Synthesis and properties investigation of blue-emitting molecules based on d-π-a structures

In this paper, based on the structure model of D-π-A, carbazole and phenimidazole are used as the building blocks of blue molecules, and benzonitrile group is added to N (1) position of the imidazole ring, and tert-butyl group is added to the 3 and 6 positions of carbazole to change the length of the bridge bond. Synthesized two novel blu-ray molecular: 4 - (2 - (4 - (3, 6-2 tertiary butyl - 9 h - carbazole - 9 - base) phenyl) 1 h - fe [9, 10 - d] imidazole - 1 - base) phenyl nitrile (NCPPIM - CzBu A) and 4 - (2 - (4 ’- (3, 6-2 tertiary butyl - 9 h - carbazole - 9 - base) - [1, 1’ - biphenyls] - 4 -) 1 h - fe [9, 10 - d] imidazole - 1 - base) phenyl nitrile (NCPPIM - CzBu B). Their structure and properties were characterized and analyzed, and the influence of the bridge bond of monophenone ring and diphenyl ring on the molecular properties of blue light was explored. The experimental results showed that monophenone ring (NCPPIM-CzBu A) showed better morphological stability than diphenyl (NCPPIM-CzBu B), and NCPPIM-CzBu B had higher fluorescence quantum yield. The fluorescence quantum yield of NCPPIM-CzBu B is 9.31 % higher than that of NCPPIM-CzBu A. The results show that the reasonable selection of monophenone and diphenyl ring with bridge bond plays an important role in the synthesis of suitable blue molecules, and provides a new way for the synthesis of novel blue molecules.