Effect of the orientation of the water molecules in the system of hydrogen bonds in the crystal hydrate of m-bromo-N′-(5-nitrofurylidene)benzohydrazide on its sensitivity to light

On the basis of a crystal-chemical analysis of the structure of the investigated benzohydrazides, the structural characteristics typical of light-sensitive crystal hydrates of this type were formulated: the formation of intermolecular polar chains of hydrogen bonds of the C=O...H₂O...H-N type with the water molecules; head-to-tail stacking of the molecules. It was shown that the investigated m-bromo-N-(5-nitrofurylidene)benzohydrazide forms 12 crystal hydrates. The dimeric associates of the water molecules link the benzohydrazide molecules in the stacks by hydrogen bonds. Polar chains of hydrogen bonds, along which intermolecular N O-phototransfer of a proton occur, are formed between the stacks with the participation of one of the water molecules. An assignment was made of the bands for the OH stretching vibrations of the water molecules in the investigated crystal hydrate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 567–572, March, 1990.