Structural, spectroscopic and DFT study of 4-methoxybenzohylhydrazide Schiff bases

VERÓNICA FERRARESI-CUROTTO; GUSTAVO A. ECHEVERRÍA; OSCAR E. PIRO; REINALDO PIS-DIEZ; ANA C. GONZÁLEZ-BARÓ

SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY.

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 137 p. 692 - 700

1386-1425

A detailed structural and spectroscopic study of some Schiff bases obtained from condensation of 4-methoxybenzohydrazide with five related aldehydes, namely o-vanillin, vanillin, 5-bromovanillin, 5-chlorosalicylaldehyde and 5-bromosalicylaldehyde is reported. The crystal structures of four members of the family were determined and compared with one another. The hydrazones obtained from 5-chlorosalicylaldehyde and 5-bromosalicylaldehyde resulted to be isomorphic to each other. The solid-state structures are stabilized by an intra-molecular O-H···N interaction between the O-H moiety from the aldehyde and the hydrazone nitrogen atom, present in each of the crystal structures despite of the differences in crystal packing. A comparative analysis between experimental and theoretical results is presented. The conformational space was searched and geometries were optimized both in gas phase and including solvent effects. The structure is predicted for the compound for which the crystal structure was not determined. Infrared and electronic spectra were measured and assigned with the help of data obtained from computational methods based on the Density Functional Theory.