Electronic properties, redox behavior, and interactions with H2O2 of pH-sensitive hydroxyphenyl-1,2,4-triazole-based oxovanadium(V)complexes

Browne, W.R., Ligtenbarg, A.G.J., de Boer, J.W., van den Berg, T.A., Lutz, M., Spek, A.L., Hartl, F. ORCID: https://orcid.org/0000-0002-7013-5360, Hage, R. and Feringa, B.L. (2006) Electronic properties, redox behavior, and interactions with H2O2 of pH-sensitive hydroxyphenyl-1,2,4-triazole-based oxovanadium(V)complexes. Inorganic Chemistry, 45 (7). pp. 2903-2916. ISSN 0020-1669 doi: 10.1021/ic051848x

Abstract/Summary

The syntheses and spectroscopic characterization of two 1,2,4-triazole-based oxovanadium(V) complexes are reported: 1(-)[VO(2)L1](-) and 2 [(VOL2)(2)(OMe)(2)] (where H(2)L1 = 3-(2'-hydroxyphenyl)-5-(pyridin-2"-yl)-H-1-1,2,4-triazole, H3L2 = bis-3,5-(2'-hydroxyphenyl)-1H-1,2,4-triazole). The ligand environment (N,N,O vs O,N,O) is found to have a profound influence on the properties and reactivity of the complexes formed. The presence of the triazolato ligand allows for pH tuning of the spectroscopic and electrochemical properties, as well as the interaction and stability of the complexes in the presence of hydrogen peroxide. The vanadium(IV) oxidation states were generated electrochemically and characterized by UV-vis and EPR spectroscopies, For 2, under acidic conditions, rapid exchange of the methoxide ligands with solvent [in particular, in the vanadium(IV) redox state] was observed.