Dithienoazaborine derivatives with selective π-conjugated extension late-stage functionalization

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2021-03, Vol.9 (11), p.453-461
• Main Authors: Zhang, Sikun, Yang, Xiaodong, Liu, Xu, Xu, Letian, Rao, Bin, Yan, Ni, He, Gang
• Format: Article
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d0tc05640e

The selective late-stage functionalization of BN-containing polycyclic aromatic hydrocarbons (BN-PAHs) is very challenging. Herein, dithienoazaborines ( BNDT , 3a and 3b ) were synthesized as model compounds, and two kinds of selective functionalized BNDT precursors, 4a and 4b were synthesized due to the strong polar effect of the BN bond, leading to a series of BNDT derivatives for the following coupling reactions. Based on this, two kinds of BNDT -based small molecules and oligomers with BN bonds on the conjugated main chain and side chain were synthesized accordingly. The BNDT derivatives ( 5b / 6b / 7b ) with a BN bond on the conjugated side chain showed lower LUMO energy levels and narrower band gaps than those with a BN bond on the conjugated main chain ( 5a / 6a / 7a ). Different modifications and polymerization have effects on the photophysical properties and all derivatives are highly selective to fluoride ions. This work realized a new strategy for selective late-stage functionalization of BN-PAHs with selective π-conjugated extension, laying a solid foundation for the subsequent BN chemistry and application of functionalized BN-PAHs. Two kinds of dithienoazaborine derivatives with BN bonds on the conjugated main chain and side chain were synthesized via late-stage functionalization.