CRYSTAL-STRUCTURES OF 2 RELATED PLATINUM(II) COMPLEXES OF THE TYPE [PT(SEC(COME)=C(R)O)(PPH(3))(2)] (R=ME OR PH) FORMED BY SE-C BOND-CLEAVAGE OF ACYL-SUBSTITUTED DISELENETANES

Oxidation reactions of [Pt(PPh(3))4(]) with the two 1,3-diselenetanes, 2,2,4,4-tetraacetyl-1,3-diselenetane and 2,4-dibenzoyl-2,4-diacetyl-1 ,3-diselenetane, lead to dissection of the four-membered rings of the diselenetanes to give platinum(II) complexes containing the formally d ianionic ligands: 2,4-pentanedione-3-selenolato (2-) and 1-phenyl-1,3- butanedione-3-selenolato(2-), respectively. The crystal structures of the complexes [Pt{SeC(COMe)=C(R)O}(PPh(3))(2)] (R = Me or Ph) reveal t he five-memebered planar 2-oxa-5-selena-1-platinacyclo-3-pentene chela te ring systems with the chelating ligand bonded to platinum through t he oxygen and selenium atoms.