CS262585B1 - Luminophins of bis (4,6 diarylpyridin-2-yl) -arenes and a process for their preparation - Google Patents

Abstract

The luminophoric bis(4,6-diarylpyridin-2-yl)arenes of the general formula I, where n « = 1 to 3 and m > 0 to 3, can be used as crystalline or liquid scintillators. The method of their production consists in treating the dicinnamoylarenes of the general formula II, where n has the meaning given above, with at least a 1.5-fold stoichiometric excess of phenacylpyridinium salts of the general formula III, where m has the meaning given above, under boiling in an aprotic polar solvent in the presence of at least a ten-molar excess of ammonium salts of carboxylic acids as a condensing agent.

Description

The invention relates to luminophoric bis (4,6-diarylpyridin-2-yl) arenes of the general formula I wherein n = 1 and 3am = 0 to 2.

All of the newly prepared compounds of formula I exhibit fluorescence activity under UV light, both in crystalline state and in solution, and could therefore find use in scintillation techniques.

A process for the preparation of the luminophoric bis (4,6-diarylpyridin-2-yl) -arenes of the formula I according to the invention is characterized in that the dicinnamoylarenes of the formula II, where n is as defined above, are treated with at least a 1.5-fold stoichiometric excess wherein m is as defined above. The reaction is carried out under boiling in an aprotic polar solvent such as a mixture of acetic acid and dimethylformamide in the presence of at least a ten molar excess of ammonium salts of carboxylic acids as condensing agent.

The process for the preparation of the heterocycles of the formula I according to the invention is illustrated in the examples below.

He did

Method for the preparation of 1,4-bis / (2-biphenyl-4-yl) -4-phenyl-6-pyridyl] -benzene (Compound I, n = 1, m = 1)

0.34 g 1,4-dlnamoylbenzene (II, n = 1, 0.001 mol) was heated to boiling with 1.10 g of compound III (m = 1, 0.003 mol) in the presence of 4 g ammonium acetate in acetic acid-dimethylformamide (1: 1) for 15 hours at 180 ° C oil bath temperature. After completion of the reaction, the reaction mixture was poured into 200 ml of water and the resulting precipitate was filtered off. After drying, it was dissolved in a small amount of chloroform and chromatographed on a silica gel column (60 g) with CCl 3 -benzene 3: 1. The fraction with the highest R _f and significant luminescence under UV light was collected. Evaporation of the solvent on a rotary evaporator gave 0.385 g of a yellowish crystalline solid (56% of the theoretical yield) with a melting point of 317-320 ° C.

Example 2

Method for the preparation of 4,4-bis (2,4-diphenyl-6-pyridyl) -p-terphenyl (Compound I, n 3, m 0)

0.49 g of 4,4-dicinnamoyl-p-terphenyl (II, n 3, 0.001 mol) was heated to boiling with 0.87 g of phenalcylpyridine lumbromide (III, m - 0, 0.003 mol) in the presence of 2 9 ammonium acetate in 50 ml. ml of acetic acid-dimethylformamide (1: 1) for 28 h at an oil bath temperature of 180 ° C. Isolation of the product was carried out as in Example 1. 0.30 g of a yellowish-white crystalline solid (43% of the theoretical yield) with a melting point of 272 DEG-273 DEG C. was obtained.

Example 3

Method for preparing 4,4-bis (2-p-terphenyl-4-yl-4-phenyl-6-pyridyl) -p-terphenyl (compound I, n '

- 3, m 2)

0.40 g of 4,4-dicinnamoyl-p-terphenyl (II, n 3, 8.15x10 mol) was heated to boiling 8 1.05 g of the pyridinedinium salt III (m 2, 2.45x10 mol) in the presence of 2 g ammonium acetate in acetic acid-dimethylformamide (1: 1) for 40 hr at an oil bath temperature of 180 C. ^for isolation of the product was done as in example 1. It was obtained 0.082 6 g of product (10% of theor. yield) having a melting mp above 310 ° C.

Example 4

The luminescence properties of the prepared compounds are documented by the following table:

Fabric i Solid phase emission Toluene solution m n absorption max ^(nm > emission max ^(nm) abs. quant yield 0 1 490 334 362 0.36 1 1 402 336 367 0.56 0 2 419 290,333 371,388 0.66 1 2 405 287,333 372,390 0.58 0 3 482 336 380,399 0.75

SUBJECT OF THE INVENTION

Claims (3)

Luminophoric bis (4,6-diarylpyridin-2-yl) arenes of general formula I, wherein η = 1 to 3 and m = 0 to 2. 2. A process for the preparation of luminophoric bis (4,6-diarylpyridin-2-yl) arenes of the formula I as claimed in claim 1, wherein the dicinnamoylarenes of the formula II, wherein n is as defined above, are treated with at least a 1.5-fold stoichiometric excess. phenacylpyridinium salts of formula III, wherein m is as hereinbefore defined, boiling in an aprotic polar solvent in the presence of at least a ten molar excess of ammonium carboxylic acid salts as condensing agent. 3. A process according to claim 2 wherein the reaction is carried out in aprotic polar solvents such as a mixture of acetic acid and dimethylformamide or dimethylsulfoxide.