Electrochemical Investigations of Isomerism in Manganese and Group (VI) Dicarbonylbis [1,2-bis(diphenylphosphino)ethane] Complexes

F. L. Wimmer, M. R. Snow, A. M. Bond

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Abstract

A series of complexes of the general formula [M(CO)2(DPE)2]0,+,2+ is known (M = Mn, Cr, Mo, W; DPE = 1,2-bis(diphenylphosphino) ethane). In addition to existing in several oxidation states, some of the complexes have been isolated in cis and trans isomeric forms. Electrochemical investigations at mercury and platinum electrodes in acetone, dichloromethane, and nitromethane have given a wide variety of new synthetic, kinetic, and thermodynamic data on the complexes. The electrochemistry of the different oxidation states and isomeric forms is remarkably different and a highly specific technique for studying these complexes has been obtained. Strong evidence for the existence of the new complexes cis-[Cr(CO)2(DPE)2], trans-[Cr(CO)2(DPE)2]2+, trans-Mo(CO)2(DPE)2, and trans-W(CO)2(DPE)2 and other complexes is presented. Evidence for the existence of cis-[M(CO)2(DPE)2]+ (M = Cr, Mo, W) isomers in forms that are readily isomerized to the trans isomer has also been obtained. These complexes are stabilized considerably at low temperature. All thermodynamic data obtained are in accord with the known chemistry of the compounds. In oxidation state II, there is no evidence for stable cis isomers, while six-coordinate trans species decrease in kinetic stability in the order Cr > (Mo≃ W).

Original languageEnglish
Pages (from-to)1617-1623
Number of pages7
JournalInorganic Chemistry
Volume13
Issue number7
DOIs
Publication statusPublished - 1 Jul 1974
Externally publishedYes

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