作者:Mouchumi Bhuyan、Moitree Laskar、B. D. Gupta
DOI:10.1021/om7009045
日期:2008.2.1
4,4'-Disubstituted biphenyl-bridged dicobaloximes, Py(L)(2)Co-CH2-Ar-CH2-Co(L)(2)Py [L = dmgH, dpgH], have been synthesized and characterized. The cobalt-bound CH2 is diastereotopic and the dmgH (Me) shows nonequivalence in the H-1 NMR. This may occur due to atropisomerism and/or restricted rotation of the C-Ph/Co-C bond. Two X-ray structures of the biphenyl-bridged dicobaloximes, reported for the first time, show no direct or indirect interaction between the two cobaloxime units [Co(dioxime)(2)Py]. The NMR spectra and X-ray structural details complement each other. Three redox processes, Collf/coll, Co-II/Co-I, and Co-IV/Co-III, are observed in the CV study. Two cobalt centers are oxidized at different potentials as two discrete units even though these are symmetrically located with respect to each other with no interaction between them.