Coinage metal complexes of selenoureas derived from N-heterocyclic carbenes

We describe the synthesis and characterisation of a series of new copper and silver complexes with selenourea ligands derived from common and readily-prepared N-heterocyclic carbenes (NHCs). The copper complexes behave somewhat predictably, typically leading to [CuCl(L)] complexes (with two exceptions). The silver complexes display a diverse range of structural motifs, including [AgCl(µ-L)]2, [AgCl(L)2], [Ag(L)2]+, [Ag(L)3]+, and [(Ag(L)2)2(µ-L)]2+ species. All new complexes are characterised by multinuclear NMR spectroscopy, and several examples are characterised by X-ray crystallography. This study demonstrates the diversity of coordination behaviour that these selenourea ligands can engage in.