Increased Photocatalytic Activity of Post Synthetically Modified Coordination Polymer Derived from Bis-pyridyldiamide

Abstract

A one-dimensional looped chain coordination polymer (CP1) is synthesized by the reaction of CoII with N1,N3-di(pyridine-4-yl)isophthalamide. Transmetalation reaction of CP1 with CuII showed single-crystal-to-single-crystal (SC-SC) transformation to form CP2, which is also a 1D looped chain. Both CP1 and CP2 showed the presence of DMF as guest molecules near the loops of the 1D chains. CP1 and CP2 were found to have bandgap of 2.41 eV and 1.30 eV, respectively, which were calculated by Tauc plot. The difference observed in the optical bandgap of CP1 and CP2 is reflected in photocatalytic dye degradation studies. It was observed that CP2 showed much greater efficiency in degrading the dyes (Methylene blue, Methyl orange and Rhodamine B) as compared to that of CP1. The polar nature of the loops of the chains in CP1 and CP2 due to the presence of DMF was exploited to study the adsorption and desorption of I2. Adsorption of I2 in CP1 and CP2 was found to follow first order kinetics with a rate constant of 8.32 × 10–5 s–1 for CP1 and 9.71 × 10–5 s–1 for CP2. Guest inclusion reaction was performed to incorporate benzotriazole in the CP1. Impedance measurements showed a higher conductivity in the benzotriazole incorporated CP1.