Synthesis and characterization of mixed-metal complexes of Ag/Cu and W/Mo and a complex of Ag with heterocyclic thione ligands

Abstract

Reactions of AgI with salts of [WS(4)](2-) or [MoS(4)](2-) and with either imidazolidine-2-thione (Imt) or [1,3]diazepane-2-thione (Diap) give the complexes [WS(4)Ag(2)(Imt)(2)](n) and [MS(4)Ag(2)(Diap)(4)] [M = W or Mo]; in the case of Diap, corresponding Cu complexes can be obtained with CuCl instead of AgI. Decomposition of the Ag-Diap complexes during attempted recrystallization leads to the polymeric complex [AgI(Diap)](n). The monomeric mixed-metal Diap complexes contain edge-sharing WS(4) and AgS(4) tetrahedra, the Diap ligands being terminally bonded to Ag through sulfur. The mixed-metal W-Ag-Imt complex is a chain polymer with two different environments for the WS(4) unit and three different coordination environments for Ag, one of which is an unprecedented AgS(5) square-based pyramid; Imt ligands are terminally coordinated to Ag. [AgI(Diap)](n) has a complex polymeric chain structure with three different distorted tetrahedral environments for Ag, direct Ag-Ag bonding, both bridging and terminal I, and all Diap ligands bridging pairs of Ag atoms. All the crystal structures feature N-H[...]S or N-H[...]I hydrogen bonding. The complexes have also been characterised by infrared, UV-Vis and (1)H and (13)C NMR spectroscopy.