Electron Spin Resonance of Difluorobiphenyls in the Phosphorescent Triplet States. s-cis and s-trans Conformers and Fluorine Hyperfine Structure

Article abstract of DOI:10.1016/0022-2364(89)90372-7

Electron spin resonance spectra of 2,2'-, 3,3'- and 4,4'-difluorobiphenyls (2DFBP, 3DFBP, and 4DFBP, respectively) in their phosphorescent triplet states have been studied in various matrices at 77 K.Two sets of peaks corresponding to the s-cis and s-trans conformers are observed for 2DFBP and 3DFBP.By using a stretched poly(vinyl alcohol) film as a host, the observed individual peaks are assigned.The 19F hyperfine splitting is obtained for 2DFBP and 4DFBP with a microwave magnetic field parallel to an external magnetic field (B<*>B_rf), which is different from the conventional resonance condition of B<*>B_rf.