Crystal structures of neutral trigonal bipyramidal [NiCl2(PMePh2)(PNMe2)]center dot 1/2CH(2)Cl(2) and cationic square planar [NiCl(PMePh2)(PNMe2)][PF6] complexes

The crystal structures of [NiCl2(PMePh2) . (PNMe2)] . 1/2 CH2Cl2 (1), C33H33Cl2NNiP2 . 1/2 CH2Cl2, and [NiCl(PMePh2) (PNMe2)][PF6] (2), C33H34ClF6NNiP3, have been determined by X-ray diffraction. Complex 1 crystallises in the monoclinic space group P2(1)/n, a = 11.305(6) Angstrom, b = 17.620(9) Angstrom, c = 18.061(9) Angstrom, beta = 90.48(4)degrees, V = 3597(3) Angstrom(3) and Z = 4. Refinement of 2508 observed reflections and 275 parameters converges to a conventional R of 0.051. The coordination around the Ni(II) centre is distorted trigonal bipyramidal with the two axial positions occupied by the phosphorus atom of the monodentate phosphine and the tertiary amine nitrogen of the bidentate PNMe2 chelate. The equatorial sites accommodate the remaining phosphorus of the amino-phosphine and two chlorine donors. Complex 2 crystallites in the orthorhombic space group Pbca, a = 18.61(1) Angstrom, b = 15.42(1) Angstrom, c = 23.25(2) Angstrom, V = 6673(7) Angstrom(3) and = 8. Refinement of 2351 observed reflections and 347 parameters yields R = 0.051. A square planar geometry de scribes the coordination around the metal with the two phosphorus donors located in a mutual cis-arrangement. As expected on the basis of the different coordination number, all of the metal-donor distances decrease on going from 1 to 2, as evidenced, in particular, by the Ni-N bond which contracts from 2.325(8) Angstrom to 2.056(8) Angstrom.