Mono- and tetranuclear copper(I) complexes with N-heterocyclic chelating and triphenylphosphine ligands: Crystal structures, luminescent and heterogeneous catalytic properties

N-heterocyclic chelating and triphenylphosphine ligands react with cuprous halide to form a variety of copper(I) complexes, namely, mononuclear [Cu(PBO)(PPh3)Br](CH2Cl2)-C-. (1) and [Cu(PBM)(PPh3)I] (2) (PBO=2-(2-Pyridyl)benzoxazole, PBM=2-(2-Pyridyl)benzimidazole, PPh3=triphenylphosphine) and tetranuclear [Cu-4((2)-I)(2)((3)-I)(2)(PPh3)(4)](.)2CH(2)Cl(2) (3) have been synthesized and characterized. Complexes 1 and 2 are basically alike; both of them are mononuclear and four-coordinated, possessing a slightly distorted trigonal pyramidal geometry. Complex 3 is tetranuclear and the coordination numbers of the two copper(I) atoms are three and four, Cu(1) forming an approximate trigonal planar coordination environment, while Cu(2) is a slightly distorted trigonal pyramidal geometry, resulting in a distorted chair-like conformation. Complexes 1 and 2 are emissive in the solid state at ambient temperature, with the maxima at 552 and 602nm, respectively, due to a MLCT excited state. Moreover, complex 3 manifests promising heterogeneous catalytic activities for the degradation of methylene blue (MB), with degradation efficiency of 99% under ambient light.