The supramolecular architecture of 4-aminoacetophenone (1-(4-fluorophenyl)ethylidene)hydrazone hydrate. Double T-contacts and extremely low-density water layers in a mixed azine

Abstract

The crystal structure of unsymmetrical azine 4-aminoacetophenone (1-(4-fluorophenyl)ethylidene)hydrazone hydrate, 1·H2O, was determined. Comparison to the X-ray structures of the symmetrical 4-fluoro- and 4-aminoacetophenone azines, 2 and 3, respectively, reinforces the view of the azine bridge as a conjugation stopper. The focus of the analysis lies with the supramolecular architecture. The structure demonstrates azines as double T-contact synthons and suggests that novel L-type arene-arene contacts also might play a significant role in the supramolecular architecture. The absence of inter-water hydrogen bonding in an extremely low-density water layer is one of the surprising and unique features of the solid-state structure of the title compound. The water layers connect azine layers through a hydrogen bonded network which is described by graph set analysis.Key words: arene-arene interaction, hydrogen bonding, graph set analysis, azine, supramolecular synthon, low density water monolayer.