Abstract : In this paper, we describe synthetic routes for preparing a novel switchable BNC-based chromophore, composed of a borazine core peripherally functionalized with azobenzene moieties. Capitalizing on the Pd-catalyzed Suzuki cross-coupling reaction between a tris-triflate borazine and an organoboron azobenzene derivative, a photoswtichable azo-borazine derivative was successfully prepared. The molecule showed reversible E/Z photoisomerization upon irradiation at the maximum of the intense π–π* absorption feature (360 nm). X-ray crystallographic investigations revealed a nonplanar orientation of the three azobenzene moieties and the trans configuration of the −N═N– bonds. Building on the synthetic versatility of the borazine-azobenzene derivative, we used this photoactive scaffold to engineer soluble BN-doped polythiophene polymers. Photophysical characterization performed in solvents of different polarity suggested that the polymer undergoes intramolecular charge transfer (ICT).
Hamid Oubaha, Nicola Demitri, Joelle Rault-Berthelot, Philippe Dubois, Olivier Coulembier, et al.. Photoactive Boron-Nitrogen-Carbon Hybrids: From Azo-borazines to Polymeric Materials. Journal of Organic Chemistry, American Chemical Society, 2019, 84 (14), pp.9101-9116. ⟨10.1021/acs.joc.9b01046⟩. ⟨hal-02278423⟩
