Synthesis, characterization, CV, and X-ray structures of aryl cobaloximes

Aryl cobaloximes, ArCo(dioxime)(2)Py (1-9) (Ar = phenyl, 1-naphthyl, 2-naphthyl; dioxime = dmgH, dpgH, gH) have been synthesized and characterized primarily by NMR and elemental analyses and molecular structures of four complexes have also been determined crystallographically. The electronic and steric effects of the aryl ring size and the equatorial dioxime affect the NMR chemical shifts and the X-ray structural parameters. The cyclic voltammetry study shows that the aryl cobaloximes are reduced electrochemically more easily as compared to the corresponding alkyl complexes. These complexes have a robust Co-C bond and are very stable in solution and show no sign of decomposition even on irradiation under oxygen atmosphere - an unusual property of any organocobaloxime. (C) 2010 Elsevier B. V. All rights reserved.