POLYNUCLEAR HOMOMETALLIC OR HETEROMETALLIC PALLADIUM(II) PLATINUM(II) PENTAFLUOROPHENYL COMPLEXES CONTAINING BRIDGING DIPHENYLPHOSPHIDO LIGANDS .2. SYNTHESIS AND CRYSTAL-STRUCTURE OF [(C6F5)(2)PT(MU-P(C6H5)(2))(2)PD(P(C6H5)(3))]CENTER-DOT-2C(6)H(6)

The tetranuclear complexes [NBu(4)](2)[(C6F5)(2)Pt(mu-PPh(2))(2)M(mu-Cl)(2)M(mu-PPh(2))(2)Pt(C6F5)(2)] (M = Pt (A) or Pd (B)) react with PPh(3) in acetone affording [NBu(4)][(C6F5)(2)Pt(mu-PPh(2))(2)MCl(PPh(3))] (M = Pt (1), Pd(2)). However, when such reactions are carried out in CH2Cl2 or CHCl3/MeOH, the dinuclear complexes [(C6F5)(2)Pt(mu-PPh(2))(2)ML] (L = PPh(3), M = Pt (3), Pd (4); L = PPh(2)Et, M = Pd (5)) are obtained. Complexes 3 and 4 can also be obtained by reacting A and B, respectively, with O(3)ClOAgPPh(3) in CH2Cl2. The P-31 NMR indicates that 3-5 display Pt-->M donor-acceptor bonds while 1 or 2 does not show this type of metal-metal bond. The reaction of 3 or 4 with neutral or anionic monodentate ligands L' renders dinuclear derivatives [(C6F5)(2)Pt(mu-PPh(2))(2)ML'(PPh(3))](n-) n = 1: M = Pt, L' = Br (6); M = Pd, L' = CN (7). n = 0: M = Pt, L' = Py (8), CO (9); M = Pd, L' = Py (10)) in which the M center is four-coordinate and no Pt-->M bond is present. The structure of 4 has been determined by a single-crystal X-ray diffraction study. Crystals are monoclinic, space group C2/m, with a = 16.774(5) Angstrom, b = 19.404(4) Angstrom, c = 19.416(4) Angstrom, beta = 111.54(3)degrees, and Z = 4. The structure was refined to 5051 data, giving a traditional R-factor of 0.0456. The Pt-Pd distance is 2.657(1) Angstrom.