Preparative, X-ray, and NMR Studies of Phosphide-Bridged Palladium(I) Dimers. A New Complex with an .eta.2-Bridging PHCy2 Ligand

The preparation of several new Pd(I) cationic dinuclear complexes containing bridging PCy2 or PBu(t)2 ligands and terminal phosphine ligands is described. One of these, [Pd2(mu-PCy2)(mu-PHCy2)(PEtCy2)2]+ (7), contains a Pd-H-P bridging unit, a relatively rare type of bonding. The cationic complexes [Pd2(mu-PBut2)(PHCy2)4]+ (5) and [Pd2(mu-PBut2)(PMe3)4]+ (8) have been isolated and characterized via P-31 NMR and X-ray crystallographic studies. The structures reveal large distortions presumably of steric origin. Relevant crystallographic parameters for two complexes are as follows: for [5]BF4, C56H110BF4P5Pd2, monoclinic, space group P2(1)/c, with a = 20.929(5) angstrom, b = 15.244(5) angstrom, c = 20.860(6) angstrom, beta = 75.01(2)-degrees, V = 6429(2) angstrom 3; for [8]CF3SO3, C21H54F3O3P5Pd2S, monoclinic, space group C2/c, with a = 29.810(3) angstrom, b = 11.181(1) angstrom, c = 23.126(4) angstrom, beta = 105.99(9)-degrees, Z = 8, V = 7410(1) angstrom 3.