Rare or unprecedented isomers of (Re2Cl6(PR3)2) stoichiometry

The isolation of various new paramagnetic dirhenium(II,III) anions of the formula (Re2Cl6P2)- (P2 = (PPr(super n)3)2, (PEt2Ph)2, dppp)) was conducted in the form of their tetrabutylammonium salts as the kinetic products in the reactions of (Re2Cl8)2- with an appropriate phosphine ligand. Characterization of all three complexes was done in solution by cyclic vovltammetry, electron spin resonance and mass spectrometry.Results show that a compound of the (Re2Cl6(PR3)2 stoichiometry can crystallize not only as the well-known centrosymmetric C(sub 2h) isomer, but also as the noncentrosymmetric C2 isomer.