Synthesis, photophysical properties and NIR photochromism of photoresponsive difluoroboron β-diketonate complex based on dithienylethene unit

The development of stimuli-responsive difluoroboron beta-diketonate materials has attracted more and more attention for their potential application in optoelectronics and functional bio-materials. In this study, we have designed and synthesized a novel photoresponsive dithienylethene-containing difluoroboron beta-diketonate complex 1 by Knoevenagel condensation reaction. Its structure have been confirmed by H-1 NMR, C-13 NMR and HRMS (ESI). And it exhibited solvent-dependent photophysical properties in solution before visible light irradiation. Subsequently, photochromism of 1 was investigated in solution, and it was found that 1 revealed solvent-dependent and visible light-triggered NIR photochromic behaviors. Moreover, it also displayed excellent fluorescence switching behavior and photochromism in the film state upon visible light irradiation. Accordingly, the dithienylethene 1 may be acted as a novel visible light-responsive fluorescence dyes in optoelectronic materials.