WO2008058490A1

WO2008058490A1 - Complex compounds of boric acid, salicylic acid or its derivatives and silver, method of their preparation, and a preparation containing these compounds for killing moulds, fungi and ligniperdous insects

Info

Publication number: WO2008058490A1
Application number: PCT/CZ2007/000101
Authority: WO
Inventors: Radim Hrdina; Marcela HRDINOVÁ; Ladislav Burgert; Václav BURES; Henryk Lewandowski; Romana SULÁKOVÁ
Original assignee: Kubi Spol S Ro; UNIVERZITA PARDUBICE
Current assignee: Kubi Spol S Ro; UNIVERZITA PARDUBICE
Priority date: 2006-11-15
Filing date: 2007-11-09
Publication date: 2008-05-22
Anticipated expiration: 2009-05-15
Also published as: CZ2006716A3; CZ300772B6

Abstract

Object of the invention are complex compounds of boric acid, salicylic acid or its derivatives and silver, having general formula (I), wherein X = H, NH2, NHC(=O)R, wherein the group R is H, or generally C1 to C8 alkyl, and a method of their preparation, consisting in preparing a solution of boric acid (one molar unit) and salicylic acid (two molar units) or its derivative in a polar solvent, the concentration of salicylic acid or its derivative in the solution being in the range of 0.2-50% wt., and the solution is prepared at the temperature in the range of from 0 °C to the boiling point of the polar solvent used; into this solution of boric acid and salicylic acid or its derivative in the polar solvent is added one molar unit of silver nitrate with stirring, the resulting solution is cooled to the temperature of 0-25 °C, and the formed white precipitate of the complex compound is then collected by filtration and dried at the temperature of 25-80 °C. The object of this invention is also a preparation containing these complex compounds for killing moulds, fungi and ligniperdous insects.

Description

Complex compounds of boric acid, salicylic acid or its derivatives and silver, method of their preparation, and a preparation containing these compounds for killing moulds, fungi and ligniperdous insects

Technical field

The invention relates to novel complex compounds of boric acid, salicylic acid or its derivatives and silver, method of their preparation, and a preparation containing these compounds for use against moulds, fungi and ligniperdous insects.

Background Art

Silver and its compounds are very efficient preparations against moulds and fungi or general disinfectants. The mechanism of action of silver, which is applied mainly in colloidal form, is not fully understood. As for the univalent silver compounds, it is known that the efficient concentrations of these ions begin as low as in the region of 10^~12 mol.drrr³ (for overview of silver and its compounds see e.g., Comprehensive Inorganic Chemistry, vol. 3, J. C. Bailar, Jr. et al., Eds., Pergamon Press, Oxford, 1973). Commercially available are also organometallic compounds of silver which exhibit these properties, too. They include, e.g., silver salicylate or its amino derivative silver aminosalicylate (see general formula A, wherein X = H or NH₂, respectively); another example is silver salt of sulphonamide, e.g. sulphadiazine (see formula B). Besides that, also metal-free derivatives of both series (A, B) exhibit biological effects, e.g., 4-aminosalicylic acid has strong antibacterial effects (for overview of these compounds see e.g., The Merck Index, An Encyclopedia of Chemicals, Drugs, and Biologicals, 12^th edition, Merck Research Laboratories, 1996), which can probably be ascribed to the formation of the zwitterionic form (⁺H₃N-C₆H₃(OH)-COO^~). The drawback of the compounds A and B consists in that they actually are pigments, which poorly penetrate into the substrate treated and can be easily removed from its surface.

It is also well known that boric acid or its salt, borax, are efficient preparations against ligniperdous (wood-destroying) insects; these compounds act as protecting agents against moulds, fungi and ligniperdous insects also in nature (e.g., in roots of plants). The disadvantage of both these boron compounds is that they are soluble in water, so that the protection of a material that is exposed to the action of water is not long- lasting. There also exist esters of boric acid, e.g., the ester of boric acid and glycerol, which have similar effects and are less soluble in water and readily soluble in ethanol (Sciarra, Elliot, J. Am. Pharm. Assoc. (Sci. Ed.) 49, 116 (1960)). However, their biological efficiency, particularly against moulds, is low, and the mould will be destroyed neither by boric acid nor by borax once the substrate has already been attacked by the mould.

Boric acid (H₃BO₃) is known to be a weak monoprotic acid of a limited solubility in water, which does not act as a proton donor but acts as a Lewis acid. Salicylic acid or its derivatives form tetrahedral complexes with boric acid at the ratio of 1 : 1 or 2 : 1 (see Reaction in the boric acid-salicylic acid system. Grundsteins, V., Svarcs, E., Inst. Neorg. Khim., Riga, USSR. Latvijas PSR Zinatnu Akademijas Vestis, Kimijas Serija (1978), (2), 131-5. ISSN: 0002-3248), the characteristic IR vibrations of B-O bond in the tetrahedral complex being in the range of 980-975 cm^"1. The proton in these complexes can be replaced by another cation. For instance, there is a paper describing complexes of boron and 4-methyl- or 4-hydroxysalicylic acid, in which the proton has been replaced by silver cation {Silver salts of boric acid anionic complexes with 4-methyl- and 4-hydroxysalicylic acids, Lokenbaha, M. et a/., Inst. Neorg. Khim., Riga, USSR. Latvijas PSR Zinatnu Akademijas Vestis, Kimijas Serija (1986), (6), 667-9. ISSN: 0002-3248). Furthermore, e.g., complexes of boron and salicylic acid or its derivatives (carrying as substituents halogen, alkyl, haloalkyl, aralkyl such as benzoyl and aryl) in the form of salts (with cations H⁺, Li⁺, Na⁺, K⁺, Ag⁺ etc.) are described in US patent 4 767 688 (1988), in which the compounds are used as additives to xerographic toners (Charge Control Additives).

Distinct disinfecting effects are also exhibited by cationic, i.e. basic dyestuffs, in which the chromophore carries a positive charge counterbalanced by a simple anion. The best known representatives, e.g., are Crystal violet and Gentian violet (for a toxicological study, see H. C. Hodge et a/., Toxicol. Appl. Pharmacol. 22, 1 (1972)). In micro-organisms, these compounds bind to phosphate group, thereby preventing the formation of adenosine triphosphate and, hence, the nutrition of the cell. All tetraalkyl- or tetraaryl-ammonium compounds, i.e. all basic dyestuffs, show this mechanism of action (for an overview of basic dyestuffs, see Colour Index, the 4^th edition on Line, The Society of Dyers and Colourists). A drawback of these ammonium compounds generally consists in their good solubility in water; therefore, they can be washed out from the material treated by the action of water. In addition, these compounds are not much resistant to environmental effects (oxidation, decomposition by light etc.) and so they do not provide any long-term protection. Ammonium compounds are not efficient pesticides against ligniperdous insects.

Hence, the drawback of the solutions known so far consists either in the insolubility of the active components and the prevention of the saturation of the material treated, or - on the contrary, - in their high solubility and readily washing out from the material treated. In addition, individual components possess specific activities, i.e. they are only efficient against some kinds of pest microorganisms, as described herein above. These drawbacks are overcome by the preparation described in this present invention.

Disclosure of Invention

Object of the present invention are new complex compounds of boric acid, salicylic acid or its derivatives and silver of general formula I,

wherein X = H, NH₂, NHC(=O)R, wherein the group R is H, or generally Ci to C₈ alkyl.

Object of the invention is further a method of preparation of the complex compound of general formula I, consisting in preparation of a solution of one molar unit of boric acid and two molar units of salicylic acid or its derivative in a polar solvent under stirring, whereas the concentration of salicylic acid or its derivative in the solution is in the range of 0.2-50 % wt. and the solution is prepared at the temperature ranging from 0 ⁰C to the boiling point of the polar solvent used, then one molar unit of silver nitrate is added with stirring into the solution of boric acid and salicylic acid or its derivative, and the resulting solution is cooled to the temperature of 0-25 ⁰C, and the formed precipitate of the complex compound is then collected by filtration and dried at the temperature of 25-80 ⁰C.

In a preferred embodiment, the solution of boric acid and salicylic acid or its derivative in the polar solvent is prepared at room temperature.

In a preferred embodiment, the polar solvent is selected from the group comprising water, ethanol, propan-1-ol, propan-2-ol, acetone or their mixtures.

In a preferred embodiment, silver nitrate is added in the form of a solution having the silver nitrate concentration in the range of 0.2-91 % wt. in a solvent selected from the group comprising water, ethanol or their mixtures, prepared at the temperature ranging from 0 ⁰C to the boiling temperature of the solvent used. Preferably, the solution of silver nitrate is prepared at room temperature.

In another preferred embodiment of the invention, silver nitrate is added in the form of a solid substance.

Object of the invention is further a preparation for killing moulds, fungi and ligniperdous insects, which contains as an active agent at least one complex compound of general formula I, solvents and optionally suitable auxiliary substances.

The above described compounds of general formula I are insoluble in water. On the other hand, they are soluble in mixtures of water and alcohol, the solubility in alcohol being the higher, the longer the aliphatic chain R is. Hence, they are applied in the form of these solutions, wherein the active agent (complex compound I) penetrates by diffusion into the material treated. After a certain period of time, the complex compound I is gradually decomposed and silver is produced by the reduction (ethanol acts on Ag⁺ as a reducing agent); the silver in atomic form is then evenly distributed throughout the material, which brings very high biological efficiency with it. Of course, silver is also insoluble in water; therefore, it cannot be washed out from the treated material by water or by organic solvents. Boric acid and salicylic acid or its derivative has fungicidal effects in the material treated, too. Thus, the preparation acts not only as a preventive protection of the material, but also as a highly efficient killer of harmful micro-organisms.

In a preferred embodiment, the preparation according to this invention contains a mixture of water and C₂ to C₃ alcohol as the solvent.

In a preferred embodiment, the preparation according to this invention contains dyestuffs and stabilisers as accompanying substances. Preferably, a dyestuff exhibiting disinfectant effects, e.g., a basic dyestuff such as, e.g., Crystal violet or Malachite green, is used.

In a preferred embodiment, the preparation according to this invention can be stabilised by an addition of hydrogen peroxide. Hydrogen peroxide prevents the reduction and the formation of silver in the solution. This preferred preparation is prepared by first preparing the required hydrogen peroxide solution in water and then adding alcohol and finally adding the complex compound of general formula I.

In a preferred embodiment, the preparation of this invention contains 0.001- 10 % wt. of the complex compound of general formula I, 25 - 98 % wt. of C₂ to C₃ alcohol, and 2 - 75 % wt. of water, and optionally further auxiliary substances, such as dyestuffs and stabilisers.

Preferably, the preparation of this invention further contains 0.01 - 5 % wt. of a dyestuff.

Preferably, a dyestuff exhibiting disinfecting effects, e.g., a basic dyestuff such as, e.g., Crystal violet or Malachite green can be used as the dyestuff.

In a preferred embodiment, the preparation of this invention can be stabilised by the addition of up to 0.6 % wt. of hydrogen peroxide, with regard to the weight of water in the preparation.

The preparation according to this invention can be used, e.g., for killing of moulds in households, or for preventive protection of wood, plaster or other materials that can be attacked by moulds, fungi or ligniperdous (wood-destroying) insects. The colourless preparation can be advantageously used for protection of plaster before decorating the walls or for protection of wood before coating with coloured coating composition itself. Examples

The ¹H and ¹³C NMR spectra were measured with Bruker AVANCE 500 apparatus in VUOS a.s., Pardubice, at 500.13 MHz (¹H) and at 125.76 MHz (¹³C), respectively. The ¹¹B NMR spectra were measured with Bruker AMX 360 apparatus at 115.55 MHz. The samples were dissolved in DMSO-D₆. The ¹H and ¹³C chemical shifts have been referenced to the solvent signals, (δ = 2.55 (¹H), and 39.6 (¹³C), resp.). The ¹¹B chemical shifts have been referenced to external B(OCH₃)₃ placed in a coaxial capillary (5(¹¹B) = 18.1). The ¹H and ¹³C chemical shifts were assigned by means of two-dimensional spectra (¹H₁ ¹H-COSY, ¹H₁ ¹³C-HSQC and ¹H₁ ¹³C-HMBC).

The infrared spectra were measured with FTIR - 8400S Fourier Transform Infrared Spectrophotometer Shimadzu. The samples were measured in solid state as KBr tablets. Approximately 20 mg sample and 60 mg KBr was ground in an agate mortar and compressed in a hydraulic press.

Example 1

Preparation of complex 1-1 ; reaction medium: water/ethanol

Silver nitrate (17 g, M = 169.87) is dissolved at room temperature (25 ⁰C) in 80 g distilled water. In another vessel, boric acid (6.18 g, M = 61.83) and salicylic acid (27.6 g, M = 138.12) are dissolved in 12O g denatured ethanol at room temperature. The silver nitrate solution is poured into the latter solution with stirring. After another 20 min of stirring, the reaction mixture is cooled to 5 ⁰C, and the formed snow-white precipitate is collected by filtration and dried at 40 ⁰C. Yield 35.8 g complex compound of formula 1-1 (C₁₄H₈O₆AgB, M = 390.89), which represents 91.6 % of the theoretical yield.

Example 2 Preparation of complex 1-1 ; reaction medium: water

In a reaction vessel, boric acid (6.18 g, M = 61.83) and salicylic acid (27.6 g, M = 138.12) are dissolved in 120 cm³ distilled water at room temperature. The mixture is heated to 80 ⁰C, and solid silver nitrate (17 g, M = 169.87) is added to the solution with stirring. After another 20 min of stirring, the reaction mixture is cooled to 20 ⁰C, and the formed snow-white precipitate is collected by filtration and dried at 40 ⁰C. Yield 35.7 g complex compound of formula 1-1 (C₁₄H₈O₆AgB, M = 390.89), which represents 91.3 % of the theoretical yield.

Elemental analysis of complex compound 1-1

The formation of the complex compound 1-1 was confirmed by infrared spectroscopy, showing in the spectrum new peaks with frequencies 999 and 970 crrf¹ v(B(OX)₄)^" _as, characteristic of tetragonal arrangement. The below-given IR spectrum was identical for samples of complex compounds 1-1 prepared according to both Example 1 and Example 2.

FTIR (KBr): 1659 crrf¹ v(C=O), 1609 crrf¹ v(C=C), 1468 cm^"1 v(C-H), 1348 cm^"1 δ(O- H) + v(C-O), 1269 cm^"1, 1244 cm^"1, 1136 crrf¹ δ(O-H) + v(C-O), 1060 cm^"1 v(C-O), 999 cm^"1 and 970 cm^"1 V(B(OH)₄-) _as, 876 cm^"1, 825 cm^"1, 770 cm^"1 δ(C-H), 754 cm^"1 and 694 cιτf ¹ δ(O-H).

Moreover, the structure of the complex compound 1-1 was confirmed by NMR spectroscopy.

Salicylic acid:

¹H NMR: 6.94 m (1H, H-6); 6.98 m (1H, H-4); 7.52 m (1H, H-5); 7.84 m (1H, H-7);

11.3 bs (1 H₁ COOH).

¹³C NMR: 113.1 (C-2); 117.3 (C-4); 119.3 (C-6); 130.5 (C-7); 135.8 (C-5); 161.5 (C-3); 172.3 (C-1).

Complex compound 1-1:

¹H NMR: 6.89 m (1 H, H-3); 6.94 m (1 H, H-6); 7.48 m (1 H, H-5); 7.80 m (1H, H-7). ¹³C NMR: 115.5 (C-2); 118.1 (C-4); 118.9 (C-6); 129.3 (C-7); 134.8 (C-5); 159.1 (C-3);

163.9 (C-1). 5(¹¹B) = 3.1.

Example 3

Synthesis of complex compound I-2; reaction medium: water/ethanol

At room temperature (25 ⁰C), AgNO₃ (17 g, M = 169.87) is dissolved in 80 g distilled water. In another reaction vessel, H₃BO₃ (6.18 g, M = 61.83) and 4-aminosalicylic acid (30.6 g, M = 153.13) are dissolved in 120 g denatured ethanol at the temperature of 75 ⁰C. The aqueous solution of AgNO₃ is poured into this solution with stirring. The reaction mixture is stirred for 30 min, then it is cooled to 5 ⁰C, and the formed greyish precipitate is collected by filtration and dried at 40 ⁰C. Yield 41.1 g complex compound of formula I-2 (C₁₄Hi₀N₂O₆AgB, M = 420.92), which represents 98 % of the theoretical yield.

Example 4 Synthesis of complex compound 1-2; reaction medium: water

In a reaction vessel, H₃BO₃ (6.18 g, M = 61.83) and 4-aminosalicylic acid (30.6 g, M = 153.13) are dissolved in 120 cm³ distilled water at room temperature. The mixture is heated to 80 ⁰C, and solid AgNO₃ (17 g, M = 169.87) is added to the solution with stirring. After another 20 min of stirring, the reaction mixture is cooled to 20 ⁰C, and the resulting greyish precipitate is collected by filtration and dried at 40 ⁰C. Yield: 40 g complex compound of formula I-2 (C₁₄H₈O₆AgB, M = 390.89), which represents 95 % of the theoretical yield.

Elemental analysis of complex compound I-2

Element % C % H % N % Ag % B

Calculated 39 .91 2. 38 6. 35 25.62 2. 57

Complex I-2, prepared 38. 83 ± 0. 02 2. 30 + 0. 02 6.72 + 0. 04 21.2 2. 34 according to Example 3

Complex I-2, prepared 35. 38 + 0. 04 2. 12 + 0. 07 6.50 + 0. 05 23.25 2. 07 according to Example 4

The formation of complex compound I-2 was confirmed by infrared spectroscopy, showing new peaks in spectrum, with frequencies 991 and 968 crrf¹ v(B(OX)₄)^" _as, characteristic of tetragonal arrangement. The below-given IR spectrum was identical for samples of complex compounds I-2 prepared according to both Example 3 and Example 4.

FTIR (KBr): 3484 cm^"1 and 3311 cιτf¹ v(NH₂), 1682 cm^"1 v(C=O), 1600 cm^"1 v(C=C- C) + δ(NH), 1462 cm^"1 v(C-H), 1323 cm^"1 δ(O-H) + v(C-O), 1304 cm^"1 v(C-N), 1146 cm^'1 δ(O-H) + v(C-O), 1068 crrf¹ v(C-O), 991 cm^"1 and 968 cm^"1 v(B(OH)₄r_as, 879 cm^"1, 849 cm^"1, 769 cm^"1, 764 cm^"1 and 694 cm^"1 δ(O-H).

Moreover, the structure of complex compound I-2 was confirmed by NMR spectroscopy.

Complex compound I-2:

¹H NMR: 5.41 bs (2H, NH₂); 6.03 d (1 H, H-4); 6.20 dd (1 H, H-6); 7.48 d (1 H, H-7). ¹³C NMR: 101.3 (C-4): 104.9 (C-2); 107.1 (C-6); 130.7 (C-7); 153.9 (C-5); 160.9 (C-3);

164.7 (C-1). δ (¹¹B) = 2.9

Example 5

Synthesis of 4-acetamido-2-hydroxybenzoic acid

4-Amino-2-hydroxybenzoic acid (7.66 g; M = 153.14; 0.05 mol) is mixed with 50 cm³ water; the pH value is adjusted to 6 by the addition of 10% aqueous solution of NaOH at formation of a solution. Acetic anhydride (7.1 cm³; M = 102.09; d = 1.081 ; n = 0.075 mol) is gradually added to this solution, the individual portions being about 0.5 cm³. The reaction temperature is kept at 60 ⁰C, and the pH value is kept at 6-7 throughout the reaction by additions of the 10% aqueous solution of NaOH. The reaction lasts 5 hours, and the progress of acetylation is monitored by means of the test with the Ehrlich reagent. After the reaction is finished, the reaction mixture is cooled to room temperature and the pH value is lowered to 3.5 by adding concentrated (35%) HCI. The precipitate formed is collected by suction (on a Bϋchner funnel), the filter cake is redissolved in 20 cm³ acetone, intensively stirred for the period of 20 min, and again precipitated by the addition of water, filtered again, and dried at the temperature of 40 ⁰C. Yield: 8.84 g chromatographically pure product (C₉H₉NO₄; M = 195.18), which represents 90.58 % of the theoretical yield.

TLC: stationary phase: ALUGRAM SIL G/UV₂₅₄ (MACHEREY-NAGEL), mobile phase: propan-2-ol / propan-1-ol / ethyl-acetate / water = 2/4/1/3 vol. parts.

The formation of the Λ/-acetyl derivative was confirmed by infrared spectroscopy, indicating the disappearance of vibration v(N-H) 3495 cm^"1 and the appearance of peaks characteristic of the secondary amine, namely 1672 cm^""1 v(C=O) Amide I and 1539 cm^"1 v(N-H) Amide II. FTIR (KBr): 3312 crrf¹ v(N-H), 1672 cm^"1 v(C=O) Amide I₁ 1651 cm^"1 v(C=O) in carboxyl group, 1599 crrf¹ v(C=C-C) + δ(NH), 1539 crrf¹ v(N-H) Amide II, 1456 cm^"1 v(C-H), 694 cm^"1 δ(O-H).

Example 6

Synthesis of complex compound I-3; reaction medium: acetone/water

4-Acetamido-2-hydroxybenzoic acid (3.9 g; M = 195.18; 0.02 mol) together with H₃BO₃ (0.62 g, M = 61.83; 0.01 mol) are dissolved in 50 cm³ acetone with addition of 4 cm³ water. Into this solution, solution of AgNO₃ (1.7 g; M = 169.87; 0.01 mol) in 5 cm³ water. The reaction mixture is stirred first at room temperature (25 ⁰C) for 1 hour and then at 35 °C again for 1 hour. A white-grey precipitate gradually separates from the reaction mixture. Finally, the reaction mixture is cooled to 0-5 °C, and the precipitate of the complex compound I-3 is collected by filtration and dried at the temperature of 40 ⁰C. Yield of complex compound I-3 (C₁₈H₁₄N₂O₈AgB, M = 504.99) is 1.63 g, which represents 32 % of the theoretical yield.

The formation of the complex compound I-3 was confirmed by infrared spectroscopy, showing new peaks in the spectrum at the frequencies of 874 and 834 cm^"1 v(B(OX)₄r_as characteristic of tetragonal arrangement.

FTIR (KBr): 3275 cm^'1 v(N-H), 1668 cm^"1 v(C=O) Amide I, 1593 cm^"1 v(C=O) in carboxyl group, 1550 cιτf¹ v(C=C-C) + δ(NH), 1539 cm^"1 v(N-H) Amide II, 1497 crrf¹, 1431 cm^"1, 1377 cm^"1, 1165 cm^"1, 874 and 834 cm^"1 v(B(OX)₄r_as and 694 cm^"1 δ(O- H). Example 7

Synthesis of 4-hexanoylamino-2-hydroxybenzoic acid

4-Amino-2-hydroxybenzoic acid (7.66 g; M = 153.14; 0.05 mol) is mixed with 50 cm³ water, the pH value is adjusted to 6 by addition of 10% aqueous solution of NaOH yielding a solution. Hexanoic acid (6.78 cm³; 0.055 mol; M = 116.16; d = 0.93) together with 7.63 cm³ triethylamine (0.055 mol; M = 101, d = 0.728) are dissolved in 25 cm³ acetone and cooled to 0 ⁰C. The hexanoic acid is activated by addition of 5.24 cm³ ethyl chloroformate (0.055 mol; M = 108.52; d = 1.139). After 5 min intensive stirring mixture at the low temperature, the reaction mixture is filtered through a sintered glass filter No. 2, the filter cake is washed with 20 cm³ acetone and transferred into the pre- prepared solution of 4-amino-2-hydroxybenzoic acid. The reaction mixture is stirred at room temperature for 30 min. The reaction then continues at the temperature of 60 ⁰C for another 3 hours. After the end of the reaction, which is determined by means of the test with the Ehrlich reagent, the pH value is decreased from 6 to 3.0 by addition of concentrated (35%) HCI. The formed precipitate is collected by suction on a Bϋchner funnel. The filter cake is mixed with 20 cm³ acetone and after 20-min intensive stirring, the product is again precipitated by the addition of distilled water, again filtered and dried at the temperature of 40 ⁰C. The yield of chromatographically pure product is 10.23 g (C₁₃H₁₇NO₄; M = 251.28), which represents 81.42 % of the theoretical yield. TLC: stationary phase: ALUGRAM SIL G/UV₂₅₄ (MACHEREY-NAGEL), mobile phase: propan-2-ol / propan-1-ol /ethyl acetate / water = 2/4/1/3 vol. parts.

The formation of the Λ/-hexanoyl derivative was confirmed by infrared spectroscopy, showing the disappearance of the vibration v(N-H) at 3495 cm^"1 and the appearance of characteristic vibrations of alkyl chain at 2983 cm^"1 v(CH₃)_as, 2962 cm^"1 v(CH₂)_as , 2860 cm^"1 v(CH₃)_s and the peaks specific to secondary amines at 1672 cm^"1 v(C=O) Amide I and 1539 cm^"1 v(N-H) Amide II.

FTIR (KBr): 3312 cm^"1 v(N-H), 2983 cm^"1 v(CH₃)_as, 2962 cm^"1 v(CH₂)_as, 2860 cm^"1 v(CH₃)_s, 1672 cm^"1 v(C=O) Amide I, 1651 cm^"1 v(C=O) in carboxyl group, 1599 cm^"1 V(C=C-C) + δ(NH), 1539 crτT¹ v(N-H) Amide II, 1456 cm^"1 v(C-H), 783 cm^"1 ω(CH₂), 694 cm^"1 δ(O-H).

Example 8

Synthesis of complex compound I-4; reaction medium: ethanol/water

4-Hexanoylamino-2-hydroxybenzoic acid (2.51 g; M = 251.28; 0.01 mol) together with H₃BO₃ (0.31 g; M = 61.83; 0.005 mol) are dissolved in 20 cm³ ethanol. Into this solution, a solution of AgNO₃ (0.85 g; M = 169.87; 0.005 mol) in 5 cm³ ethanol and 1 cm³ water is added. The reaction mixture is stirred first at room temperature (25 °C) for the period of 10 min, and then at the temperature of 60 ⁰C for another 20 min. A white- grey precipitate gradually separates from the reaction mixture. Finally, the reaction mixture is cooled to the temperature of 0 - 5 ⁰C, the precipitate of the complex compound I-4 is collected by filtration and dried at the temperature of 40 °C. The yield of the complex compound I-4 (C₂₆H₃₀N₂O₈AgB, M = 617.21) is 1.55 g, which represents 50.2 % of the theoretical yield.

The formation of the complex compound I-4 was confirmed by infrared spectroscopy, showing new peaks in the spectrum at the frequencies of 871 and 835 cm^"1 V(B(OX)₄)^" as characteristic of tetragonal arrangement.

FTIR (KBr): 3286 cm^"1 v(N-H), 2953 cm^"1 v(CH₃)_as, 2930 cm^"1 v(CH₂)as, 2870 cm^"1 v(CH₃)s, 1664 cm^"1 v(C=O) Amide I₁ 1593 cm^"1 v(C=O) in carboxyl group, 1550 cm^"1, 1523 cm^"1, 1497 cm^"1, 1434 cm^"1 v(C-H) scissoring vibration, 1373 cm^"1, 871 and 835 cm^"1, 783 cm^"1 ω(CH₂), 694 cm^"1 δ(O-H).

Example 9 Preparation P1-1

50 g of denatured ethanol (96 % of ethanol) is mixed with 50 g water, and 0.4 g complex compound of silver of the formula 1-1 is dissolved in this mixture with stirring. The resulting solution is very suitable for eradication (killing) of moulds in households (e.g. on damp walls) or for preventive protection of wood, e.g. window frames. The liquid preparation must be consumed within 24 hours after mixing the components. The content of silver in the preparation is 0.094 g, which is 0.0936 % wt., with regard to the overall mass of the preparation. The content of boron in the preparation is 0.01024 g (i.e. 0.0102 % wt.). The above-mentioned elements were determined by atomic emission photometry with inductively coupled plasma (Laboratory of atomic spectrometry, Faculty of chemical technology, University of Pardubice).

Example 10 Preparation P1-2

A mixture of 40 g water and 10 g 3% H₂O₂ is prepared and 50 g denatured ethanol (96%) is added, then 0.4 g complex compound of silver of the formula 1-1 is dissolved in this mixture with stirring. The resulting solution is very suitable for eradication (killing) of moulds in households (e.g. on damp walls) or for preventive protection of wood, e.g. window frames. The preparation is also very suitable as disinfectant. It is suitable to consume the liquid preparation within 2 years after mixing the components. The content of silver in the final preparation is 0.0936 % wt., relative to the overall mass of the preparation. The content of boron in the preparation is 0.0102 % by wt.

Example 11 Preparation P 1-3

50 g of denatured alcohol (96 % ethanol content) is mixed with 50 g water, and 0.4 g complex compound of silver of the formula 1-1 and 0.01 g Crystal violet (Cl 42555) is dissolved in this mixture with stirring. The resulting solution is very suitable for preventive protection of wood, e.g., wood constructions. The liquid preparation must be consumed within 24 hours after mixing the components. The content of silver in the preparation is 0.0936 % wt., with regard to the whole mass of the preparation. The content of boron in the preparation is 0.0102 % wt.

Example 12 Preparation P2-1

50 g denatured alcohol (96 % ethanol content) is mixed with 50 g water, and 0.4 g complex compound of silver of the formula I-2 is dissolved in this mixture. The resulting solution is very suitable as disinfectant for use in rooms with additional occurrence of fungi and moulds, preferably before decorating the walls. The liquid preparation must be consumed within 24 hours after mixing the components. The content of silver in the preparation is 0.0768 g, which represents 0.0765 % wt, with regard to the overall mass of the preparation. The content of boron is 0.01024 g (i.e. 0.01 % wt.).

Example 13 Preparation P2-2

50 g denatured alcohol (96 % ethanol content) is mixed with 50 g water, and 0.1 g complex compound of silver of the formula 11-1 and 0.01 g Malachite green (Cl 42000) is dissolved in this mixture with stirring. The resulting solution is very suitable for preventive protection of plasters before decorating the walls. The liquid preparation must be consumed within 24 hours after mixing of the components. The content of silver in the preparation is 0.025 % wt., with regard to the overall mass of the preparation. The content of boron is 0.0025 % wt.

Example 14 Preparation P3-1

50 g denatured alcohol (96 % ethanol content) is mixed with 50 g water, and 0.4 g compound of silver of the formula I-3 is dissolved in this solution. The resulting solution is very suitable as disinfectant of rooms with additional occurrence of moulds and fungi, preferably before decorating the walls. The liquid preparation must be consumed within 24 hours after mixing of the components. The content of silver in the preparation is 0.085 g, which represents 0.085 % wt., with regard to the overall mass of the preparation. The content of boron in the preparation is 0.0085 g (i.e. 0.0085 % by wt.).

Example15 Preparation P3-2

90 g denatured alcohol (96 % ethanol content) is mixed with 10 g water, the complex compound of silver of the formula I-3 (0.05 g) is dissolved in this solution. The resulting solution is very suitable for protection of thin wooden materials, e.g., plywood, or brown paper for packaging industrial goods. The liquid preparation must be consumed within 24 hours after the mixing of the components. The content of silver in the preparation is 0.01 g, which represents 0.01 % wt., with regard to the overall mass of the preparation. The content of boron in the preparation is 0.001 g (i.e. 0.001 % wt.).

Example 16 Preparation P4-1

90 g denatured ethanol (96 % ethanol content) is mixed with 10 g water, and 0.2 g of the complex compound of silver having formula I-4 and 0.01 g Crystal violet (Cl 42555) are dissolved in this solution with stirring. The resulting solution is very suitable for preventive protection of wood constructions, e.g. window frames, before applying the coating composition. The liquid preparation must be consumed within 24 hours after mixing of the components. The content of silver in the preparation is 0.035 g, which represents 0.035 % wt., with regard to the overall mass of the preparation. The content of boron in the preparation is 0.0035 g (i.e. 0.0035 % wt.).

Claims

1. Complex compounds of boric acid, salicylic acid or its derivatives and silver of general formula I₁

wherein X = H, NH₂, NHC(=O)R, wherein the group R is H, or generally C₁ to C₈ alkyl group.

2. A method of preparation of the complex compound of general formula I, characterized in that a solution of one molar unit of boric acid and two molar units of salicylic acid or its derivative in a polar solvent is prepared with stirring, wherein the concentration of salicylic acid or its derivative in the solution is in the range of 0.2-50 % wt., and the solution is prepared at the temperature ranging from 0 °C to the boiling point of the polar solvent, then one molar unit of silver nitrate is added with stirring into the solution of boric acid and salicylic acid or its derivative, and the resulting solution is cooled to the temperature of 0 - 25 ⁰C, and the formed precipitate of the complex compound is then collected by filtration and dried at the temperature of 25 - 80 ⁰C.

3. The method according to claim 2, characterized in that the solution of boric acid and salicylic acid or its derivative in polar solvent is prepared at room temperature.

4. The method according to claim 2 or 3, characterized in that the polar solvent is selected from the group comprising water, ethanol, propan-1-ol, propan-2-ol, acetone or their mixtures.

5. The method according to any of claims 2 to 4, characterized in that silver nitrate is added in the form of a solution having the silver nitrate concentration in the range of 0.2-91 % wt. in a solvent selected from the group comprising water, ethanol, or their mixtures, prepared at the temperature in the range of from 0 ⁰C to the boiling point of the solvent used.

6. The method according to claim 5, characterized in that the solution of silver nitrate is prepared at room temperature.

7. The method according to any of claims 2 to 4, characterized in that silver nitrate is added in the form of solid substance.

8. A preparation for killing moulds, fungi and ligniperdous insects, characterized in that the formulation contains as the active component at least one complex compound of general formula I, solvents and optionally suitable auxiliary substances.

9. The preparation according to claim 8, characterized in that it contains mixture of water and C₂ to C₃ alcohol as the solvent.

10. The preparation according to claims 8 or 9, characterized in that it contains dyestuffs and stabilisers as the auxiliary substances.

11. The preparation according to claim 10, characterized in that the dyestuff is a basic dyestuff.

12. The preparation according to claim 11 , characterized in that the basic dyestuff is Crystal violet or Malachite green.

13. The preparation according to claim 10 , characterized in that the stabiliser is hydrogen peroxide.

14. The preparation according to claim 9, characterized in that the preparation contains 0.001-10 % wt. of the complex compound of general formula I, 25-98 % wt. of C₂ to C₃ alcohol and 2-75 % wt. of water, and optionally auxiliary substances.

15. The preparation according to claim 14, characterized in that it contains dyestuffs and stabilizers as the auxiliary substances.

16. The preparation according to claim 15, characterized in that it also contains 0.01- 5 % by wt. of a dyestuff.

17. The preparation according to claim 16, characterized in that the dyestuff is a basic dyestuff.

18. The preparation according to claim 17, characterized in that the basic dyestuff is Crystal violet or Malachite green.

19. The preparation according to any of claims 15 to 18, characterized in that it contains up to 0.6 % wt. of hydrogen peroxide, with regard to the weight of water in the formulation.