Synthesis and Characterization of Dinuclear Palladium Complexes with Bridging Selenide or Selenoxide Ligands, Including X-ray Characterization of anti-Pd2Cl2(μ-Se)(μ-dpmMe)2 [dpmMe = 1,1-Bis(diphenylphosphino)ethane]

Article abstract of DOI:10.1021/ic00128a024

The complexes Pd2Cl2(P-P)2, where (P-P) = μ-bis(diphenylphosphino)methane, dpm, or μ-1,1-bis(diphenylphosphino)ethane, dpmMe, react with elemental selenium to give the A-frame adducts Pd2Cl2(μ-Se)(P-P)2, which can be oxidized by t-BuOOH to the μ-SeO derivatives. Reaction of H2Se with Pd2Cl2(dpm)2 generates Pd2Cl2-n(SeH)n(μ-Se)(dpm)2 species (n = 0-2). anti-Pd2Cl2(μ-Se)(dpmMe)2 (2d) crystallizes in the monoclinic space group P21/c with a = 11.986(2) ?, b = 24.141(2) ?, c = 18.921(2) ?, β = 106.64(1)°, V = 5243.2(11) ?**3, and Z = 4; the structure was refined against F**2 to wR2 = 0.1338 (R1 = 0.0476) for 9838 reflections with I > 2σ(I). 2d is the first structurally characterized A-frame complex with anti disposition of substituents at the methylene C atoms of the diphosphine ligands. A correlation between the (77)Se NMR shift measured for Pd2Cl2(μ-Se)(P-P)2 and the equilibrium constant for the reversible binding of CO by the Pd2Cl2(P-P)2 species reflects factors affecting binding at the apical site.