Isolation and characterization of a blue coloured three coordinate Cu(I)-radical complex with an S donor set.

A stable three coordinate Cu(I)-radical complex with an S donor set having the general formula of [Cu(S-NHCH)(SS-NHCS)] (1) was isolated as dark blue needles. Interestingly, this complex possesses a zwitterionic ligand, S-NHCH, which is coordinated to the central Cu(I) ion its S-atom [S-NHCH C4-thiolate functionalized C2-protonated zwitterionic N-hetero cyclic carbene; SS-NHCS˙ NHC-based dithiolene radical anion]. 1 has been structurally characterized by single-crystal X-ray diffraction, and further characterized by UV-vis, IR, XPS, and EPR spectroscopy. 1 has also been studied by quantum chemical calculations.