Exploring the photocatalytic activity of synthesized hydrogen bonded charge transfer co-crystal of chloranilic acid with 2-ethylimidazole: DFT, molecular docking and spectrophotometric studies in different solvents

Abstract

An organic donor (2-ethylimidazole) and an organic acceptor (chloranilic acid) were used to investigate the charge transfer (CT) interaction in polar solvents. Initially, interaction occurs between the electron-rich donor and electron-deficient acceptor through the H-bonding [N+−H····O−], which ultimately results in the formation of CT complex. The CT complex was analyzed using elemental analysis, FTIR, SC-XRD, NMR, UV, and SEM. Based on the results obtained, we concluded that a weaker H-bond is responsible for CT complex formation. The molecular docking study revealed that the CT complex binds precisely and effectively to human serum protein with a free energy value of −8.2 kcal/mol−1. We have further demonstrated the utility of the synthesized complex as an efficient photo-catalyst to degrade methylene blue (MB) and 93% photo-degradation was achieved under UV irradiation for 120 min. Furthermore, the scavenging experiment was performed to determine the mechanism of photo-degradation, which showed the formation of h+ and O2−•as primary active species. DFT calculations using the B3LYP/6-311G++ level of theory were employed.