SYNTHESIS AND CARBONYLATION REACTIONS OF ALKYL AND PHENYL COMPLEXES OF PALLADIUM-(11) AND PLATINUM-(II) CONTAINING BETA-DIKETONATE TYPE LIGANDS

Methyl and phenyl complexes of the formula [MR(beta-dik)(PPh3)] (M = Pt or Pd, R = Me or Ph, beta-dik = beta-diketonate or monothio-beta-diketonate ligand) have been prepared and fully characterized. Carbon monoxide readily inserts into the M-C bond to form the corresponding acyl complexes, and several of these complexes were isolated and characterized. Kinetic studies on the carbonylation of the palladium(II) complexes suggests that it is a pseudo-first order reaction with a rate that is sensitive to the nature of the beta-diketonate ligand. Factors which influence the insertion process including the important role of the beta-diketonate ligand in controlling the insertion step are discussed. The crystal structure of [Pt(COMe) (bzac) (PPh3)] (bzac = 3-mercapto-1 -phenylbut-2-en-1-onate) has been determined (R = 0.040 for 6198 observed reflections). Crystals are monoclinic, space group P2(1)/c, a = 14.785(3), b = 10.654(8), c = 20.102(8) angstrom, beta = 1 22.56(2)-degrees and Z = 4. The complex has square planar co-ordination with the acyl group trans to the oxygen atom [Pt-S, -P, -O, -C 2.291(2), 2.267(2), 2.134(5), 1.974(9) angstrom]. The chelate ring forms an angle of 3.6(1)-degrees with the PtSOPC co-ordination plane.