Crystal Structure, Spectroscopy and Photocatalytic Properties of a Co(II) Complex Based on 5-(1,2,4-triazol-1-yl)pyridine-3-carboxylic Acid

Abstract

A novel cobalt(II) complex, namely [Co(tpa)2(H2O)4]·2H2O (1) (Htpa = 5-(1,2,4-triazol-1-yl)pyridine-3-carboxylic acid) has been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 was further characterized by elemental analysis, FTIR spectrum, electronic spectrum, X-ray powder diffraction and thermal gravimetric analysis. Structural analysis shows that complex 1 was stabilized via π···π stacking and hydrogen bonding interactions to give a 3D supramolecular framework. Hirshfeld surface analysis showed that O···H (29.5%), H···H (23.8%), N···H (21.5%) and π···π (8.6%) intermolecular contacts are the most important interactions in the crystal of 1. In addition, the synthesized Co(II) complex showed favorable photocatalytic activity for the degradation of methyl orange (MO) under UV light at room temperature. The degradation process of MO was in accordance with the first-order reaction kinetics, and the t1/2 for the reaction is 27.3 min, and the apparent rate constant is k = 2.54 × 10−2 min−1.