Reactions of the cyclic platinum(II) thiolate complex [Pt{SCH2C(O)CH2}(PPh3)2] with electrophiles, and the single-crystal structure of [{Pt[SCH2C(O)CH2](PPh3)2·HgBr2}2]

Abstract
The cyclic thiolato complex [[graphic omitted]H2}(PPh3)2]1 reacted with alkyl halides RX (MeI, EtBr or PhCH2Cl) giving the thioether complexes [[graphic omitted]H2}X(PPh3)] with the triphenylphosphine ligand trans to the thioether group. 31P-{1H} NMR spectroscopy revealed that the alkylation reactions proceed through a cationic thioether intermediate of the type [[graphic omitted]H2}(PPh3)2]+X, the rate of formation of which is highly dependent on the reactivity of the alkyl halide. Reaction of 1 with dimethyl sulfate rapidly produced an analogous intermediate which is rather stable in the presence of an excess of dimethyl sulfate as a result of the low nucleophilicity of the methyl sulfate anion. Proton NMR spectroscopy of the complexes [[graphic omitted]H2}X(PPh3)] is consistent with the presence of a rigid metallacycle in solution with the SMe group adopting an axial position. Complex 1 also forms sulfur-donor adducts with ‘soft’ metal centres such as HgII and AgI. Adduct formation is readily monitored by the influence on the 1H NMR shifts of the metallacyclic CH2 groups. A single-crystal X-ray diffraction study on the mercury(II) bromide adduct reveals the presence of a 1 : 1 dimeric complex [{[graphic omitted]H2](PPh3)2·HgBr2}2]. The complex contains bridging thiolate ligands with a BrHg(µ-Br)2HgBr unit and distorted tetrahedrally co-ordinated mercury centres.

This publication has 27 references indexed in Scilit: