Syntheses and photocatalytic properties of three new d10-based coordination polymers: Effect of metal centre and ancillary ligands

Three new coordination polymers (CP) with formula [Cd(L)(bb)] (1), [Cd(L)(bbi)0.5(H2O)] (2) and [Zn2(L)2(bip)2] (3) (H2L = 3,3'-{[1,3-phenylenebis-(methyleneoxy)}dibenzoic acid; bb = 4,4'-bis(imidazolyl)biphenyl; bbi = 1'-(1,4-butanediyl)bis(imidazole) and bip = 3,5-bis(1-imidazoly)pyridine)have been synthesized hydrothermally and characterized. The single crystal X-ray diffraction analyses revealed that 1 displays a 2D structure with (3,5)-connected net topology, 2 has 2D double chain like framework, while 3 exhibits only 1D chain. An anionic organic dye methyl violet (MV) was selected as a model pollutant in aqueous media to evaluate the photocatalytic properties of the three CPs. The photocatalytic experiments revealed that these CPsexhibited good photocatalytic activities for MV degradation under UV light and also showed goodphotocatalytic stability. The difference in catalytic activity among the CPs arises due to the change in central metal ionsas well as the nature of ancillary ligands which in turn had changed the nature of framework and hence electronic properties of these CPs. The possible mechanism for the photocatalytic activity displayed by these CPs for the photodegradation of MV have been addressed using density of states (DOS) and partial DOS (pDOS) calculations.