Synthesis, structures and photophysical properties of polynuclear copper(I) iodide complexes containing phosphine and 4,4 '-bipyridine ligands

摘要

The highly luminescent polynuclear Cu(I) iodide complexes, [(Cu(2)I(2))(4,4'-bipy)(PCy(3))(2)](2) center dot 4H(2)O (1), [(Cu(2)I(2))(4,4'-bipy)(PCy(3))(2)](infinity) (2), [(Cu(2)I(2))(4,4'-bipy)(dcpm)](infinity) (3) and [(Cu(2)I(2))(4,4'-bipy)(dppm)](infinity) (4), were prepared by reacting CuI with tricyclohexylphosphine (PCy(3)), bis(dicyclohexylphosphino)methane (dcpm) or bis(diphenylphosphino)methane (dppm) and 4,4'-bipyridine (4,4'-bipy), and their structures were determined by X-ray crystal analysis. The reported complexes [CuClPCy(3)](2) (5) and [CuIPCy(3)](2) (6) were also prepared for comparison. In solid state, complexes 1-6 display intense long-lived phosphorescence with lambda(max) at 605, 565, 640, 570, 430 and 450 nm at room temperature, and the solid-state emission quantum yields are 0.11, 0.20, 0.29, 0.35, 0.67 and 0.83, respectively. The relatively high-energy emissions of 5 and 6 are attributed to arising from metal-centered MC (3d --> 4s, 4p) excited state, while the low-energy emissions of 1-4 are assigned to a metal-to-ligand charge transfer (d --> pi(.) MLCT) excited state.