Ru(III) complexes of triazole based Schiff base and azo dye ligands: An insight into the molecular structure and catalytic role in oxidative dimerization of 2-aminophenol

Abstract

Four New ruthenium(III) complexes encompassing triazole based Schiff base or azo dye ligands (HL1-HL4) have been prepared. The structural composition of the isolated compounds has been fully identified following alternative spectral and analytical methods of investigation. Among the applied tools is the measurement of the molar conductivity of the complexes solutions which demonstrated that all of them are non-electrolytes. 1:2 (M:L) stoichiometry has been concluded for all the isolated complexes with an octahedral geometrical architectures. IR spectral results of the isolated chelates assured the chelation of the ligand to the Ru center via azo or azomethine nitrogen and deprotonated hydroxyl oxygen affording the monobasic bidentate fashion of the ligands. The four synthesized complexes have been investigated for mimicking phenoxazinone synthase using o-aminophenol (OAP) as the substrate in acetonitrile/dimethyl formamide, ACN/DMF (80/20% ratio) mixed solvent by evaluating the catalytic performance of the compounds for oxidative coupling of 2-aminophenol (OAP) to 2-aminophenoxazine-3-one (APX). The obtained results showed that the complexes have TOF numbers in the range 46.92–12.12 h−1 increasing in the order Ru-(L2)2 < Ru-(L3)2 < Ru-(L4)2 < Ru-(L1)2.