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

Abstract

Three new coordination polymers (CPs) 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-imidazolyl)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 a 2D double chain-like framework, while 3 exhibits only 1D chains. 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 CPs exhibited good photocatalytic activities for MV degradation under UV light and also showed good photocatalytic stability. The difference in catalytic activity among the CPs arises due to the change in the central metal ions as well as the nature of the ancillary ligands, which in turn changed the nature of the framework and hence the electronic properties of these CPs. The possible mechanisms for the photocatalytic activity displayed by these CPs for the photodegradation of MV have been addressed using the density of states (DOS) and partial DOS (pDOS) calculations.