The ReH6[P(C6H5)(3)](-)(2) ion as a ligand: Complexes with M(CO)(3) fragments (M=Cr, Mo, W)

The reactions of [(H5C6)(3)P]2ReH6- with (CH3CN)(3)Cr(CO)(3), (diglyme)Mo(CO)(3) or (C3H7CN)(3)W(CO)(3) led to the formation of [(H5C6)(3)P](2)ReH(6)M(CO)(3)(-) (M = Cr, Mo, W) complexes. These have been characterized by IR and NMR spectroscopies, as well as elemental analyses. A single crystal X-ray diffraction study has also been carried out for the M = Cr complex as a K(18-crown-6)(+) salt. The complex crystallizes as a THF monosolvate in the monoclinic space group P2(1)/n with a = 22.323(6), b = 9.523(2), c = 27.502(5) Angstrom, beta = 104.98(2)degrees and V = 5648 Angstrom(3) for Z = 4. The Re-Cr separation is 2.5745(12) Angstrom, and the two phosphine ligands are oriented unsymmetrically. Although the hydride ligands were not found, the presence of three bridging hydrides and a dodecahedral coordination geometry about rhenium could be inferred. Low temperature H-1 and P-31 NMR spectroscopic studies did not reveal the low symmetry of the solid state structure.