Reactions of carbon disulphide with palladium(0) complexes

The reaction of PdLn (n = 3, L = PtBuPh2; n = 2, L = PtBu2Ph, PtBu3, PCy3) with CS2 in hexanes results in precipitation of either Pd(η2-CS2)L2 (L = PtBuPh2, PCy3) or Pd2(μ-CS2)2L2 (L = PtBu2Ph, PtBu3). The monomeric complexes Pd(CS2)L2 are unstable in a CS2 solution and convert to the corresponding doubly CS2-bridged dimeric complexes Pd2(CS2)2L2. It is the steric bulk of the phosphine ligands that appears to control which type of product initially precipitates. Reaction of the trinuclear clusters Pd3(CO)3L3 with CS2 gives the dimeric complexes Pd2(CS2)2L2. The molecular structure of Pd2(CS2)2(PtBu2Ph)2 has been determined by a single crystal X-ray analysis. Crystals of the complex are monoclinic, space group P21/c (a 10.373(2) b 13.684(1), c 12.173(2) Å, β 94.04(7)°) with two centrosymmetrically related dimers per unit cell. The final agreement indices (172 variables, 2071 reflections) are R = 0.032 and Rw = 0.038. The PPd(CS2)2PdP core is essentially planar with each CS2 ligand π-bonded through the CS linkage to one metal atom and σ-bonded to the other through the second S atom.