Novel fluorescent mono- and bisboron complexes based on pyrimidine bearing beta-iminoenolate ligands were synthesized, and their fluorescence properties were investigated. The nonsubstituted and trifluoromethyl-substituted monoboron complexes showed higher fluorescence quantum yield in solid state than in solution. The dimethylamino derivative of the monoboron complex exhibited positive solvatochromism in the fluorescence spectra. The bisboron complex showed significantly higher molar absorption coefficient and red-shifted maximum absorption and maximum fluorescence wavelengths than the corresponding monoboron complex.
Strategy to enhance solid-state fluorescence and aggregation-induced emission enhancement effect in pyrimidine boron complexes
Although non-, trifluoromethyl-, and cyano-substituted derivatives showed AIEE effects, methoxy- and dimethylamino-substituted analogues resulted in relatively strong fluorescence in solution.