Synthesis and characteristics of novel benzothiazoyl-pyrazoline derivatives containing carbazole

Novel optical materials of trichromophore carbazole-pyrazoline have been synthesized and fully characterized by means of 1H, 13C NMR, and HRMS. The optical, electrochemical properties were also investigated. As expected, these compounds exhibited efficient emission from blue to green with high quantum yields. The solvent effect on the fluorescence characteristics of the four compounds indicates that the emission wavelength was red-shifted with the increase of solvent polarity. Quantum chemical calculations were used to obtain optimized ground-state geometry by hybrid density functional theory (B3LYP) with 6-31G* basis set, spatial distributions of the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) levels of the compounds.