4,5-Bis(methylthio)-1,3-dithiole-2-thione, a versatile sulphur-rich building block for the self-assembly of Cu(I) and Ag(I) coordination polymers: Dithioether versus thiocarbonyl bonding

Reported herein is the investigation of the coordination chemistry of the ligand 4,5-bis(methylthio)-1,3-dithiole-2-thione (L) towards several Ag(I) salts (AgNO3, AgClO4, AgCF3SO3 and Ag-p-MeC6H4SO3) and Cu(I) (CuBr and [Cu(MeCN)4](PF6)). Six polymeric complexes have been characterised by single-crystal X-ray diffraction, FT-IR spectra and elemental analysis. This work evidences five different coordination modes for L. The sulphur-rich ligand always coordinates via the thiocarbonyl group. Additional metal–thioether interactions give rise in some cases to a polymeric structure such as in the molecular wire-like 1D polymer {[Cu(μ2-L)(MeCN)](PF6)}n. Supramolecular structures arise from a combination of metal···ligand and short S···S Van der Waals interactions. Furthermore, the emission spectra of the strongly luminescent 2D coordination polymer [Ag(μ2-L){μ2-(p-CH3C6H4SO3)}]n have been recorded.

The self-assembly of supramolecular networks has been achieved by reaction of the ligand 4,5-bis(methylthio)-1,3-dithiole-2-thione (L) with several Ag(I) and Cu(I) salts. Five different coordination modes have been identified for this sulphur-rich ligand by X-ray crystallography. The luminescent properties of these materials have been investigated.Figure optionsDownload as PowerPoint slideHighlights
► Six transition metal coordination polymers have been structurally characterised using a sulphur-rich ligand.
► Five coordination modes have been identified for the ligand.
► The ligand coordinates preferentially via the thiocarbonyl group rather than a chelating mode involving the thioether groups.
► Silver coordination polymers are strongly luminescent.