Syntheses, displacement behavior, hetero-atom carbene, and crystal structures of platinum complexes containing the N,N-dimethylthiocarbamoyl, Me2NCS, ligand: Structures of [Pt(PPh3)(Cl)]2(μ,η2-SCNMe2)2, [Pt(PPh3)(η2-dppa){η1-C(S)NMe2}][Cl], and [Pt(PPh3)2

In solution state, the complex [Pt(PPh3)2(η1-SCNMe2)(Cl)] (1) shows intermolecular displacement of two triphenylphosphine ligands to form the bridging η2-thiocarbamoyl diplatinum complex [Pt(PPh3)Cl]2(μ,η2-SCNMe2)2 (2). Intramolecular displacement of the chloride product η2-thiocarbamoyl complex [Pt(PPh3)2(η2-SCNMe2)][Cl] (3) was not been detected from the 31P{1H} NMR experiments. However, the chelating η2-thiocarbamoyl complex [Pt(PPh3)2(η2-SCNMe2)][PF6] (4) can be produced by the reaction of 1 with NH4PF6 in acetone at ambient temperature. Treatment of 1 with dppa {bis(diphenylphosphino)amine} in dichloromethane at room temperature results in the formation of the complex [Pt(PPh3)(η2-dppa){η1-C(S)NMe2}][Cl] (5). Treatment of 4 with EtOCS2K or MeOCS2K yields Fischer-type carbene-complex [Pt(PPh3){η1-C(SEt)(NMe2)}(η2-S2CO)] (7) or [Pt(PPh3){η1-C(SMe)(NMe2)}(η2-S2CO)] (8). The carbene-complexes 7 and 8 are formed via alkyl migration of the alkyldithiocarbonate ligand to the thiocarbamoyl ligand. Complex 1 reacts with EtOCS2K, resulting in the formation of the η2-dithiocarbonate complex [Pt(PPh3)(η1-SCNMe2)(η2-S2COEt)] (6) and the carbene-complex[Pt(PPh3){η1-C(SEt)(NMe2)}(η2-S2CO)] (7) with a ratio of 3:2 according to the integration of the 31P{1H} NMR spectra. By continuously stirring mixtures 6 and 7 in the CH2Cl2 solution for 4 h, complex 7 was formed as the final product. All of the complexes were identified by spectroscopic methods and complexes 2, 5, and 7 were determined by single-crystal X-ray diffraction.

Complex [Pt(PPh3)2(η1-SCNMe2)(Cl)] (1) shows the intermolecular displacement of the triphenylphosphine ligands to form the bridging η2-thiocarbamoyl diplatinum complex [Pt(PPh3)Cl]2(μ,η2-SCNMe2)2 (2). The reaction of 1 with EtOCS2K or MeOCS2K forms carbene-complex [Pt(PPh3){η1-C(SEt)(NMe2)}(η2-S2CO)] (7) or [Pt(PPh3){η1-C(SMe)(NMe2)}(η2-S2CO)] (8) via alkyl migration of the alkyldithiocarbonate ligand to the thiocarbamoyl ligand.Figure optionsDownload as PowerPoint slide