A novel luminescent ionic trinuclear Cu3I2 cluster cuprous complex supported by a P^N ligand: synthesis, structure characterization, properties and TD-DFT calculations.

Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title ionic trinuclear Cu3I2 complex, tris[μ2-diphenyl(pyridin-2-yl)phosphane-κ2P:N]di-μ3-iodido-tricopper(I)(3 Cu-Cu) hexafluoridophosphate, [Cu3I2(C39H32NP)3]PF6, conventionally abbreviated as [Cu3I2(Ph2PPy)3]PF6, is described. Each CuI atom is coordinated by two μ3-iodide ligands and by a P and an N atom from two Ph2PPy ligands, giving rise to a CuI2PN tetrahedral coordination geometry about each CuI centre. The electronic absorption and photoluminescence properties of this trinuclear cluster have been studied on as-synthesized samples, which had been examined previously by powder X-ray diffraction. A detailed time-dependent density functional theory (TD-DFT) study was carried out and showed a green emission derived from a halide-to-ligand charge transfer and metal-to-ligand charge transfer 3(X+M)LCT excited state.