title: Strategy to enhance solid-state fluorescence and aggregation-induced emission enhancement effect in pyrimidine boron complexes.
abstract: The synthesis and the solution/solid-state fluorescence properties of pyrimidine-based monoboron complexes differing in terms of the substituents [either two fluorine atoms (BF2 complex) or two phenyl groups (BPh2 complex)] on the boron atom are reported herein. Unrestricted C-Ar intramolecular rotation in the non-, trifluoromethyl-, and cyano-substituted derivatives resulted in negligible fluorescence in solution. On the other hand, methoxy- and dimethylamino-substituted analogues caused the restriction of the C-Ar intramolecular rotation and consequently resulted in relatively strong fluorescence in solution. The non-, trifluoromethyl-, and cyano-substituted derivatives showed a pronounced aggregation-induced emission enhancement effect. Dimethylamino-substituted derivatives exhibited solvatochromism in the fluorescence spectra. Substitution with BPh2 effectively enhanced the fluorescence quantum yield compared to the corresponding BF2 complexes in the solid-state.
authors.affiliation: Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan. kubota@gifu-u.ac.jp matsuim@gifu-u.ac.jp.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kubota
authors.forename: Kouhei
authors.initials: K
authors.lastname: Kasatani
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takai
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Funabiki
authors.forename: Masaki
authors.initials: M
authors.lastname: Matsui