Syntheses, characterization of Ni(II)/Zn(II) complexes derived from flexible tricarboxylate ligand and 2,2′-bipyridine and their methyl violet dye photodegradation applications

Abstract

Three new complexes comprising Ni(II) and Zn(II) metal centers having compositions [Zn2(HL)2(bpy)2(H2O)2] (1), [Ni(H2L)(bpy)(H2O)2(OH)] (2) and [Ni(H2L)2(bpy)2] (3) have been synthesized by adopting mixed ligand strategy using 4′-(3,4- dicarboxylphenyloxy) -4-biphenylcarboxylic acid (H3L) as main ligand and 2,2′-bipyridine (bpy) as co-ligand. These complexes have been characterized by microanalyses, FTIR and single crystal X-ray diffraction technique. The single crystal X-ray analyses reveal that all the three complexes have 2D supramolecular network constructed by hydrogen bonding interactions. These complexes have been employed as photocatalysts for the photodegradation of methyl violet (MV) dye. The photocatalytic experiments reveal that amongst all three complexes, the complex 2 exhibits best photocatalytic performance and degrades 92.8% of MV in time span of 100 min. The plausible photocatalytic degradation mechanism have been proposed with the help of trapping experiments and density of states calculations.