Водородные и галогенные связи в трииодаминобензоатах азотистых оснований

Abstract

The crystalline structures of three organic salts of triiodoaminobenzoic acid (1–3) and triiodoaminobenzoic acid monohydrate (4) are described, the structural features are established by the X-ray diffraction method. Compound 1: C20H19I6N3O6, М 1158.78; monoclinic syngony, space group Сс; cell parameters: a = 32.0782(10), b = 9.5284(3), c = 9.3745(3) Å;  = 90, β = 90,0(1),  = 90 deg.; V = 2865.35(16) Å3, Z = 4, ρcalc. = 2.684 g/cm3. Compound 2: C16H15I6N3O4, М 1074.71; monoclinic syngony, space group P21/c; cell parameters: a = 8.990(5), b = 28.541(11), c = 9.945(5) Å;  =  = 90, β = 91.23(2) deg.; V = 2551(2) Å3, Z = 4, ρcalc. = 2.798 g/cm3. Compound 3: C17H17I3N2O4, М 694.03; monoclinic syngony, space group I2/a; cell parameters: a = 36.02(2), b = 7.254(5), c = 16.468(9) Å;  =  = 90, β = 105.29(2) deg.; V = 4150(4) Å3, Z = 8, ρcalc. = 2.222 g/cm3. Compound 4: C7H6I3NO3, М 532.83; rhombic syngony, space group Iba2; cell parameters: a = 30.2146(4), b = 13.9830(2), c = 5.80740(10) Å;  = β =  = 90 deg.; V = 2453.57(6) Å3, Z = 8, ρcalc. = 2,885 g/cm3. The crystalline structure of two salts and triiodoaminobenzoic acid monohydrate is distinguished both by domination of hydrogen bonds and multiple halogen bonds. However, the 7-methylquinoline salt is devoid of halogen bonds due to peculiarities of the stack packaging of flat molecules. For two compounds (3 and 4), the features of their thermolysis by thermal analysis (in argon atmosphere) are determined: at the first stage (52 and 73 °C, respectively), the loss of crystallization water occurs; at 700 ° C under the thermolysis conditions of both compounds the decomposition product is glass carbon.