Separation of halogenated benzenes enabled by investigation of halogen-? interactions with carbon materials.

ABSTRACT: The halogen-? (X-?) interaction is an intermolecular interaction between the electron-poor region of bonded halogen atoms and aromatic rings. We report an experimental evaluation of the halogen-? (X-?) interaction using liquid chromatography with carbon-material coated columns providing strong ? interactions in the normal phase mode. A C70-fullerene (C70)-coated column showed higher retentions for halogenated benzenes as the number of halogen substitutions increased as a result of X-? interactions. In addition, the strength of the X-? interaction increased in the order of F < Cl < Br < I. Changes to the UV absorption of C70 and the brominated benzenes suggested that the intermolecular interaction changed from the ?-? interaction to X-? interaction as the number of bromo substitutions increased. Computer simulations also showed that the difference in dipole moments among structural isomers affected the strength of the ?-? interaction. Furthermore, we concluded from small peak shifts in 1H NMR and from computer simulations that the orbital interaction contributes to the X-? interactions. Finally, we succeeded in the one-pot separation of all isomers of brominated benzenes using the C70-coated column by optimizing the mobile phase conditions.

SUBMITTER: Kanao E 

PROVIDER: S-EPMC7067276 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature