화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.118, No.4, 1080-1087, 2014
The Competition of sigma-Hole center dot center dot center dot Cl- and pi-Hole center dot center dot center dot Cl- Bonds between C6F5X (X = F, Cl, Br, I) and the Chloride Anion and Its Potential Application in Separation Science
On the basis of the varying amplitude and patterns of the F-19 NMR chemical shift of C6F5X (X = F, Cl, Br, I) in the presence of chloride anions, bonding models of C6F5X center dot Cl- complexes were tentatively established, and the relevant binding constants were obtained. Interaction models were also simulated using computational chemistry. The theoretical computations were found to be highly consistent with the results of the experiments. The results show that C6F5Br/C6F5I and Cl- were prone to forming C-I/Br center dot center dot center dot Cl- sigma-hole bonding complexes with the F-19 NMR signal shifting to higher fields, and the interaction strength of the C6F5I center dot center dot center dot Cl- sigma-hole bond was larger than that of C6F5Br center dot center dot center dot Cl-; C6F6/C6F5Cl and Cl- formed pi-hole center dot center dot center dot Cl- bonding complexes with the signal shifting to lower fields, and the interaction strength of C6F6 was larger than that of C6F5Cl. The binding constant of the C6F5I center dot center dot center dot Cl- sigma-hole bonding complex is 38.0 M-1, which is nearly 165- to 345-fold larger than that of the other C6F5X center dot Cl- complexes. On the basis of the above results, solid phase extraction experiments were designed, and the results demonstrated the potential applicability of the C-I center dot center dot center dot Cl- sigma-hole bond in separation science.