Diversity-oriented synthesis enables the rapid development of quinoxaline-based bis-boron fluorophores: photophysical properties and sensing applications

Abstract

Organoboron fluorophores have emerged as promising functional dyes with versatile photophysical properties. The innovative strategy of incorporating multiple boron coordination units has significantly broadened their application potential. Herein, a new array of quinoxaline-based organoboron fluorophores was designed and developed. The bis-boron coordination anchored core displays remarkable stability, and enables diversity-oriented post-complexation functionalization (PCF) through various transition metal catalyzed couplings, thereby facilitating the subsequent structure–activity relationship (SAR) study. The obtained innovative dyes exhibit wavelength-tunable fluorescence ranging from 490 nm to 600 nm, with large Stokes shifts and quantum yields up to 91% in toluene. Furthermore, the practical applications of the methylthio-substituted bis(BF₂) complexes as the highly efficient hypochlorite detection probes are demonstrated.