Copper dithiolene [Cu(SC6H2Cl2S)2]− units connected to alkaline/copper complexes: from ionic assemblies to discrete molecular entities and coordination polymers

Abstract

Direct reaction between Cu(ClO₄)₂ and 3,6-dichloro-1,2-benzenedithiol (HSC₆H₂Cl₂SH) in the presence of basic salts, i.e. NaOH, KOH, Rb₂CO₃ or Cs₂CO₃, leads to a series of bis(dithiolato)cuprate(III) [Cu(SC₆H₂Cl₂S)₂]⁻ coordination complexes and coordination polymers depending upon the metal counterion used in the process. These compounds clearly show the robustness of the bis(dithiolato)cuprate(III) [Cu(SC₆H₂Cl₂S)₂]⁻ entities, showing a nearly planar structure which is retained not only when they interact weakly with alkaline cations but also when they do it with more strongly interacting copper(I) ions. In the latter case, the interaction provides one of the few examples so-far reported on Cu^I/Cu^III mixed oxidation state compounds. This study also shows that the sulfur and chloro donor atoms of the [Cu(SC₆H₂Cl₂S)₂]⁻ entity are able to anchor soft-metal cations giving rise to the formation of coordination polymers. A semiconductor behaviour is observed in the polymers {[Rb(OH₂)][Cu(SC₆H₂Cl₂S)₂]}_n and {[Cs(OH₂)][Cu(SC₆H₂Cl₂S)₂]}_n.