Aqueous Route to Stable Luminescent Tetranuclear Copper(I) Dithiophosphonate Clusters.

A series of seven luminescent copper(I) dithiophosphonate (dtp) clusters of the type Cu4L4 (L = S2PR(OR')-) were formed from CuCl2·2H2O precursor in aqueous medium under ambient conditions. The dtp ligand serves the dual function of acting as a sacrificial reducing agent and cluster core stabilizer. The new clusters were characterized by 1H and 31P NMR and ESI-MS, and the single-crystal X-ray structures for two representative clusters [Cu4{(S2P(1,4-C6H4OMe)(OR')}4] (R' = OCH(CH3)2; CH2C6H5) were determined. The redox reaction yielded clusters in satisfactory yield, and all exhibited luminescence with λemmax in the range 519-534 nm and half-lives in the range 10-14 μs.