Hamid Oubaha, Nicola Demitri, Joëlle Rault˗Berthelot, Philippe Dubois, Olivier Coulembier, Davide Bonifazi
J. Org. Chem., 2019, accepted.
In this paper, we describe the 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 photoswticheable azo˗borazine derivative was successfully prepared. The molecule showed reversible E/Z photoisomerization upon irradiation at the maximum of the intense ˗ absorption feature (360 nm). X˗Ray crystallographic investigations revealed a non˗planar 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).