Synthesis and Molecular Structures of Platinum and Mercury Complexes Chelated by (Phenylthiomethyl)silane Ligands

Metathesis reaction of the dithioether complex cis ‐[PtCl 2 {(PhSCH 2 ) 2 SiPh 2 }] ( 2a ) with NaBr and NaI yields the square planar complexes cis ‐[PtX 2 {(PhSCH 2 ) 2 SiPh 2 }] ( 2b , X = Br; 2c , X = I). The new compounds, which are fluxional in solution, have been studied by multinuclear NMR techniques; the crystal structures of 2a‐c have been determined by X ray diffraction. This series allows to evaluate the trans ‐influence of the halide ligands on the lengths of the Pt‐S bonds, which increase from 227.26(12) ( 2a ), 228.46(13) ( 2b ) to 229.96(15) ( 2c ) pm due to a more pronounced trans‐ influence of I compared with Br and Cl. Complexation of (PhSCH 2 ) 2 SiPh 2 ( 1a ) on HgBr 2 gives the distorted tetrahedral compound [HgBr 2 {(PhSCH 2 ) 2 SiPh 2 }] ( 3 ), having a quite loose coordination of the ligand both in solution and in the solid state [Hg‐S = 291.88(2) pm]. Alternatively, the coordination around Hg may be described as distorted square pyramidal in the solid state, since to due to a weak intermolecular Hg···Br interaction [346.72(13) pm], a dimeric motif is formed. Furthermore, the functionalised cyclic silane (PhSCH 2 ) 2 SiC 4 H 6 ( 1b ) has been prepared and co‐ordinated as chelating dithioether ligands to [PtCl 2 (PhCN) 2 ] affording the dithioether complex cis ‐[PtCl 2 {(PhSCH 2 ) 2 SiC 4 H 6 )}] ( 4 ). The crystal structure of 4 has also been determined by an X‐ray diffraction study.