A new paddle wheel type Cu(II) complex with photoluminescence and photocatalytic properties

Abstract

A paddle wheel-shaped complex formulated [Cu2(piv)4(CH3OH)2]·1.5(CH3OH)·0.5(H2O) (1) has been synthesized by a reaction of Cu(NO3)2·3H2O with pivalic acid. The structure of the complex is characterized by FTIR, elemental analysis and single X-ray crystallography. The crystal structure demonstrates that complex exhibits a paddle wheel type configuration. The asymmetric unit of 1 is composed of a half molecule due to the existence of an inversion center between the two Cu(II) centers. The oxygen atoms of the pivalate serve as bridging ligands, and the two methanol molecules occupy the axial position. Each pivalate ion has syn-, syn- coordination mode and its geometry may be described as square pyramidal. The complex works well as a photocatalyst, breaking down methylene blue (MB) by 78.26% after 120 minutes of 30 W ultraviolet light exposure. The optimized photocatalytic parameters were as follows; catalyst loading = 40 mg, primary concentration of MB = 15 mg/L, temperature = 323K, and pH = 8. The reaction kinetics were best demonstrated by a pseudo-first-order kinetic model followed by a rate constant of 0.00715 min–1. The reuse of the catalyst over five photocatalytic runs suggested its excellent sustainability and recyclability. Hydroxyl radicals and superoxide anions were found to be active participants in the catalytic reaction, as investigated by scavenging studies. These findings contributed to a deeper understanding of the mechanistic aspects of the photocatalytic reaction. Theoretical investigation is well support to experimental work.