Mixed chloride phosphine complexes of the dirhenium core. 5. Reduction or disproportionation at the Re-2(6+) unit in reactions with tertiary phosphines in different solvents

For reactions of the octachlorodirhenium anion, [Re2Cl8](2-), with tertiary phosphines PEt3 and PPr3n, the influence of solvent on the reaction pathwa y has been studied. It has been shown that in 1-propanol at room temperatur e the reaction leads to a one-electron reduction of the Re-2(6+) core. The novel dirhenium(II,III) paramagnetic products of stoichiometries [(Bu4N)-N- n] [Re2Cl6(PEt3)(2)] (1a) and Re2Cl5(PPr3n)(3) (2a) have been isolated and characterized. In benzene a disproportionation process occurs resulting in mononuclear rhenium(IV) complexes ReCl4(PR3)(2) (PR3 = PEt3 (1b) and PPr3n (2b)) in addition to 1a and 2a, respectively. The solid state structures of compounds 1a, Ib, 2a 0.25CsH14, and 2b have been investigated by X-ray cry stallography. The crystallographic parameters are as follows: for la, tetra gonal space group P4(2)/m with a = 11.821(2) Angstrom, c = 14.770(3) Angstr om, and Z = 2; for 1b, monoclinic space group P2(1)/n with a = 8.0555(4) An gstrom, b = 12.536(2) Angstrom, c = 10.2041(6) Angstrom, beta = 99.167(9)de grees, and Z = 2; for 2a . 0.25C(6)H(14), monoclinic space group P2(1)/n wi th a = 11.7679(9) Angstrom, b = 18.574(5) Angstrom, c = 19.688(4) Angstrom, beta = 93.37(2)degrees, and Z = 4; for 2b, monoclinic space group P2(1)/c with a = 8.219(2) Angstrom, b = 11.210(1) Angstrom, c = 14.331(3) Angstrom, beta = 93.171(9)degrees, and Z = 2. It has also been found that the dispro portionation process in benzene goes by way of an intermediate complex whic h is an initial product of interaction between the [Re2Cl8](2-) and the pho sphine. In the case of the triethylphosphine ligand we formulate this compl ex as [(Bu4N)-N-n] [Re2Cl7(PEt3)(3)] (1c).