SYNTHESIS AND REACTIONS OF CATIONIC PALLADIUM AND PLATINUM CYCLOPENTADIENYL COMPLEXES - MOLECULAR-STRUCTURE OF BIS-(DIPHENYLPHOSPHINO)ETHANE]PLATINUM(II)TRIFLATE

The palladium and platinum triflate complexes [M(OTf)2(P-P)] (P-P = dp pm, dppe, dppp) react with cyclopentadienylthallium to produce the ion ic, eta5-cyclopentadienyl complexes [M(eta5-C5H5)(P-P)]OTf, which are isolated as air-stable solids. They have been characterized by NMR spe ctroscopy, elemental analysis, and, in the case of [Pt(eta5-C5H5)(dppe )]OTf, X-ray crystallography. The compound crystallizes in the monocli nic space group P2(1) with a = 9.822(3) angstrom, b = 12.072(4) angstr om, c = 13.702(5) angstrom, beta = 110.56(2)degrees, V = 1521.2(9) ang strom3, and Z = 2. Least-squares refinement converged at R = 0.0390 an d R(w) = 0.0516 based on 3819 reflections with F > 4.0sigma(F). In CDC l3 solution [Pd(eta5-C5H5)(dppe)]+ reacts with PEt3 to give [PdCl(PEt3 )(dppe)]+, but in d6-acetone displacement of dppe occurs to produce [P d(eta5-C5H5)(PEt3)2]+. The reaction of the dppm compound with PEt3 giv es many products, whereas the reaction of [Pd(eta5-C5H5)(dppp)]+ is ve ry slow. The reactions of [Pt(eta5-C5H5)(P-P)]+ (P-P = dppm, dppp) wit h PEt3 are also very slow, but with the dppe complex two isomeric prod ucts are obtained. These are identified from their NMR spectra as the two possible sp2-bonded, eta1-cyclopentadienyl complexes [Pt(C5H5)-(PE t3)(dppe)]+.