Reduction-oxidation properties of organotransition-metal complexes. Part 21. Synthesis and X-ray structural characterisation of the redox-related pair of cyclohexadienyl complexes [Mn(CO)(dppe)(η5-C6H6Ph)] and [Mn(CO)(dppe)(η5-C6H6Ph)][PF 6]·0.5CH2Cl2

Neil G. Connelly, Mark J. Freeman, A. Guy Orpen, Alan R. Sheehan, John B. Sheridan, Dwight A. Sweigart

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The cyclohexadienyl complexes [Mn(CO)3-nLn5-C6H 6Ph)] [la, n = 1, L = PPh3; 1b, n = 2, L2 = Ph2PCH2CH2PPh2 (dppe)], prepared by U.V. photolysis of [Mn(CO)3(ηC6H6Ph)] and L, undergo reversible one-electron oxidation at a platinum electrode in CH2Cl2. The paramagnetic salt [Mn(CO) (dppe) (η-5C6H6Ph)] [PF6] (2) is isolable from the reaction between (1b) and [Fe(η-C5H5)2][PF6]. X-Ray structural studies on (1b) and (2)·0.5CH2Cl2 show the most pronounced effects of oxidation to be on the mean Mn-P distances which change from 2.221 Å in (1b) to 2.338 Å in (2). The effect on the conformation of the Mn(CO) (dppe) unit relative to the cyclohexadienyl moiety is small; in both complexes the CO ligand lies beneath the saturated ring carbon, giving approximate Cs symmetry to (1b) and (2). The structural consequences of one-electron oxidation on the geometry about the metal and within the ligands are discussed with regard to the nature of the highest occupied molecular orbital of (1b) and its depopulation in (2).

Original languageEnglish (US)
Pages (from-to)1019-1026
Number of pages8
JournalJournal of the Chemical Society, Dalton Transactions
Issue number5
Publication statusPublished - Dec 1 1985
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Chemistry(all)

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