Syntheses and reactivity of pentachlorophenylpalladium(I) derivatives. Molecular structure of Pd₂(μ-dppm)₂(C₆Cl₅)₂

The syntheses of [XPd(μ-dppm)₂Pd(C₆Cl₅)](X = Cl, C₆Cl₅ are described. Other neutral halogeno-pseudohalogeno-palladium(I) complexes [XPd(μ-dppm)₂Pd(C₆Cl₅)] (X = Br, I, SCN or CNO) have been obtained from [ClPd(μ-dppm)₂Pd(C₆Cl₅)] by metathetical reactions, and SnCl₂ inserts into the PdCl bond to give the Pd-SnCl₃ compound. The cationic derivatives [LPd(μ-dppm)₂Pd(C₆Cl₅)]BPh₄ (L = PPh₃, P(OPh)₃, AsPh₃, SbPh₃, tht) have also been prepared. SO₂ or RN₂⁺ insert into the PdPd bond of [ClPd(μ-dppm)₂Pd(C₆Cl₅)] to give A-frame Pd^II complexes, but do not react with (C₆Cl₅)Pd(μ-dppm)₂Pd(C₆)Cl₅. The nature of the products of the reactions of XPd(μ-dppm)₂Pd(C₆Cl₅) with RNC (R = t-Bu, Cy, p-Tol, CNC₆H₄NC) depend on the isonitrile used and the reaction conditions. The molecular structure of (C₆Cl₅)Pd(μ-dppm)₂Pd(C₆Cl₅) has been established by a single crystal X-ray study. The crystals are triclinic, space group P1, with 2 molecules of the 2 CH₂ClCH₂Cl solvate in a cell of dimensions a 12.986(4), b 13.213(5), c 21.254(6) Å, α 90.49(3), β 89.204(25), γ 102,86(3)°, V 3554.8 ų. Of 9156 data collected on a four-circle diffractometer, 4474 observed reflections were used in the refinement (R = 0.0902). The complex has no crystallographically imposed symmetry, but overall is close to D_2d. The PdPd bond length is 2.6704(21) Å.