Fragmentation of co-ordinated carbon disulphide and dithiocarbene ligands by nucleophilic attack at carbon: the crystal structure of [(Ph3P)IPt(µ-SMe)(µ-CSMe)PtI(PPh3)]·Me2CO

Abstract

Nucleophilic attack at the carbon atom of carbon disulphide in the complex [Pt(η²-CS₂)(dppe)][dppe = 1,2-bis(diphenylphosphino)ethane] by the zero-valent platinum complex [(Pt(η²-C₂H₄)(PPh₃)₂] results in the formation of the dinuclear platinum thiocarbonyl complex [(dppe) [graphic omitted]t(PPh3)(CS)](2). A similar attack at the carbon atom of the dithiocarbene ligand in either of the complexes [PtI(PPh₃)₂{C(SMe)₂}]⁺I^–(3) or [PtI₂(PPh₃){C(SMe)₂}] yields the complex [(Ph₃P)IPt(µ-SMe)(µ-CSMe)PtI(PPh₃)]·Me₂CO, the crystal structure of which has been determined. Crystals of the complex are monoclinic, space group C2/c, with Z= 8, in a unit cell with lattice parameters a= 27.218(2), b= 11.814(2), c= 27.407(2)Å, and β= 99.636(6)°. The structure has been refined to R= 0.038 (R′= 0.035) for 3 429 unique data. The complex consists of two distorted square-planar Pt fragments which are held together by bridging –SMe and –CSMe groups. Treatment of the carbene complex (3) with dppe yields the new carbene complex [ PtI(dppe)-{C(SMe)₂}]⁺I^– which reacts similarly with [Pt(η²-C₂H₄)(PPh₃)₂] to yield [(dppe)Pt(µ-SMe)(µ-CSMe)PtI(PPh₃)]⁺I^–. This latter complex is also the product of the reaction of the thiocarbonyl complex (2) with methyl iodide. The complexes have been characterized by elemental analysis, ¹H and ³¹P-{¹H) n.m.r. and i.r. spectroscopy, and conductivity measurements.