Mixed chloride/phosphine complexes of the dirhenium core. 10. Redox reactions of an edge-sharing dirhenium(III) non-metal-metal-bonded complex, Re(2)(mu-Cl)(2)Cl(4)(PMe(3))(4).
Reduction and oxidation reactions of the dirhenium(III) non-metal-metal-bonded edge-sharing complex, Re(2)(mu-Cl)(2)Cl(4)(PMe(3))(4) (1), have been studied. Several new mono- and dinuclear rhenium compounds have been isolated and structurally characterized in the course of this study. Reductions of 1 with 1 and 2 equiv of KC(8) result in an unusual face-sharing complex having an Re(2)(5+) core, Re(2)(mu-Cl)(3)Cl(2)(PMe(3))(4) (2), and a triply bonded Re(II) compound, 1,2,7,8-Re(2)Cl(4)(PMe(3))(4) (3), respectively. Two-electron reduction of 1 in the presence of tetrabutylammonium chloride affords a new triply bonded complex of the Re(2)(4+) core, [Bu(n)()(4)N][1,2,7-Re(2)Cl(5)(PMe(3))(3)] (4). Oxidation of 1 with NOBF(4) yields a Re(IV) mononuclear compound, trans-ReCl(4)(PMe(3))(2) (5). Two isomers of the monomeric Re(III) anion, [ReCl(4)(PMe(3))(2)](-) (6, 7), have been isolated as side products. The crystal structures of compounds 2 and 4-7 have been determined by X-ray crystallography. The Re-Re distance in the face-sharing complex 2 of 2.686(1) A is relatively short. The metal-metal bond length in anion 4 of 2.2354(7) A is consistent with the usual values for the triply bonded Re(2)(4+) core compounds. In addition, a cis arrangement of trimethylphosphine ligands in the starting material 1 is retained upon reduction in the dinuclear products 2-4.
Cotton
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Laboratory for Molecular Structure and Bonding, P.O. Box 30012, Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, USA.
Dikarev
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Petrukhina
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