INTERPLAY OF P-H AND E-H (E=S, SE) BONDS IN PALLADIUM DERIVATIVES - SYNTHESIS AND DISRUPTION OF NEW MIXED-VALENCE PALLADIUM TRIANGULO CLUSTERS MEDIATED BY PROTON MOBILITY - CRYSTAL AND MOLECULAR-STRUCTURE OF [PD3(MU-PCY2)2(MU-SPH)(PCY2H)I(SPH)]

An excess of PhEH (E = S, Se) reacts with Pd2(PCy2H)2(mu-PCy2)(mu-eta3 -C3H5) causing, by protonation of the bridging ligands, the disruption of the dinuclear unit and the formation of the monomers trans-[Pd(EPh )2(PCy2H)2]. The isolated monomers were reacted with the same pi-allyl dimer providing a synthetic route to the clusters [Pd3-(mu-PCy2)2(mu- EPh)(PCy2H)2(EPh)]; these mixed-valence triangulo complexes exhibit hi gh stability both in the solid state and in solution, but are reactive toward weak proton donors. Reaction with an excess of PhEH and PCy2H rapidly and quantitatively gives the monomers trans-[Pd(EPh)2(PCy2H)2] . All complexes were characterized by multinuclear NMR analyses. [Pd3( mu-PCy2)2 (mu-SPh)(PCy2H)2(SPh)] crystallizes in the Pnma space group (orthorhombic, Z = 4) with the following unit cell dimensions: a = 13. 587(4), b = 25.231(8), c = 18.306(6) angstrom.