- substituted 4H-1 ,2,4-triazole. An example of this method is shown below:

Reflux

The Huisgen rearrangement reaction is yet another method that was used to prepare sterically hindered 4H-1 ,2,4-triazoles (Kaim, L. E.; Grimaud, L; Patil, P. Org. Lett. 2011 , 13, 1261 .). The rearrangement takes advantage of the fast kinetics of an intramolecular cyclization driven by generation of N₂ to form bonds between bulky groups. The synthetic sequence is summarized below. It is modular and convergent, allowing for flexibility in tuning the substituents on the triazole core. The starting materials for the Huisgen rearrangement can be prepared from the readily available isonitrile and 5-phenyl-1 H-tetrazole. In the same pot, the tetrazolyl imidoyl bromide undergoes rearrangement to from 3-bromo- 1 ,2,4-triazole. The last step of the ligand synthesis is the Suzuki-Miyaura cross-coupling reaction.

The compositions having Formula I were prepared by the reaction of commercially available lr(acetylacetonate)3 with excess ligand at elevated temperatures. This reaction typically results in cyclometallation of three equivalents of ligand onto iridium and formation of three equivalents of acetylacetone. The lrl_₃ product, wherein L is the

cyclometallated ligand, can be isolated and purified by chromatography and/or recrystallization.

The diastereomeric pairs of enantiomers can be separated by chromatographic methods, such as flash chromatography or high performance liquid chromatography. The structure of the diastereomeric pair of enantiomers can be determined by NMR and x-ray crystallography, as discussed above.

5. Devices

Organic electronic devices that may benefit from having one or more layers comprising the diastereomeric pairs of enantiomers having Formula I described herein include, but are not limited to, (1 ) devices that convert electrical energy into radiation (e.g., a light-emitting diode, light emitting diode display, lighting device, luminaire, or diode laser); (2) devices that detect signals through electronics processes (e.g.,

photodetectors, photoconductive cells, photoresistors, photoswitches, phototransistors, phototubes, IR detectors, biosensors); (3) devices that convert radiation into electrical energy, (e.g., a photovoltaic device or solar cell); (4) devices that convert light of one wavelength to light of a longer wavelength, (e.g., a down-converting phosphor device); and (5) devices that include one or more electronic components that include one or more organic semi-conductor layers (e.g., a transistor or diode).

One illustration of an organic electronic device structure is shown in FIG. 1 . The device 100 has a first electrical contact layer, an anode layer 1 10 and a second electrical contact layer, a cathode layer 160, and a photoactive layer 140 between them. Adjacent to the anode is a hole injection layer 120. Adjacent to the hole injection layer is a hole transport layer 130, comprising hole transport material. Adjacent to the cathode may be an electron transport layer 150, comprising an electron transport material. As an option, devices may use one or more additional hole injection or hole transport layers (not shown) next to the anode 1 10 and/or one or more additional electron injection or electron transport layers (not shown) next to the cathode 160. As a further option, devices may have an anti-quenching layer (not shown) between the photoactive layer 140 and the electron transport layer 150.

Layers 120 through 150, and any additional layers between them, are individually and collectively referred to as the active layers.

In some embodiments, the photoactive layer is pixellated, as shown in FIG. 2. In device 200, layer 140 is divided into pixel or subpixel units 141 , 142, and 143 which are repeated over the layer. Each of the pixel or subpixel units represents a different color. In some embodiments, the subpixel units are for red, green, and blue. Although three subpixel units are shown in the figure, two or more than three may be used.

In some embodiments, the different layers have the following range of thicknesses: anode 1 10, 500-5000 A, in some embodiments, 1000- 2000 A; hole injection layer 120, 50-2000 A, in some embodiments, 200- 1000 A; hole transport layer 130, 50-2000 A, in some embodiments, 200- 1000 A; photoactive layer 140, 10-2000 A, in some embodiments, 100- 1000 A; electron transport layer 150, 50-2000 A, in some embodiments, 100-1000 A; cathode 160, 200-10000 A, in some embodiments, 300-5000 A. The desired ratio of layer thicknesses will depend on the exact nature of the materials used.

In some embodiments, the diastereomeric pair of enantiomers having Formula I is useful as the emissive material in photoactive layer 140, having blue emission color. The diastereomeric pair of enantiomers can be used alone or as a dopant in a host material.

a. Photoactive Layer

In some embodiments, the photoactive layer includes a host material and a composition having Formula I as a dopant. In some embodiments a second host material may be present. In some

embodiments, the photoactive layer consists essentially of a host material and a composition having Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present. In some embodiments, the photoactive layer consists essentially of a first host material, a second host material, and a composition having Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present.

In some embodiments, the photoactive layer includes a host material and n diastereomeric pairs of enantiomers having Formula I as a dopant, where n = 1 , 2, or 3, and no other diastereomeric pairs of enantiomers having the same chemical formula are present. In some embodiments, a second host material may be present. In some

embodiments, the photoactive layer consists essentially of a host material and n diastereomeric pairs of enantiomers having Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present. In some embodiments, the photoactive layer consists essentially of a first host material, a second host material, and n diastereomeric pairs of enantiomers having Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present.

In some embodiments, the photoactive layer consists essentially of a host material and three diastereomeric pairs of enantiomers having Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present. In some embodiments, the photoactive layer consists essentially of a first host material, a second host material, and three diastereomeric pairs of enantiomers having Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present.

In some embodiments, the photoactive layer consists essentially of a host material and two diastereomeric pairs of enantiomers having

Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present. In some embodiments, the photoactive layer consists essentially of a first host material, a second host material, and two diastereomeric pairs of enantiomers having Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present.

In some embodiments, the photoactive layer consists essentially of a host material and one diastereomeric pairs of enantiomers having

Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present. In some embodiments, the photoactive layer consists essentially of a first host material, a second host material, and one diastereomeric pairs of enantiomers having Formula I as a dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present. In some embodiments, the weight ratio of dopant to total host material is in the range of 5:95 to 70:30; in some embodiments, 10:90 to 20:80.

In some embodiments, the host has a triplet energy level higher than that of the dopant, so that it does not quench the emission. In some embodiments, the host is selected from the group consisting of

carbazoles, indolocarbazoles, triazines, aryl ketones, phenylpyridines, pyrimidines, phenanthrolines, triarylamines, deuterated analogs thereof, combinations thereof, and mixtures thereof.

In some embodiments, the photoactive layer is intended to emit white light. In some embodiments, the photoactive layer comprises a host, a composition having Formula I, and one or more additional dopants emitting different colors, so that the overall emission is white. In some embodiments, the photoactive layer consists essentially of a host, a first dopant which is a composition having Formula I, and a second dopant, where the second dopant emits a different color than the first dopant, and where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present. In some embodiments, the emission color of the second dopant is yellow. In some embodiments, the photoactive layer consists

essentially of a host, a first dopant which is a composition having Formula I, a second dopant, and a third dopant, where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present. In some embodiments, the emission color of the second dopant is red and the emission color of the third dopant is green.

In some embodiments, the photoactive layer is intended to emit white light. In some embodiments, the photoactive layer comprises a host, n diastereomeric pair of enantiomers of Formula I, and one or more additional dopants emitting different colors, so that the overall emission is white. In some embodiments, the photoactive layer consists essentially of a host, a first dopant which is n diastereomeric pairs of enantiomers having Formula I, and a second dopant, where the second dopant emits a different color than the first dopant, and where features or elements that would materially alter the principle of operation or the distinguishing characteristics of the embodiment are not present. In some

embodiments, the emission color of the second dopant is yellow. In some embodiments, the photoactive layer consists essentially of a host, a first dopant which is n diastereomeric pair of enantiomers having Formula I, a second dopant, and a third dopant, where features or elements that would materially alter the principle of operation or the distinguishing

characteristics of the embodiment are not present. In some embodiments, the emission color of the second dopant is red and the emission color of the third dopant is green.

Any kind of electroluminescent ("EL") material can be used as second and third dopants. EL materials include, but are not limited to, small molecule organic fluorescent compounds, luminescent metal complexes, conjugated polymers, and mixtures thereof. Examples of fluorescent compounds include, but are not limited to, chrysenes, pyrenes, perylenes, rubrenes, coumarins, anthracenes, thiadiazoles, derivatives thereof, arylamino derivatives thereof, and mixtures thereof. Examples of metal complexes include, but are not limited to, metal chelated oxinoid compounds, such as tris(8-hydroxyquinolato)aluminum (Alq3);

cyclometalated iridium and platinum electroluminescent compounds, such as complexes of iridium with phenylpyridine, phenylquinoline, or

phenylpyrimidine ligands as disclosed in Petrov et al., U.S. Patent

6,670,645 and Published PCT Applications WO 03/063555 and WO 2004/016710, and organometallic complexes described in, for example, Published PCT Applications WO 03/008424, WO 03/091688, and WO 03/040257, and mixtures thereof. Examples of conjugated polymers include, but are not limited to poly(phenylenevinylenes), polyfluorenes, poly(spirobifluorenes), polythiophenes, poly(p-phenylenes), copolymers thereof, and mixtures thereof.

Examples of red, orange and yellow light-emitting materials include, but are not limited to, complexes of Ir having phenylquinoline or

phenylisoquinoline ligands, periflanthenes, fluoranthenes, and perylenes. Red light-emitting materials have been disclosed in, for example, US patent 6,875,524, and published US application 2005-0158577.

In some embodiments, the second and third dopants are

cyclometallated complexes of Ir or Pt. b. Other Device Layers

The other layers in the device can be made of any materials which are known to be useful in such layers.

The anode 1 10 is an electrode that is particularly efficient for injecting positive charge carriers. It can be made of, for example materials containing a metal, mixed metal, alloy, metal oxide or mixed-metal oxide, or it can be a conducting polymer, and mixtures thereof. Suitable metals include the Group 1 1 metals, the metals in Groups 4, 5, and 6, and the Group 8-10 transition metals. If the anode is to be light-transmitting, mixed-metal oxides of Groups 12, 13 and 14 metals, such as indium-tin- oxide, are generally used. The anode may also comprise an organic material such as polyaniline as described in "Flexible light-emitting diodes made from soluble conducting polymer," Nature vol. 357, pp 477 479 (1 1 June 1992). At least one of the anode and cathode should be at least partially transparent to allow the generated light to be observed.

The hole injection layer 120 comprises hole injection material and may have one or more functions in an organic electronic device, including but not limited to, planarization of the underlying layer, charge transport and/or charge injection properties, scavenging of impurities such as oxygen or metal ions, and other aspects to facilitate or to improve the performance of the organic electronic device. The hole injection layer can be formed with polymeric materials, such as polyaniline (PANI) or polyethylenedioxythiophene (PEDOT), which are often doped with protonic acids. The protonic acids can be, for example, poly(styrenesulfonic acid), poly(2-acrylamido-2-methyl-1 -propanesulfonic acid), and the like.

The hole injection layer can comprise charge transfer compounds, and the like, such as copper phthalocyanine and the tetrathiafulvalene- tetracyanoquinodimethane system (TTF-TCNQ). In some embodiments, the hole injection layer comprises at least one electrically conductive polymer and at least one fluorinated acid polymer.

In some embodiments, the hole injection layer is made from an aqueous dispersion of an electrically conducting polymer doped with a colloid-forming polymeric acid. Such materials have been described in, for example, published U.S. patent applications US 2004/0102577, US

2004/0127637, US 2005/0205860, and published PCT application WO 2009/018009.

Examples of hole transport materials for layer 130 have been summarized for example, in Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Vol. 18, p. 837-860, 1996, by Y. Wang. Both hole transporting molecules and polymers can be used. Commonly used hole transporting molecules are: N,N'-diphenyl-N,N'-bis(3-methylphenyl)- [1 ,1 '-biphenyl]-4,4'-diamine (TPD), 1 ,1 -bis[(di-4-tolylamino)

phenyljcyclohexane (TAPC), N,N'-bis(4-methylphenyl)-N,N'-bis(4- ethylphenyl)-[1 ,1 '-(3,3'-dimethyl)biphenyl]-4,4'-diamine (ETPD), tetrakis-(3- methylphenyl)-N,N,N',N'-2,5-phenylenediamine (PDA), a-phenyl-4-Ν,Ν- diphenylaminostyrene (TPS), p-(diethylamino)benzaldehyde

diphenylhydrazone (DEH), triphenylamine (TPA), bis[4-(N,N- diethylamino)-2-methylphenyl](4-methylphenyl)methane (MPMP),

1 -phenyl-3-[p-(diethylamino)styryl]-5-[p-(diethylamino)phenyl] pyrazoline (PPR or DEASP), 1 ,2-trans-bis(9H-carbazol-9-yl)cyclobutane (DCZB), N,N,N',N'-tetrakis(4-methylphenyl)-(1 ,1 '-biphenyl)-4,4'-diamine (TTB), N,N'-bis(naphthalen-1 -yl)-N,N'-bis-(phenyl)benzidine ( -NPB), and porphyrinic compounds, such as copper phthalocyanine. In some embodiments, the hole transport layer comprises a hole transport polymer. In some embodiments, the hole transport polymer is a distyrylaryl compound. In some embodiments, the aryl group has two or more fused aromatic rings. In some embodiments, the aryl group is an acene. The term "acene" as used herein refers to a hydrocarbon parent component that contains two or more ortho-lused benzene rings in a straight linear arrangement. Other commonly used hole transporting polymers are polyvinylcarbazole, (phenylmethyl)-polysilane, and polyaniline. It is also possible to obtain hole transporting polymers by doping hole transporting molecules such as those mentioned above into polymers such as polystyrene and polycarbonate. In some cases, triarylamine polymers are used, especially triarylamine-fluorene copolymers. In some cases, the polymers and copolymers are crosslinkable. .

In some embodiments, the hole transport layer further comprises a p-dopant. In some embodiments, the hole transport layer is doped with a p-dopant. Examples of p-dopants include, but are not limited to, tetrafluorotetracyanoquinodimethane (F4-TCNQ) and perylene-3,4,9,10- tetracarboxylic-3,4,9,10-dianhydride (PTC DA).

Examples of electron transport materials which can be used for layer 150 include, but are not limited to, metal chelated oxinoid

compounds, including metal quinolate derivatives such as tris(8- hydroxyquinolato)aluminum (AIQ), bis(2-methyl-8-quinolinolato)(p- phenylphenolato) aluminum (BAIq), tetrakis-(8-hydroxyquinolato)hafnium (HfQ) and tetrakis-(8-hydroxyquinolato)zirconium (ZrQ); and azole compounds such as 2- (4-biphenylyl)-5-(4-t-butylphenyl)-1 ,3,4-oxadiazole (PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1 ,2,4-triazole (TAZ), and 1 ,3,5-tri(phenyl-2-benzimidazole)benzene (TPBI); quinoxaline derivatives such as 2,3-bis(4-fluorophenyl)quinoxaline; phenanthrolines such as 4,7-diphenyl-1 ,10-phenanthroline (DPA) and 2, 9-di methyl -4,7- diphenyl-1 ,10-phenanthroline (DDPA); and mixtures thereof. In some embodiments, the electron transport layer further comprises an n-dopant. N-dopant materials are well known. The n-dopants include, but are not limited to, Group 1 and 2 metals; Group 1 and 2 metal salts, such as LiF, CsF, and CS2CO3; Group 1 and 2 metal organic compounds, such as Li quinolate; and molecular n-dopants, such as leuco dyes, metal complexes, such as W₂(hpp)₄ where hpp=1 ,3,4,6,7,8-hexahydro-2H-pyrimido-[1 ,2-a]- pyrimidine and cobaltocene, tetrathianaphthacene,

bis(ethylenedithio)tetrathiafulvalene, heterocyclic radicals or diradicals, and the dimers, oligomers, polymers, dispiro compounds and polycydes of heterocyclic radical or diradicals. An anti-quenching layer may be present between the photoactive layer and the electron transport layer to prevent quenching of blue luminance by the electron transport layer. To prevent energy transfer quenching, the triplet energy of the anti-quenching material has to be higher than the triplet energy of the blue emitter. To prevent electron transfer quenching, the LUMO level of the anti-quenching material has to be shallow enough (with respect to the vacuum level) such that electron transfer between the emitter exciton and the anti-quenching material is endothermic. Furthermore, the HOMO level of the anti-quenching material has to be deep enough (with respect to the vacuum level) such that electron transfer between the emitter exciton and the anti-quenching material is endothermic. In general, anti-quenching material is a large band-gap material with high triplet energy.

Examples of materials for the anti-quenching layer include, but are not limited to, tnphenylene, tnphenylene derivatives, carbazole, carbazole derivatives, and deuterated analogs thereof. Some specific materials include those shown below.

An optional electron injection layer may be deposited over the electron transport layer. Examples of electron injection materials include, but are not limited to, Li-containing organometallic compounds, LiF, Li₂O, Li quinolate, Cs-containing organometallic compounds, CsF, Cs₂O, and CS2CO3. This layer may react with the underlying electron transport layer, the overlying cathode, or both. When an electron injection layer is present, the amount of material deposited is generally in the range of 1 - 100 A, in some embodiments 1 -10 A.

The cathode 160, is an electrode that is particularly efficient for injecting electrons or negative charge carriers. The cathode can be any metal or nonmetal having a lower work function than the anode. Materials for the cathode can be selected from alkali metals of Group 1 (e.g., Li, Cs), the Group 2 (alkaline earth) metals, the Group 12 metals, including the rare earth elements and lanthanides, and the actinides. Materials such as aluminum, indium, calcium, barium, samarium and magnesium, as well as combinations, can be used. It is known to have other layers in organic electronic devices. For example, there can be a layer (not shown) between the anode 1 10 and hole injection layer 120 to control the amount of positive charge injected and/or to provide band-gap matching of the layers, or to function as a protective layer. Layers that are known in the art can be used, such as copper phthalocyanine, silicon oxy-nitride, fluorocarbons, silanes, or an ultra-thin layer of a metal, such as Pt. Alternatively, some or all of anode layer 1 10, active layers 120, 130, 140, and 150, or cathode layer 160, can be surface-treated to increase charge carrier transport efficiency. The choice of materials for each of the component layers is preferably determined by balancing the positive and negative charges in the emitter layer to provide a device with high electroluminescence efficiency.

It is understood that each functional layer can be made up of more than one layer. c. Device Fabrication

The device layers can be formed by any deposition technique, or combinations of techniques, including vapor deposition, liquid deposition, and thermal transfer.

In some embodiments, the device is fabricated by liquid deposition of the hole injection layer, the hole transport layer, and the photoactive layer, and by vapor deposition of the anode, the electron transport layer, an electron injection layer and the cathode.

The hole injection layer can be deposited from any liquid medium in which it is dissolved or dispersed and from which it will form a film. In one embodiment, the liquid medium consists essentially of one or more organic solvents. In one embodiment, the liquid medium consists essentially of water or water and an organic solvent. The hole injection material can be present in the liquid medium in an amount from 0.5 to 10 percent by weight. The hole injection layer can be applied by any continuous or discontinuous liquid deposition technique. In one

embodiment, the hole injection layer is applied by spin coating. In one embodiment, the hole injection layer is applied by ink jet printing. In one embodiment, the hole injection layer is applied by continuous nozzle printing. In one embodiment, the hole injection layer is applied by slot-die coating. After liquid deposition, the liquid medium can be removed in air, in an inert atmosphere, or by vacuum, at room temperature or with heating.

The hole transport layer can be deposited from any liquid medium in which it is dissolved or dispersed and from which it will form a film. In one embodiment, the liquid medium consists essentially of one or more organic solvents. In one embodiment, the liquid medium consists essentially of water or water and an organic solvent. In one embodiment the organic solvent is an aromatic solvent. In one embodiment, the organic liquid is selected from chloroform, dichloromethane,

chlorobenzene, dichlorobenzene, toluene, xylene, mesitylene, anisole, and mixtures thereof. The hole transport material can be present in the liquid medium in a concentration of 0.2 to 2 percent by weight. The hole transport layer can be applied by any continuous or discontinuous liquid deposition technique. In one embodiment, the hole transport layer is applied by spin coating. In one embodiment, the hole transport layer is applied by ink jet printing. In one embodiment, the hole transport layer is applied by continuous nozzle printing. In one embodiment, the hole transport layer is applied by slot-die coating. After liquid deposition, the liquid medium can be removed in air, in an inert atmosphere, or by vacuum, at room temperature or with heating.

The photoactive layer can be deposited from any liquid medium in which it is dissolved or dispersed and from which it will form a film. In one embodiment, the liquid medium consists essentially of one or more organic solvents. In one embodiment, the liquid medium consists essentially of water or water and an organic solvent. In one embodiment the organic solvent is an aromatic solvent. In one embodiment, the organic solvent is selected from chloroform, dichloromethane, toluene, anisole, 2-butanone, 3-pentanone, butyl acetate, acetone, xylene, mesitylene, chlorobenzene, tetrahydrofuran, diethyl ether, trifluorotoluene, and mixtures thereof. The photoactive material can be present in the liquid medium in a concentration of 0.2 to 2 percent by weight. Other weight percentages of photoactive material may be used depending upon the liquid medium. The photoactive layer can be applied by any continuous or discontinuous liquid deposition technique. In one embodiment, the photoactive layer is applied by spin coating. In one embodiment, the photoactive layer is applied by ink jet printing. In one embodiment, the photoactive layer is applied by continuous nozzle printing. In one embodiment, the photoactive layer is applied by slot-die coating. After liquid deposition, the liquid medium can be removed in air, in an inert atmosphere, or by vacuum, at room temperature or with heating.

The electron transport layer can be deposited by any vapor deposition method. In one embodiment, it is deposited by thermal evaporation under vacuum.

The electron injection layer can be deposited by any vapor deposition method. In one embodiment, it is deposited by thermal evaporation under vacuum.

The cathode can be deposited by any vapor deposition method. In one embodiment, it is deposited by thermal evaporation under vacuum.

EXAMPLES

The concepts described herein will be further described in the following examples, which do not limit the scope of the invention described in the claims.

Synthesis Example 1

This example illustrates the preparation of Composition B1 .

Step 1 : 2,4-diphenyl-6-isopropylaniline

A catalyst solution was prepared by combining Pd2(dba)3 (0.92 g, 0.90 mmol) and S-Phos (1 .6 g, 3.9 mmol) in toluene (30 ml_) and stirring the mixture at room temperature for 30 min. 2,4-Dibromo-6-isopropylaniline (15.0 g, 51 .2 mmol), phenylboronic acid (19.4 g, 143 mmol) and potassium phosphate monohydrate (70.7 g, 307 mmol) were combined in toluene (300 ml_) and stirred for 40 min. The pre-prepared catalyst mixture was added and the resulting reaction mixture heated to reflux. After 2.2 h at reflux, the reaction mixture was cooled to room temperature, diluted with 600 mL of ethyl acetate, filtered through a pad of Celite,^® washed several times with ethyl acetate, and concentrated under vacuum to afford an oil. Due to the large amount of material, the crude product was divided in half and chromatographed in two batches on pre-packed 340 g Biotage^® silica gel columns with ethyl acetate/hexane as the eluent.

The product containing fractions were concentrated to dryness to afford 2,4-diphenyl-6-isopropylaniline as a red oil. The second batch contained a small amount of an impurity not observed in the first batch (5.4 g); it was further purified by redissolving in ethyl acetate and adding aqueous HCI dropwise to precipitate an off-white solid. The solid was filtered off and dissolved in a mixture of ethyl aceate and saturated

NaHCO3. The resulting mixture was washed with saturated NaHCO3 and brine, the ethyl acetate layer dried over NaSO₄, and concentrated to afford 5.1 g of product. Total yield = 10. 5 g (71 %). ¹ H NMR (CD₂CI₂) δ 7.68 (mult, 2H, ArH), 7.56 (mult, 5H, ArH), 7.47 (mult, 3H, ArH), 7.35 (mult, 2H, ArH), 3.93 (br, 2H, NH₂), 3.06 (sept, J = 7 Hz, 1 H, CH(CH₃)₂), 1 .44 (d, J = 7 Hz, 6H, CH(CH₃)₂). ¹³C NMR (CD₂CI₂) 5141 .6, 140.4, 140.2, 133.1 , 130.9, 129.4, 128.9, 128.7, 128.4, 127.3, 126.5, 126.4, 126.2, 123.4, 28.2, 22.3. Exact mass for C₂i H₂₂N calc'd: 288.175; Found: 288.175. Step 2: 4-(5'-isopropyl-[1 ,1 ':3',1 "-terphenyl]-4'-yl)-3-phenyl-4H-1 ,2,4- triazole

A solution of 2-phenyl-1 ,3,4-oxadiazole (2.24 g, 15.3 mmol), 2,4-diphenyl- 6-isopropylaniline, (4.40 g, 15.3 mmol) and trifluoroacetic acid (1 .75 g, 15.3 mmol) in ortho-dichlorobenzene (20 mL) was heated at reflux for 15 h. The mixture was cooled to room temperature and concentrated to dryness. The crude product was redissolved in ethyl acetate and extracted with aqueous K2CO3 and with brine. The aqueous layers were combined and extracted with ethyl acetate until the extracts no longer contained product by TLC. The combined organic layers were dried over MgSO₄ and concentrated to dryness. The crude product was chromatographed on a pre-packed 340 g Biotage® silica gel column with ethyl acetate/hexane as the eluent. The product containing fractions were combined and concentrated to dryness affording 4.70 g of a white solid (74%). ¹ H NMR (CD2CI2) 58.1 1 (s, 1 H, triazoleC5-H), 7.73 (s, 1 H, ArH), 7.70 (d, J = 8 Hz, 2H, ArH), 7.52 (mult, 3H, ArH), 7.42 (t, J = 8 Hz, 1 H, ArH), 7.32 (mult, 3H, ArH), 7.23 (mult, 3H, ArH), 7.16 (t, J = 8 Hz, 2H, ArH), 6.84 (d, J = 8 Hz, 2H, ArH), 2.72 (sept, 1 H, CH(CH₃)₂), 1 .26 (d, J = 7 Hz, 3H, CH(CH₃)₂), 1 .07 (d, J = 7 Hz, 3H, CH(CH₃)₂). ¹³C NMR (CD₂CI₂) 5153.5, 146.4, 145.6, 143.1 , 140.4, 139.8, 137.8, 129.7, 129.4, 129.0, 128.5, 128.33, 128.29, 128.2, 127.69, 127.66, 127.4, 127.2, 126.9, 125.1 , 28.4, 24.8, 22.6. Exact mass for C₂₉H₂₆N₃ calc'd: 416.213; Found: 416.213. Step 3: 3-bromo-4-(5'-isopropyl-[1 ,1 ':3',1 "-terphenyl]-4'-yl)-5-phenyl-4H- 1 ,2,4-triazole

4-(5'-isopropyl-[1 ,1 ':3',1 "-terphenyl]-4'-yl)-3-phenyl-4H-1 ,2,4-triazole (4.0 g, 9.7 mmol) and N-bromosuccinimide (2.60 g, 1 1 .7 mmol) were dissolved in a 50/50 carbon tetrachloride/acetic acid solution (50ml_). The reaction mixture was heated at reflux for 16 h and then cooled to room temperature. Water (50 ml_) and methylene chloride (25 ml_) were added to the reaction mixture, followed by sufficient saturated aqueous NaHCO3 to neutralize the acetic acid. The mixture was washed with saturated aqueous NaHCO3, and the combined aqueous washes extracted with methylene chloride. The organic extracts were combined, dried (MgSO ), and concentrated to dryness. The crude product was chromatographed on a pre-packed 340 g Biotage® silica gel column with ethyl acetate/hexane as the eluent. The product containing fractions were combined and concentrated to dryness affording 3.85 g of a white solid. This was redissolved in methylene chloride and concentrated to dryness twice, and then rechromatographed to afford 3.70 g of the desired product (77%). ¹ H NMR (CD₂CI₂) 57.81 (d, J = 2 Hz, 1 H, ArH), 7.77 (d, J = 7 Hz, 2H, ArH), 7.64 (d, J = 2 Hz, 1 H, ArH), 7.55 (t, J = 7 Hz, 2H, ArH), 7.48 (mult, 3H, ArH), 7.42 (t, J = 7 Hz, 1 H, ArH), 7.31 (mult, 3H, ArH), 7.23 (t, J = 8 Hz, 2H, ArH), 7.00 (d, J = 7 Hz, 2H, ArH), 2.65 (sept, J = 7 Hz, 1 H, CH(CH₃)₂), 1 .35 (d, J = 7 Hz, 3H, CH(CH₃)₂), 1 .05 (d, J = 7 Hz, 3H, CH(CH₃)₂). ¹³C NMR (CD2CI2) 5155.8, 147.09, 143.8, 140.9, 139.6, 137.6, 131 .8, 130.2, 129.0, 128.8, 128.6, 128.4, 128.31 , 128.30, 127.9, 127.8, 127.2, 126.9, 126.7, 125.4, 28.6, 23.8, 23.1 . Exact mass for C29H₂5N₃Br calc'd: 494.123; Found: 494.125, 496.122. Step 4: 4-(5'-isopropyl-[1 ,1 ':3',1 "-terphenyl]-4'-yl)-3-phenyl-5-(o-tolyl)-4H- 1 ,2,4-triazole

A catalyst solution was prepared by combining Pd₂(dba)₃ (0.43 g, 0.47 mmol) and S-Phos (0.78 g, 1 .9 mmol) in toluene (60 ml_) and stirring the mixture at room temperature. 3-Bromo-4-(5'-isopropyl-[1 ,1 ':3',1 "- terphenyl]-4'-yl)-5-phenyl-4H-1 ,2,4-triazole (4.65 g, 9.40 mmol), o- tolyloboronic acid (2.56 g, 18.8 mmol), and potassium phosphate monohydrate (6.5 g, 28.2 mmol) were dissolved in toluene (140 ml_) and the solution sparged with a stream of nitrogen. The pre-prepared catalyst mixture was added and the reaction mixture was heated to a gentle reflux, affording a red suspension. The mixture was cooled to room temperature after ~1 .5 h. It was diluted to 350 ml_ volume with ethyl acetate, filtered through a pad of Celite,® washed several times with ethyl acetate, and concentrated to afford a glassy solid. The crude product was

chromatographed on a pre-packed 340 g Biotage® silica gel column with ethyl acetate/hexane as the eluent.

The product containing fractions were combined and concentrated to dryness affording 3.82 g of a white foam (81 % yield). ¹ H NMR (CD₂CI₂) 57.73 (d, J = 7 Hz, 2H, ArH), 7.69 (s, 1 H, ArH), 7.51 (mult, 5H, ArH), 7.45 (d, J = 7 Hz, 1 H, ArH), 7.41 (t, J = 7 Hz, 1 H, ArH), 7.33 (t, J = 8 Hz, 2H, ArH), 7.26 (mult, 3H, ArH), 7.16 (t, J = 8 Hz, 2H, ArH), 6.97 (br t, J = 7 Hz, 1 H, ArH), 6.86 (d, J = 8 Hz, 1 H, ArH), 6.76 (d, J = 8 Hz, 2H, ArH), 2.69 (sept, J = 7 Hz, 1 H, CH(CH₃)₂), 2.09 (s, 3H, ArCH₃), 1 .02 (d, J = 7 Hz, 3H, CH(CH₃)₂), 0.81 (d, J = 7 Hz, 3H, CH(CH₃)₂). C NMR (CD₂CI₂) 5154.0, 153.7, 146.3, 142.8, 139.83, 139.78, 139.6, 138.4, 131 .08, 129.53, 129.48, 129.14, 128.91 , 128.88, 128.5, 128.4, 128.2, 128.1 , 127.8, 127.7, 127.6, 127.1 , 126.2, 125.5, 124.7, 28.2, 23.4, 23.3, 20.3. Exact mass for C₃6H₃₂N₃ calc'd: 506.260; Found: 506.260.

Step 5: Fac-tris (2-(4-(5'-isopropyl-[1 ,1 ':3',1 "-terphenyl]-4'-yl)-5-(o-tolyl)- 4H-1 ,2,4-triazol-3-yl)phenyl)iridium(lll) [mixture of all diastereomers], Composition B1

The solid ligand from above (1 .92 g, 3.80 mmol) and iridium tris- acetylacetonate (0.56 g, 1 .15 mmol) were premixed in a 5 dram vial under nitrogen in a glove box. The mixture was placed in the 10 ml_ capacity stainless steel laboratory pressure reactor. The mixture was equilibrated in a nitrogen atmosphere, sealed, and heated to an internal temperature of 256 °C. Heating was discontinued after 60 h at 256 - 257 °C. The reactor was allowed to cool to room temperature and then vented. It was disassembled and the reactor tube washed with -200 ml_ of EtOAc followed by -200 ml_ of CH₂CI₂. The washings were concentrated under vacuum to afford a solid.

Synthesis Examples 2-6

These examples illustrate the isolation of the four diastereomeric pairs of enantiomers of Composition B1 . The crude material from Synthesis Example 1 was

chromatographed on a Biotage^® 340 g silica gel column. The column was eluted with a gradient of 3% to 30% ethyl acetate in hexane. The chromatography showed four peaks (two major, and two relatively minor). Fractions were concentrated and then isolated products further purified as described below.

In the structures in Examples 2-6, Ar' = ortho-methylphenyl.

Synthesis Example 2

Diastereomeric pair of enantiomers B1 -a, Δ-ΡΡΡ/Λ-ΜΜΜ, shown low.

Stereochemistry at Ir center is Δ

Stereochemistry at Ir center is Λ The purest fractions centered at 7 column volumes were combined and concentrated to afford 0.12 g of yellow solid. This was recrystallized from toluene to afford 0.051 g of material. X-ray crystallography indicated that it was the Δ-ΡΡΡ/Λ-ΜΜΜ diastereomeric pair of enantiomers. ¹HNMR (CD₂CI₂) δ 7.75 (mult, 9H, ArH), 7.55 (d, J = 2 Hz, 3H, ArH), 7.50 (t, J = 8 Hz, 6H, ArH), 7.42 (t, J = 7 Hz, 3H, ArH), 7.18 (mult, 3H, ArH), 7.07 (mult, 6H, ArH), 6.97 (d, J = 7 Hz, 6H, ArH), 6.90 (mult, 9H, ArH), 6.80 (q, J = 7 Hz, 6H, ArH), 6.67 (mult, 9H, ArH), 2.73 (sept, J = 7 Hz , 3H, CH(CH₃)₂), 1 .58 (s, 9H, ArCH₃), 1 .24 (d, J = 7 Hz, 9H, CH(CH₃)₂), 1 .09 (d, J = 7 Hz, 9H, CH(CH₃)₂). The ¹ H NMR spectrum contained -0.8 equiv of toluene. UPLC-MS indicated that this material had a purity of 97%. Exact mass for CiosHgi Nglr calc'd: 1706.703 Found: 1706.696.

Synthesis Example 3

Diastereomeric pair of enantiomers B1 -b, Δ-ΜΡΡ/Λ-ΡΜΜ, shown below.

Stereochemistry at Ir center is Λ

The purest fractions centered at 7.8 column volumes were combined and concentrated to afford 0.52 g of yellow solid . This was recrystallized from toluene to afford 0.273 g of material. X-ray crystallography indicated that it was the Δ-ΜΡΡ/Λ-ΡΜΜ diastereomeric pair of enantiomers.

¹ H NMR (CD₂CI₂) 57.78-7.72 (overlapping multiplets, 6H, ArH), 7.68 (d, J = 7 Hz, 2H, ArH), 7.58 (mult, 2H, ArH), 7.53-7.37 (overlapping multiplets, 1 1 H, ArH), 7.27-7.06 (overlapping multiplets, 13H, ArH), 7.00 (mult, 5H, ArH), 6.93-6.67 (overlapping multiplets, 18H, ArH), 6.62 (d, J = 4 Hz, 2H, ArH), 6.53 (d, J = 8 Hz, 1 H, ArH), 2.78 (sept, J = 7 Hz, 1 H, CH(CH₃)₂), 2.68 (sept, J = 7 Hz, 2H, CH(CH₃)₂), 1 .83 (s, 3H, ArCH₃), 1 .66 (s, 3H, ArCH₃), 1 .58 (s, 3H, ArCH₃), 1 .29 (d, J = 7 Hz, 3H, CH(CH₃)₂), 1 .22 (d, J = 7 Hz, 3H, CH(CH₃)₂), 1 .08 (d, J = 7 Hz, 3H, CH(CH₃)₂), 1 .02 (d, J = 7 Hz, 3H, CH(CH₃)₂), 0.69 (d, J = 7 Hz, 3H, CH(CH₃)₂), 0.45 (d, J = 7 Hz, 3H, CH(CH₃)₂). The ¹H NMR spectrum contained -1 .4 equiv of toluene. UPLC-MS indicated that this material had a purity of 98.4%. Exact mass for CiosHgi Nglr calc'd: 1706.703 Found: 1706.696.

Synthesis Example 4

Diastereomeric pair of enantiomers B1 -c, Λ-ΜΡΡ/Δ-ΡΜΜ, shown below.

Stereochemistry at Ir center is Λ

Stereochemistry at Ir center is Δ

The purest fractions centered at 8.8 column volumes were combined and concentrated to afford 0.36 g of yellow solid. This was recrystallized from toluene to afford 0.296 g of material. X-ray crystallography indicated that it was the Λ-ΜΡΡ/Δ-ΡΜΜ diastereomeric pair of enantiomers.

1 H NMR (CD₂CI₂) 57.79-7.67 (overlapping multiplets, 8H, ArH), 7.58-7.39 (overlapping multiplets, 13H, ArH), 7.20-6.72 (overlapping multiplets, 35H, ArH), 6.64-6.53 (overlapping multiplets, 4H, ArH), 2.85 (sept, J = 7 Hz, 2H, CH(CH₃)₂), 2.61 (sept, J = 7 Hz, 1 H, CH(CH₃)₂), .76 (s, 3H, ArCH₃), 1 .69 (s, 3H, ArCH₃), 1 .62 (s, 3H, ArCH₃), 1 .19 (d, J = 7 Hz, 3H, CH(CH₃)₂), .00 (d, J = 7 Hz, 3H, CH(CH₃)₂), 0.94 (d, J = 7 Hz, 3H, CH(CH₃)₂), 0.82 (d, J = 7 Hz, 3H, CH(CH₃)₂), 0.76 (d, J = 7 Hz, 3H, CH(CH₃)₂), 0.52 (d, J = 7 Hz, 3H, CH(CH₃)2)- The ¹H NMR spectrum contained -1 .7 equiv of toluene. UPLC-MS indicated that this material had a purity of 98.2%. Exact mass for CiosHgi Nglr calc'd: 1706.703 Found: 1706.697.

Synthesis Example 5

Diastereomeric pair of enantiomers B1 -d, Λ-ΡΡΡ/Δ-ΜΜΜ, shown below.

Stereochemistry at Ir center is Λ

Stereochemistry at Ir center is Δ

The purest fractions centered at 1 1 column volumes were combined and concentrated to afford 0.18 g of yellow solid. This was recrystallized from EtOAc/toluene to afford 0.030 g of material. X-ray crystallography indicated that it was the Λ-ΡΡΡ/Δ-ΜΜΜ diastereome c pair of enantiomers. ¹ H NMR (CD₂CI₂) δ 7.85 (s, 3H, ArH), 7.75 (d, J = 7 Hz, 6H, ArH), 7.51 (t, J = 7 Hz, 6H, ArH), 7.46-7.41 (overlapping multiplets, 6H, ArH), 7.07 (t, J = 7 Hz, 3H, ArH), 6.97-6.89 (overlapping multiplets, 12H, ArH), 6.84-6.78 (overlapping multiplets, 12H, ArH), 6.60 (mult, 12H, ArH), 3.06 (sept, J = 7 Hz, 3H, CH(CH₃)₂), 1 .52 (s, 9H, ArCH₃), 1 .33 (d, J = 7 Hz, 9H, CH(CH₃)₂), 1 .19 (d, J = 6 Hz, 9H, CH(CH₃)₂). UPLC indicated that this material had a purity of 94.5%. Exact mass for CiosHgiNglr calc'd: 1706.703 Found: 1706.697.

Synthesis Example 6

Mixture of Diastereomeric pair of enantiomers B1 -b + B1 -c.

Fractions near 8.4 column volumes afforded 0.29 g of yellow solid This was recrystallized from EtOAc/toluene to afford 0.177 g of material. ¹ H NMR and UPLC indicated that this was mostly B1 -c, but containing approximately 7% of B1 -b. The overall purity (that is, B1 -b + B1 -c) was -100%. Synthesis Example7:

This example illustrates the preparation of Composition B2.

Step 1 : 5-(tert-butyl)-[1 ,1 '-biphenyl]-2-amine

A catalyst solution was prepared by combining Pd₂(dba)₃ (0.92 g, 1 .0 mmol) and S-Phos (1 .6 g, 3.9 mmol) in 30 ml_ of toluene under nitrogen and stirring the mixture at room temperature for 30 min. 2- Bromo-4-tert-butylaniline (23.4 g, 102.4 mmol), phenylboronic acid (19.4 g, 143 mmol) and potassium phosphate monohydrate (70.7 g, 307 mmol) were combined in 300 mL of toluene and stirred rapidly under nitrogen 40 min. The prepared catalyst mixture in 30 mL of toluene was added and the reaction mixture was stirred under nitrogen and heated to reflux. The mixture was heated at reflux for a total of 2 h and then it was cooled to room temperature under nitrogen. The mixture was diluted with 600 mL of ethyl acetate and filtered through a pad of Celite.^® The mixture was concentrated to dryness and a portion of it (17.0 g, 56%) was

chromatographed on a Biotage^® 100 g silica gel column using a gradient of 2% to 20% ethyl acetate in hexane. Product-containing fractions were combined and concentrated to afford 1 1 .1 g of the desired product as a yellow oil, which crystallized to a yellow solid upon standing (86% yield). ¹ HNMR (CD₂CI₂) δ 7.47 (mult, 4H), 7.37 (mult, 1 H), 7.18 (dd, 1 H), 7.14 (mult, 1 H), 6.73 (d, 1 H), 3.71 (br s, 2H), 1 .32 (s, 9H).

Step 2: 2-([1 ,1 '-biphenyl]-2-yl)-5-phenyl-1 ,3,4-oxadiazole

2-biphenylcarboxylic acid (15.0 g, 75.7 mmol) was dissolved in 700 mL of anhydrous THF under nitrogen. The solution was treated with diisopropylethylamine (29.4 g, 227 mmol, 3.0 equiv) followed by 2-(7-Aza~ 1 H-benzotriazoie-1 -y!) 1 .1 ,3,3-tetramethyiuronium hexafiuorophosphate (31 .7 g, 83.2 mmol) and benzoyl hydrazine (10.3 g, 75.7 mmol). The mixture was stirred under nitrogen at room temperature for 2.5 h and then it was treated with additional diisopropylethylamine (151 mmol, 2.0 equiv) followed by p-tosyl chloride (227 mmol, 3.0 equiv) added in portions. The mixture was stirred at room temperature under nitrogen overnight. The mixture was stirred and treated slowly with 21 mL of 29% aqueous ammonium hydroxide. A light yellow precipitate formed after a few min. The solid was filtered off and washed with acetonitrile. The filtrate was concentrated to afford a gold-colored colored syrup. This was suspended in 600 mL of water and extracted twice with dichloromethane. The dichloromethane extracts were combined, washed once with 500 mL of water, dried over Na₂SO , filtered, and concentrated to dryness. The resulting material was redissolved in dichloromethane and washed 5 times with 500 mL portions of water. The dichloromethane layer was dried over MgSO₄, filtered, and concentrated to afford a solid. The solid was dissolved /suspended in dichloromethane and half (by weight) was chromatographed on a Biotage® 340 g silica gel column using a gradient of 5% to 40% ethyl acetate in hexane. The product-containing fractions were combined and concentrated to a viscous pale yellow oil which was dried under high vacuum (10.3 g, 91 % yield). ¹ H NMR was consistent for the desired product containing 0.10 equiv of ethyl acetate. ¹ HNMR

(CD₂CI₂) δ 8.17 (d, 1 H), 7.65 (mult, 3H), 7.56 (dt, 1 H), 7.50 (mult, 2H), 7.43 (mult, 5H), 7.34 (mult, 2H). Step 3: 3-([1 ,1 '-biphenyl]-2-yl)-4-(5-(tert-butyl)-[1 ,1 '-biphenyl]-2-yl)-5- phenyl-4H-1 ,2,4-triazole

5-(tert-butyl)-[1 ,1 '-biphenyl]-2-amine (6.62 g, 29.4 mmol) was added to a 50 mL round flask containing a small stir bar under nitrogen. It was stirred and treated with anhydrous aluminum chloride (1 .10 g, 8.25 mmol) in small portions with stirring to afford a suspension. The mixture was stirred under nitrogen and heated to 138-140 °C; the temperature was maintained for 2 h. The mixture was then treated with a solution of 2- ([1 ,1 '-biphenyl]-2-yl)-5-phenyl-1 ,3,4-oxadiazole (3.25 g, 10.9 mmol) in 1 - methyl-2-pyrollidinone (3.3 ml_) and heated to reflux. After 67 h at reflux, the mixture was cooled to room temperature forming a solid glass. It was triturated with portions of 20% aqueous HCI and then extracted into ethyl acetate. The mixture was extracted several times with ethyl acetate and diethyl ether. The organic extracts were combined, stirred over excess solid K₂CO₃, dried over MgSO , filtered, and concentrated to afford an amber oil. The amber oil chromatographed on a Biotage 340® g silica gel column. The column was eluted with a gradient of 12% to 100% ethyl acetate in hexane. Fractions of the major product at 7.5 column volumes were combined and concentrated to afford 2.90 g of the desired product as an off-white foam (53% yield). ¹ HNMR (CD₂CI₂) δ 7.46 (d, 2H), 7.36 (t, 2H), 7.32-7.12 (overlapping multiplets, 10H), 7.02 (t, 1 H), 6.79 (t, 3H), 6.61 (d, 2H), 6.48 (d, 1 H), 5.62 (d, 1 H), 1 .31 (s, 9H).

Step 4: Fac-tris-(2-(5-([1 ,1 '-biphenyl]-2-yl)-4-(5-(tert-butyl)-[1 ,1 '-biph 2-yl)-4H-1 ,2,4-triazol-3-yl)phenyl)iridium(lll), Composition B2.

The solid ligand from above (2.88 g, 5.70 mmol) and iridium tris- acetylacetonate (0.85 g, 1 .73 mmol) were premixed in a 5 dram vial under nitrogen in the glove box. The mixture was placed in a 6.5 ml_ capacity stainless steel pressure reactor. The mixture was equilibrated in a nitrogen atmosphere, sealed, and heated to an internal temperature of 253 °C. The mixture was heated for 60 h and then allowed to slowly cool to room temperature while sealed. The reactor was opened and the contents rinsed out with approximately 200 ml_ of dichloromethane. The rinsings were concentrated and dried to afford a solid.

Synthesis Example 8

This example illustrates the isolation of a diastereomeric pair of enantiomers of Composition B2.

The crude material from Synthesis Example 7 was dissolved in dichloromethane and chromatographed on a Biotage® 340 g silica gel column. The column was eluted with a gradient of 3% to 30% ethyl acetate in hexane. The UV detector showed three broad peaks in the chromatogram.

The cleanest fractions centered at 9.3 column volumes were combined and concentrated to afford 0.07 g of a yellow glass which solidified to a yellow solid. Recrystallization from toluene/pentane afforded 0.05 g of a yellow solid. ¹ HNMR (CD₂CI₂) δ 7.39 (t, 1 H), 7.26 (mult, 1 H), 7.20-7.10 (overlapping multiplets, 3H), 7.03 (d, 1 H), 7.00-6.90

(overlapping multiplets, 4H), 6.90-6.75 (overlapping multiplets, 5H), 6.68 (t, 1 H), 6.63 (d, 2H), 6.52 (d, 1 H), 6.47 (d, 1 H), 1 .31 (s, 9H). Mass Spec showed expected parent+1 ion at m/z = 1707.6. Based on its ¹ H NMR, this material is a MMM/PPP diastereomer, with the relative configuration at Ir undetermined. The diastereomeric pair of enantiomers is either B2-a, Δ-ΡΡΡ/Λ-ΜΜΜ, or B2-d, Λ-ΡΡΡ/Δ-ΜΜΜ, shown below. By UPLC the purity of this material was 97.5%.

Stereochemistry at Ir undetermined Stereochemistry at Ir undetermined

Synthesis Example 9

This example illustrates the preparation of Composition B3.

Step 1 : 4-(3-isopropyl-[1 ,1 '-biphenyl]-2-yl)-3-phenyl-4H-1 ,2,4-triazole

2-phenyl-1 ,3,4-oxadiazole (3.25 g, 22.2 mmol) was placed in a 100 ml_ three neck flask and treated with a solution of 3-isopropyl-biphenyl-2- ylamine (4.70 g, 22.2 mmol) in 1 ,2- dichlorobenzene (4.5 ml_). The resulting solution was stirred at room temperature under nitrogen and treated with one equivalent of trifluoroacetic acid (1 .65 ml_). The mixture was stirred and heated at reflux overnight. The mixture was then cooled to room temperature and treated with excess aqueous K2CO3 forming a gummy solid precipitate. This was extracted three times with ethyl acetate. The ethyl acetate layers were combined, dried over MgSO , filtered, and concentrated to afford a semi-solid. This material was chromatographed on a Biotage^® 340 g silica gel column. The column was eluted with a gradient of 12% to 100% ethyl acetate in hexane. Fractions containing product were combined and concentrated to afford 4.07 g of the desired triazole as a white foam (yield = 54%). ¹ HNMR (CD₂CI₂) δ 8.10 (s, 1 H), 7.61 (t, 1 H), 7.55 (d, 1 H), 7.36 (mult, 1 H), 7.31 (d, 1 H), 7.30-7.20 (overlapping multiplets, 5H), 7.16 (t, 2H), 6.79 (d, 2H), 2.68 (sept, 1 H), 1 .22 (d, 3H), 1 .02 (d, 6H).

Step 2: 3-bromo-4-(3-isopropyl-[1 ,1 '-biphenyl]-2-yl)-5-phenyl-4H-1 ,2,4- triazole

A solution of the triazole synthesized above (4.07 g, 12.0 mmol) in 28 ml_ of carbon tetrachloride was treated with 28 ml_ of acetic acid. N- bromosuccinimide (3.75 g, 21 .0 mmol) was added in portions as the reaction was heated at reflux for a total of 25 h. After cooling to room temperature, the reaction mixture was concentrated on a rotary evaporator to remove most of the acetic acid and carbon tetrachloride. The residue was dissolved in ethyl acetate, and washed with excess aqueous sodium carbonate. The aqueous layer was extracted again with ethyl acetate. The ethyl acetate extracts were combined, washed once with water, washed once with brine, dried over MgSO₄, filtered and concentrated to afford a glass which slowly crystallized. This material was

chromatographed on a Biotage® 340 g silica gel column. The column was eluted with a gradient of 4% to 34% ethyl acetate in hexane. The main fractions were combined, concentrated, and dried under high vacuum to afford 4.40 g of the desired product as a white foam (yield = 88%).

1 HNMR (CD₂CI₂) δ 7.68 (t, 1 H), 7.57 (d, 1 H), 7.40-7.33 (overlapping multiplets, 4H), 7.30-7.22 (overlapping multiplets, 3H), 7.18 (t, 2H), 6.89 (d, 2H), 2.56 (sept, 1 H), 1 .26 (d, 3H), 0.96 (d, 3H). Step 3: 3-(2-ethylphenyl)-4-(3-isopropyl-[1 ,1 '-biphenyl]-2-yl)-5-phenyl-4H- 1 ,2,4-triazole

A catalyst solution was prepared by combining Pd2(dba)3 (0.24 g, 0.26 mmol) and S-Phos (0.43 g, 1 .04 mmol) in 33 mL of toluene under nitrogen and stirring the mixture at room temperature for 30 min. The bromo-triazole from above (2.20 g, 5.26 mmol), 2-ethylphenylboronic acid (1 .58 g, 10.5 mmol) and potassium phosphate monohydrate (3.64 g, 15.8 mmol) were combined in 80 mL of toluene. The mixture was stirred rapidly under nitrogen and sparged with a stream of nitrogen bubbled through the mixture for 40 min. The catalyst mixture was added and the reaction mixture was stirred under nitrogen and heated to reflux. The mixture was refluxed under nitrogen overnight. After 18 h, the mixture was cooled to room temperature under nitrogen. The reaction mixture was diluted with an equal volume (1 15 mL) of ethyl acetate and filtered through a Celite® pad. The pad was washed several times with ethyl acetate into the filtrate. The filtrate was concentrated to afford a glassy solid. The solid was chromatographed on a Biotage® 340 g silica gel column. The column was eluted with a gradient of 4% to 40% ethyl acetate in hexane. The main fractions were combined and concentrated to afford 1 .33 g (57% yield) of a pale yellow foam which crystallized to a pale yellow solid.

1 HNMR (CD₂CI₂) 5 7.59 (t, 1 H), 7.40 (d, 1 H), 7.36 (mult, 3H), 7.27 (mult, 3H), 7.22 (mult, 2H), 7.10 (t, 2H), 6.92 (mult, 1 H), 6.76 (d, 1 H), 6.65 (d, 2H), 2.59 (sept, 1 H), 2.53 (mult, 1 H), 2.38 (mult, 1 H), 1 .21 (t, 3H), 0.86 (d, 3H), 0.74 (d, 3H). Step 4: Fac-tris{(2-(5-(2-ethylphenyl)-4-(3-isopropyl-[1 ,1 '-biph

4H-1 ,2,4-triazol-3-yl)phenyl)} iridium, Composition B3.

The ligand from above (1 .33 g, 3.00 mmol) and iridium tris- acetylacetonate (0.46 g, 0.94 mmol) were premixed in a 50 mL flask under nitrogen in the glove box. The mixture was placed in a 6.5 mL capacity stainless steel pressure reactor. The vessel was sealed tightly under nitrogen. The pressure vessel was then heated over at an internal melt temperature of 248 °C for 60 h. After cooling, the crude product was chromatographed on a Biotage® 340 g silica gel column which was eluted with a gradient of 2% to 20% ethyl acetate in hexane.

Synthesis Examples 10 and 1 1

These examples illustrate the isolation of diastereomeric pairs of enantiomers of Composition B3. In the structures for Examples 10 and 1 1 , Ar' = ortho-ethylphenyl.

Synthesis Example 10

Products were isolated by concentrating product-containing fractions to dryness followed by recrystallization from toluene. This resulted in the isolation of 50 mg of a first material. ¹ HNMR (CD2CI2) δ 7.65-7.50 (overlapping multiplets, 5H), 7.37 (d, 1 H), 7.30-6.95

(overlapping multiplets, 17H), 6.94-6.71 (overlapping multiplets, 14H), 6.71 -6.50 (overlapping multiplets, 9H), 6.42 (d, 1 H), 6.38 (d, 1 H), 2.78 (sept, 1 H), 2.53 (mult, 2H), 2.40-2.20 (overlapping multiplets, 2H), 2.20- 2.00 (overlapping multiplets, 2H), 1 .69 (mult, 1 H), 1 .45 (mult, 1 H), 1 .25 (d, 3H), 1 .12 (d, 3H), 1 .08 (d, 3H), 1 .00 (t, 3H), 0.98-0.80 (overlapping multiplets, 12H), 0.58 (d, 3H), 0.29 (d, 3H). UPLC-MS indicated a purity of 99.3% (however, this includes a small shoulder peak corresponding to a trace amount of another iridium complex in which an ethyl group has been lost from one of the three ligands). Parent ion + 1 peak observed at m/z = 1521 .00. The ¹H NMR indicates that this material is one of the two possible MMP/PPM diastereomers, with the relative configuration at Ir undetermined; that is, it is either B3-c, Λ-ΜΡΡ/Δ-ΡΜΜ, or B3-b, Δ-ΜΡΡ/Λ- PMM, shown below.

Stereochemistry at Ir center undetermined

Synthesis Example 1 1

From the concentrated fraction of Synthesis Example 10, an additional 36 mg of a second product was isolated. ¹ HNMR (CD2CI2) δ 7.55 (mult, 2H), 7.21 (mult, 2H), 7.14 (d, 1 H), 7.00 (d, 1 H), 6.84 (t, 1 H), 6.80-6.69 (overlapping multiplets, 6H), 6.64 (mult, 2H), 6.58 (d, 1 H), 2.73 (sept, 1 H), 2.10 (mult, 1 H), 1 .50 (mult, 1 H), 1 .20 (d, 3H), 1 .12 (d, 3H), 0.85 (t, 3H). UPLC-MS indicated a purity of 99.7%. Parent ion + 1 peak observed at 1521 .00. This second product was determined by x-ray crystallography to be B3-a, the Λ-ΜΜΜ/Δ-ΡΡΡ diastereomeric pair of enantiomers, shown below.

Stereochemistry at Ir center is Λ Stereochemistry at Ir center is Δ

Synthesis Example 12

This example illustrates the preparation of Composition B4 and the isolation of diastereomeric pairs of enantiomers of Composition B4.

Step 1 : 4-(3-isopropyl-[1 ,1 '-biphenyl]-2-yl)-3-phenyl-5-(o-tolyl)-4H-1 ,2,4- triazole

A reaction mixture containing 3-bromo-4-(3-isopropyl-[1 ,1 '- biphenyl]-2-yl)-5-phenyl-4H-1 ,2,4-triazole (see Synthesis Example 9, Step 2, 4.40 g, 10.5 mmol), o-tolylboronic acid (2.85 g, 21 .03mmol), Pd₂dba₃ (0.288 g, 0.03 equiv), S-Phos (0.517 g, 0.12 eq.), K₃PO₄ (7.26 g, 3 equiv) in 150 ml_ of toluene was heated at reflux for 2 h under nitrogen. The reaction mixture was cooled to room temperature, and then passed through a silica gel bed. The filtrate was concentrated under reduced pressure, then purified by silica gel column chromatography (10- 30% ethyl acetate in hexane) to provide 3.7g (82%) of the triazole ligand as a white solid.

Step 2: fr/^'s-3-(2-methylphenyl)-5-phenyl-4-[3-(propan-2-yl) biphenyl-2-yl]- -1 ,2,4-triazole-iridium, Composition B4

The triazole ligand from above (1 .3g, 3.02mmol) and iridium(lll) acetylacetonate (0.5g, 0.917mmol) were added to a long neck round- bottom flask and placed in a Kugelrohr distillation apparatus. The reaction mixture was purged with nitrogen, then heated to 241 °C for 63 h under nitrogen to form a mixture including Composition B4. Step 3: Isolation of diastereomeric pairs of enantiomers

The resultant mixture from above was allowed to cool to room temperature, then dissolved in ethyl acetate. TLC showed 4 major components of mixture. By silica gel column chromatography (0-10% ethyl acetate in hexane) only two of the components were purely separated to provide two diastereomeric pairs of enantiomers as solid material.

The first compound (60mg, 4.4% yield) was determined to be B4-a, ΔΡΡΡ/ΛΜΜΜ, by X-ray crystallography. The structure is shown below, where Ar' = ortho-methylphenyl.

Stereochemistry at Ir center is Δ Stereochemistry at Ir center is Λ

The second compound (200mg, 14.8% yield) was determined to be B4-b, ΔΜΡΡ/ΛΡΜΜ, by X-ray crystallography. The structure is shown below, where Ar' = ortho-methylphenyl.

Stereochemistry at Ir center is Δ

Stereochemistry at Ir center is Λ Device Examples

These examples demonstrate the fabrication and performance of OLED devices.

(1 ) Materials

HIJ-1 is an electrically conductive polymer doped with a polymeric

fluorinated sulfonic acid. Such materials have been described in, for example, published U.S. patent applications US 2004/0102577, US 2004/0127637, US 2005/0205860, and published PCT application WO 2009/018009. HT-1 is a triarylamine-containing polymer. Such materials have been described in, for example, published PCT application

WO 2009/067419.

Host-1 is shown below

Host-2 is shown below

ET-1 is a metal quinolate complex.

The devices had the following structure on a glass substrate: anode = Indium Tin Oxide (ITO), 50 nm

hole injection layer = HIJ-1 (50 nm)

hole transport layer = HT-1 (20 nm)

photoactive layer, discussed below = 100:16 Hos dopant ratio (38 nm);

anti-quenching layer = Same as host in photoactive layer (10nm) electron transport layer = ET-1 (10 nm)

electron injection layer/cathode = CsF/AI (1 /100 nm)

(2) Device fabrication

OLED devices were fabricated by a combination of solution processing and thermal evaporation techniques. Patterned indium tin oxide (ITO) coated glass substrates from Thin Film Devices, Inc were used. These ITO substrates are based on Corning 1737 glass coated with ITO having a sheet resistance of 30 ohms/square and 80% light transmission. The patterned ITO substrates were cleaned ultrasonically in aqueous detergent solution and rinsed with distilled water. The patterned ITO was subsequently cleaned ultrasonically in acetone, rinsed with isopropanol, and dried in a stream of nitrogen.

Immediately before device fabrication the cleaned, patterned ITO substrates were treated with UV ozone for 10 minutes. Immediately after cooling, an aqueous dispersion of HIJ-1 was spin-coated over the ITO surface and heated to remove solvent. After cooling, the substrates were then spin-coated with a hole transport solution, and then heated to remove solvent. The substrates were masked and placed in a vacuum chamber. The photoactive layer, the electron transport layer and the anti-quenching layer were deposited by thermal evaporation, followed by a layer of CsF. Masks were then changed in vacuo and a layer of Al was deposited by thermal evaporation. The chamber was vented, and the devices were encapsulated using a glass lid, dessicant, and UV curable epoxy.

(3) Device characterization

The OLED samples were characterized by measuring their

(1 ) current-voltage (l-V) curves, (2) electroluminescence radiance versus voltage, and (3) electroluminescence spectra versus voltage. All three measurements were performed at the same time and controlled by a computer. The current efficiency of the device at a certain voltage is determined by dividing the electroluminescence radiance of the LED by the current density needed to run the device. The unit is a cd/A. The color coordinates were determined using either a Minolta CS-100 meter or a Photoresearch PR-705 meter.

Examples 1 -5

These examples illustrate the use of diastereomeric pairs of enantiomers from Composition B1 as the light emitting material in a device. The materials used and the results are given in Table 1 below.

Table 1 . Device results

All data @ 1000 nits. E.Q.E. is the external quantum efficiency; EL peak is the wavelength of maximum emission; CIE(x,y) are the x and y color coordinates according to the CLE. chromaticity scale (Commission Internationale de L'Eclairage, 1931 ); T70 is a measure of lifetime and is the time to reach 70% of initial luminance.

It can be seen from Table 1 that the different diastereomeric pairs of enantiomers have different physical properties.

Example 6

This example illustrates the use of a diastereomeric pair of enantiomers from Composition B2 as the light emitting material in a device.

The materials used and the results are given in Table 2 below.

Table 2. Device results¹

All data @ 1000 nits. E.Q.E. is the external quantum efficiency; EL peak is the wavelength of maximum emission; CIE(x,y) are the x and y color coordinates according to the CLE. chromaticity scale (Commission Internationale de L'Eclairage, 1931 ); T70 is a measure of lifetime and is the time to reach 70% of initial luminance. ²The dopant is a 50/50 mixture of PPP/MMM enantiomers, with the stereochemistry at Ir (Δ or Λ) undetermined.

Examples 7-8

These examples illustrate the use of diastereomeric pairs of enantiomers from Composition B3 as the light emitting material in a device.

The materials used and the results are given in Table 3 below.

Table 3. Device results¹

All data @ 1000 nits. E.Q.E. is the external quantum efficiency; EL peak is the wavelength of maximum emission; CIE(x,y) are the x and y color coordinates according to the CLE. chromaticity scale (Commission Internationale de L'Eclairage, 1931 ); T70 is a measure of lifetime and is the time to reach 70% of initial luminance. ²The dopant is a 50/50 mixture of PMM/MPP enantiomers, with the the stereochemistry at Ir (Δ or Λ) undetermined.

Examples 9-10

These examples illustrate the use of diastereomeric pairs of enantiomers from Composition B4 as the light emitting material in a device.

The materials used and the results are given in Table 4 below.

Table 4. Device results Device Dopant Host EL peak CIExy EQE T70 hrs Example nm %

9 B4-a Host-2 478 (0.205, 0.451 ) 20.2 350

10 B4-b Host-2 478 (0.205, 0.453) 24 1260

All data @ 1000 nits. E.Q.E. is the external quantum efficiency; EL peak is the

wavelength of maximum emission; CIE(x,y) are the x and y color coordinates according to the CLE. chromaticity scale (Commission Internationale de L'Eclairage, 1931 ); T70 is a measure of lifetime and is the time to reach 70% of initial luminance.

It can be seen from Table 4, that the diastereomeric pair of

enantiomers B4-b has higher efficiency and longer lifetime than the

diastereomeric pair of enantiomers B4-a.

Note that not all of the activities described above in the

general description or the examples are required, that a portion of a

specific activity may not be required, and that one or more further

activities may be performed in addition to those described. Still

further, the order in which activities are listed are not necessarily the

order in which they are performed.

In the foregoing specification, the concepts have been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of invention.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the

benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more

pronounced are not to be construed as a critical, required, or essential

feature of any or all the claims. It is to be appreciated that certain features are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, reference to values stated in ranges include each and every value within that range.

Claims

CLAIMS What is claimed is:

1 . A composition capable of being separated into

diastereomeric pairs of enantiomers, the composition having Formula I

Formula I

wherein:

Ar' is selected from the group consisting of aryl and deuterated aryl R¹ is selected from the group consisting of H, D, alkyl, silyl, aryl, and deuterated analogs thereof;

R² is different from R¹ and is selected from the group consisting of

H, D, alkyl, silyl, aryl, and deuterated analogs thereof, with the proviso that no more than one of R¹ and R² is H or D; R³ is the same or different at each occurrence and is selected from the group consisting of deuterium, alkyl, silyl, aryl, and deuterated analogs thereof;

a is an integer from 0-3; and

b is an integer from 0-4.

2. The composition of Claim 1 consisting essentially of n diastereomeric pairs of enantiomers having the same molecular formula, wherein n is 1 , 2, or 3.

3. The composition of Claim 1 , which is at least 10%

deuterated.

4. The composition of Claim 1 , wherein Ar' has Formula II

Formula II

wherein:

R⁴ is selected from the group consisting of alkyl, silyl, aryl, and deuterated analogs thereof, and

* indicates the point of attachment.

5. The composition of Claim 4, wherein R⁴ is selected from the group consisting of phenyl, C1 -10 alkyl, C3-12 silyl, and deuterated analogs thereof.

6. The composition of Claim 1 , wherein R¹ is an alkyl or deuterated alkyl having 1 -6 carbons.

7. The composition of Claim 1 , wherein R¹ is a silyl or deuterated silyl having 3-6 carbons.

8. The composition of Claim 1 , wherein R¹ is a C6-12 aryl or C6-12 deuterated aryl.

9. The composition of Claim 1 , wherein R² is an alkyl or deuterated alkyl having 1 -6 carbons.

10. The composition of Claim 1 , wherein R² is a silyl or deuterated silyl having 3-6 carbons.

1 1 . The composition of Claim 1 , wherein R² is a C6-12 aryl or

C6-12 deuterated aryl.

12. The composition of Claim 2, wherein Ar' has Formula II

Formula II

wherein:

R⁴ is selected from the group consisting of alkyl, silyl, aryl, and

deuterated analogs thereof, and

* indicates the point of attachment.

13. The composition of Claim 12, wherein R⁴ is selected from the group consisting of phenyl, C1 -10 alkyl, C3-12 silyl, and deuterated analogs thereof.

The composition of Claim 2, wherein n

15. An organic electronic device comprising a first electrical contact, a second electrical contact and a photoactive layer therebetween, the photoactive layer comprising a composition having Formula I

Formula I

wherein:

Ar' is selected from the group consisting of aryl and deuterated aryl; R¹ is selected from the group consisting of H, D, alkyl, silyl, aryl, and deuterated analogs thereof;

R² is different from R¹ and is selected from the group consisting of

H, D, alkyl, silyl, aryl, and deuterated analogs thereof, with the proviso that no more than one of R¹ and R² is H or D;

R³ is the same or different at each occurrence and is selected from the group consisting of D, alkyl, silyl, aryl, and deuterated analogs thereof;

a is an integer from 0-3; and

b is an integer from 0-4.

16. The device of Claim 15, wherein the composition having Formula I consists essentially of n diastereomenc pairs of enantiomers, where n is 1 , 2, or 3, and and wherein no additional diastereomeric pairs of enantiomers having the same chemical formula are present.

17. The device of Claim 16, wherein n = 1 .

18. The device of Claim 16, wherein n = 2.