title: Cocrystal assembled by 1,4-diiodotetrafluorobenzene and phenothiazine based on C-I...π/N/S halogen bond and other assisting interactions.
abstract: The halogen-bonded cocrystal of 1,4-diiodotetrafluorobenzene (1,4-DITFB) with the butterfly-shape non-planar heterocyclic compound phenothiazine (PHT) was successfully assembled by the conventional solution-based method. X-ray single-crystal diffraction analysis reveals a 3:2 stoichiometric ratio for the cocrystal (1,4-DITFB/PHT), and the cocrystal structure is constructed via C-I...π, C-I...N and C-I...S halogen bonds as well as other assisting interactions (e.g. C-H...F/S hydrogen bond, C-H...H-C and C-F...F-C bonds). The small shift of the 1,4-DITFB vibrational band to lower frequencies in FT-IR and Raman spectroscopies provide evidence to confirm the existence of the halogen bond. In addition, the non-planarity of the PHT molecule in the cocrystal results in PHT emitting weak phosphorescence and relatively strong delayed fluorescence. Thus, a wide range of delayed fluorescence and weak phosphorescence could play a significant role in selecting a proper π-conjugated system to engineer functional cocrystal and luminescent materials by halogen bonds.
authors.affiliation: College of Chemistry and Material Science, Shanxi Normal University, Linfen, Shanxi 041004, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing, Beijing 100875, People's Republic of China.
authors.forename: Wei Jun
authors.initials: WJ
authors.lastname: Jin
keywords: 1,4-diiodotetrafluorobenzene; cocrystal structure; delayed fluorescence; halogen bond; phenothiazine; phosphorescence