Solvothermal in situ formation of a hexanuclear copper(I) complex with 2-thiolate-N,N′-dimethylnicotinamide

Solvothermal reaction of 2-mercaptonicotinic acid (HL1) with copper(II) nitrate in DMF/methanol medium leads to the production of a novel hexanuclear complex [Cu(L2)]6 · (H2O)2 (1), in which in situ formation of an anionic ligand 2-thiolate-N,N′-dimethylnicotinamide (L2) and reduction of copper(II) to copper(I) are observed. X-ray single-crystal structure of 1 reveals that each copper(I) center adopts a trigonal geometry provided by two thiolate and one pyridyl groups from three separated L2 ligands. As a result, six copper(I) ions are interconnected by six μ3–L2 bridges to afford a hexanuclear cluster, in which the octahedral Cu6 core is stabilized by significant cuprophilic interactions.