A Polynuclear d¹⁰−d¹⁰ Metal Complex with Unusual Near-Infrared Luminescence and High Thermal Stability

Three d10−d10 transition-metal complexes with organosulfur ligands, Cu6(btt)6 (1), Cu4(btt)4 (2), and Ag6(bmt)6·6THF (3) (Hbtt = 2-benzothiazolethiol, Hbmt = 2-benzimidazolethiol, and THF = tetrahydrofuran), were synthesized and characterized. Complexes 1 and 2 with similar coordination environments are isomers crystallized from the same solvothermal reactions, but they cause great differences in both the structures and luminescent behaviors. The hexanuclear cluster 1 exhibits unusual near-infrared luminescence and high thermal stability, while complex 2 with tetranuclear cores and stronger metal−metal bonds shows an intense red emission like that from complex 3.