Structural, spectroscopic and DFT study of 4-methoxybenzohydrazide Schiff bases. A new series of polyfunctional ligands

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

Five Schiff bases obtained from condensation of 4-methoxybenzohydrazide with related aldehydes,namely o-vanillin, vanillin, 5-bromovanillin, 5-chlorosalicylaldehyde and 5-bromosalicylaldehyde wereprepared. A detailed structural and spectroscopic study is reported. The crystal structures of four mem-bers of the family were determined and compared with one another. The hydrazones obtained from5-chlorosalicylaldehyde and 5-bromosalicylaldehyde resulted to be isomorphic to each other. Thesolid-state structures are stabilized by intra-molecular OAHÁ Á ÁN interactions in salicylaldehyde deriva-tives between the OAH moiety from the aldehyde and the hydrazone nitrogen atom. All crystals arefurther stabilized by inter-molecular H-bonds mediated by the crystallization water molecule. A compar-ative analysis between experimental and theoretical results is presented. The conformational space wassearched and geometries were optimized both in gas phase and including solvent effects. The structure ispredicted for the compound for which the crystal structure was not determined. Infrared and electronicspectra were measured and assigned with the help of data obtained from computational methods basedon the Density Functional Theory.