Infrared spectra and structure of hydrogen bonds in N '-substituted isonicotinic hydrazides formed by crystallization from solution and via solid phase transformations

Crystal chemical and IR spectroscopic data for N'-substituted isonicotinic hydrazides (INH) of the general formula Py-C(=O)-N(H)-N'=C(H)-R [R = thiney l, furyl, 5-nitrofuryl, and o-nitrophenyl] have been analysed. Crystalline compounds (hydrates, solvates, solvate hydrates, salts) of a specified comp osition and structure, i.e. a desired system of intermolecular hydrogen bon ds, can be obtained by deliberately varying the solvent composition during synthesis or recrystallization. The systematic effects of substituent R on composition and structure of INH solvates and on their thermodynamic stabil ity have been revealed. (C) 1998 Elsevier Science B.V. All rights reserved.