Synthesis, Spectral and Structural Studies, and an Evaluation of the Hydrogen Bonding of Some Phenylhydrazone

Abstract

A series of 46 phenylhydrazones, soms novel, containing a variety of structural types has been synthesised. These have been studied by lH n.m.r. and i.r. spectroscopy with respect to potential inter- and intra-mslecular hydrogen bonding. ortho-Nitro or -carbony1 groups form strong hydrogen bonds to the imino-group which are readily observed by lH n.m.r. but not by i.r. spectroscopy. ' Terminal ' carbonyl groups also form strong hydrogen bonds to the imino-group and these can be detected by both i.r. and lH n.m.r. spectroscopy. When both ortho-nitro- or -carbony1 groups and ' terminal ' carbonyl groupsare present the imino hydrogen atom is doubly hydrogen bonded and this is apparent in the lH n.m.r. spectrum. The formation of an intramolecular hydrogen bond in the phenyl- hydrazone prevents the formation of an interm Aecular hydrogen bond between the phenylhydrazone and a polar solvent