A copper(II) thiolate from reductive cleavage of an S-nitrosothiol.

S-Nitrosothiols RSNO represent circulating reservoirs of nitric oxide activity in the plasma and play intricate roles in protein function control in health and disease. While nitric oxide has been shown to reductively nitrosylate copper(II) centers to form copper(I) complexes and ENO species (E = R2N, RO), well-characterized examples of the reverse reaction are rare. Employing the copper(I) β-diketiminate [Me2NN]Cu, we illustrate a clear example in which an RS–NO bond is cleaved to release NOgas with formation of a discrete copper(II) thiolate. The addition of Ph3CSNO to [Me2NN]Cu generates the three-coordinate copper(II) thiolate [Me2NN]CuSCPh3, which is unstable toward free NO.