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, [Re(2)Cl(8)](2)(-), with tertiary phosphines PEt(3) and PPr(n)(3), the influence of solvent on the reaction pathway has been studied. It has been shown that in 1-propanol at room temperature the reaction leads to a one-electron reduction of the Re(2)(6+) core. The novel dirhenium(II,III) paramagnetic products of stoichiometries [Bu(n)(4)N][Re(2)Cl(6)(PEt(3))(2)] (1a) and Re(2)Cl(5)(PPr(n)(3))(3) (2a) have been isolated and characterized. In benzene a disproportionation process occurs resulting in mononuclear rhenium(IV) complexes ReCl(4)(PR(3))(2) (PR(3) = PEt(3) (1b) and PPr(n)(3) (2b)) in addition to 1a and 2a, respectively. The solid state structures of compounds 1a, 1b, 2a.0.25C(6)H(14), and 2b have been investigated by X-ray crystallography. The crystallographic parameters are as follows: for 1a, tetragonal space group P4(2)/m with a = 11.821(2) Å, c = 14.770(3) Å, and Z = 2; for 1b, monoclinic space group P2(1)/n with a = 8.0555(4) Å, b = 12.536(2) Å, c = 10.2041(6) Å, beta = 99.167(9) degrees, and Z = 2; for 2a.0.25C(6)H(14), monoclinic space group P2(1)/n with a = 11.7679(9) Å, b = 18.574(5) Å, c = 19.688(4) Å, beta = 93.37(2) degrees, and Z = 4; for 2b, monoclinic space group P2(1)/c with a = 8.219(2) Å, b = 11.210(1) Å, c = 14.331(3) Å, beta = 93.171(9) degrees, and Z = 2. It has also been found that the disproportionation process in benzene goes by way of an intermediate complex which is an initial product of interaction between the [Re(2)Cl(8)](2)(-) and the phosphine. In the case of the triethylphosphine ligand we formulate this complex as [Bu(n)(4)N][Re(2)Cl(7)(PEt(3))(3)] (1c).
Cotton
F. Albert
FA
Laboratory for Molecular Structure and Bonding, P.O. Box 30012, Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012.
Dikarev
Evgeny V.
EV
Petrukhina
Marina A.
MA