Triquinoxalinylene and benzoquinone based covalent organic framework as robust material for mitigation of environmental pollutants-A theoretical approach.

[Display omitted] • TQBQ-COF for detecting Industrial pollutants including NH 3 , H 2 S, HCN and PH 3. • Demonstration of nature of interactions by NCI and QTAIM analysis. • Variation in electronic properties of complexes justified by NBO, EDD and FMO analysis. • High sensitivity of TQBQ-COF for H 2 S compared to other analytes. The physisorption of pollutant gases (NH 3, HCN, H 2 S and PH 3) on TQBQ-COF has been explored using DFT calculations. The strength and nature of interactions were determined through interaction energy, non-Covalent interactions- Reduced Density Gradient (NCI-RDG) plots, Frontier Molecular Orbital (FMO), Natural bond orbital (NBO), Electron Density Difference (EDD) and Quantum Theory of Atoms In Molecule (QTAIM) analysis. The optimized geometries and interaction energy calculations revealed that the analytes interacted with Oxygen and Nitrogen atoms of TQBQ-COF leading to adsorption energy ranging from −10.66 to −5.85 kcal/mol. The values of recovery time were in agreement to that of interaction energy and decreased with the increase in temperature. The NCI-RDG plots and QTAIM analysis revealed the presence of weak van der Waals forces in all complexes and partial covalent character in H 2 S@TQBQ-COF. Charge transfer study (employing NBO and EDD analysis) depicted the transfer of charge from surface to analytes. The study of HOMO-LUMO energy gap in FMO analysis depicted the high sensitivity of TQBQ-COF for H 2 S and NH 3 compared to HCN and PH 3 due to significant lowering of HOMO-LUMO energy gap upon the adsorption of H 2 S and NH 3 on TQBQ-COF. [ABSTRACT FROM AUTHOR]