Preparation, characterization, electrochemical studies and crystal structure determination of salicylaldehyde–aroylhydrazone, ferrocenyl–aroylhydrazone and salicylaldehyde–ferrocenoylhydrazone complexes of indium

Abstract

The reaction of triethylindium with salicylaldehyde–aroylhydrazone, C 6H 4( o-OH)CHNNHC(O)C 6H 4X (X= p-H, p-OCH 3, p-NO 2, m-NO 2, o-OH), yields the tetrahydrofuran (THF) adduct of (C 14H 9N 2O 2X) 2InC 2H 5. With formylferrocenyl–aroylhydrazones C 5H 5FeC 5H 4CHNNHC(O)C 6H 4X (X= p-H, p-OCH 3, p-NO 2, m-NO 2, p-Cl, o-Cl), the diethylindium–hydrazone complex, (C 18H 14N 2OFeX)In(C 2H 5) 2, was formed. With salicylaldehyde–ferrocenoylhydrazone, C 6H 4( o-OH)CHNNHC(O)C 5H 4FeC 5H 5, the monohydrazone complex (C 18H 15N 2O 2Fe)In(C 2H 5) 2 tetrahydrofuran solvate was obtained. The crystal structures of the p-OCH 3 derivatives of the first two series of complexes and of the ferrocenoylhydrazone derivative were determined. In the solid state, the three complexes are dimers, containing a set of seven, three and five fused rings, respectively. In every case, it was observed a symmetric anti arrangement of fused rings in relation to a central In 2O 2 four-membered ring, resulting in a configuration that resembles a chair. Cyclic voltammetric studies on the ferrocenylaroylhydrazone complexes revealed electron transference from the ferrocene group towards the indium atom, while for the salicilaldehyde–ferrocenoyl complex this was not observed.