Photocatalytic ability of two hetero-tetranuclear complexes with CuO2Cd cores to degrade methylene blue: Influence of their structures on activity

Two centrosymmetric hetero-tetranuclear copper(II)/cadmium(II) complexes, (mu(1,1)-N-3)(2)[(H2O)Cu(L-R)Cd(N-3)](2)center dot 2CH(3)OH (1) and (mu(1,1)-NCS)(2)[(CuLCd)-Cd-R(SCN)](2)center dot 2CH(3)OH (2), have been prepared with a compartmental reduced Schiff base ligand, H2LR = 2,2'-[(2,2-dimethyl-1,3-propanediyl)bis(minomethylene)]bis[6-methoxyphenol]. Both complexes have been characterized elemental and spectral analyses. Structures of both complexes have been confirmed by single crystal X-ray diffraction technique. Both complexes contain CuO2Cd cores. Here the bridging mode of azide and thiocyanate is quite different. Complex 1 contains mu(1,1-)azide bridges between two cadmium(II) centres whereas in complex 2, mu(-)(1,1-)thiocyanate bridges occur between copper(II) and cadmium(II) centres. The ability of both complexes to be used as photocatalyst in degrading methylene blue (MB) has been explored. The difference in photocatalytic performance may be correlated with their structures. Complex 1 shows better catalytic activity compared to complex 2, and can degrade almost 62% MB in 18 min. Comparative IR studies (before and after the photocatalytic degradation process) confirmed the stability of both catalysts. (C) 2019 Elsevier Ltd. All rights reserved.