| Abstrakt: |
The structures and properties of Circumtrindene derivatives were studied at the M062X/6-31 + G(d,p) and M062X/LANL2DZ levels of theory in the gas phase and water as a solvent. Novel derivatives of Circumtrindene were designed by providing XH (X = NH, O, S) groups on the peripheral five-membered rings. Concave isomers were more stable (14.99–21.25 kcal/mol) than convex isomers. In these compounds, NH, OH, and SH groups were attached directly to the bowl and did not represent the proper size and flexibility to catch and hold ionic contaminants. Therefore, they could not be considered suitable for removing anions and cations. In the next series, the arms were extended to CH2XH (X = NH, O, S). In these flexibility derivatives, the average distances of heteroatoms were sufficient (0.99–1.26 Å) in removing anionic (Cl− and S2-) and cationic (Hg2+) contaminants. A comparison of removal equilibrium constants showed that the amine-containing derivative (X = NH) (K = 43192, 99.52% removal) was more effective than the alcoholic derivative (X = O) (K = 10, 73.49% removal) in removing Cl−. The alcohol derivative (X = OH) was more effective in removing S2− (K = 218530, 99.79% removal). On the other hand, the amine derivative (X = NH) possessed smaller energy barriers (ΔG#) of 7.44 and 8.91 kcal/mol for Cl− and S2− uptake, respectively compared to the corresponding alcohol derivative. The thiol derivative (X = S) was effective in trapping Hg2+ (K = 1.35 × 107), achieving a removal rate of 99.97%. Calculations in a PCM solvent (water) showed a decrease in Gibbs free energy barriers for ion removal, with values of 0.69 and 4.21 kcal/mol for Cl− and S2−, respectively, compared to the gas phase. [ABSTRACT FROM AUTHOR] |
