Harnessing reductive BF2-complexation via Ru(ii)-catalyzed N–O cleavage of isoxazoles

Developed here is a highly fluorescent organic N,O bidentate BF2 complex from isoxazole in the presence of a Ru(ii) catalyst. Herein, the complexation proceeds via a selective N–O cleavage of the isoxazole ring. The complex shows absorption (λmax,abs) in the range of 352–363 nm with an extinction coefficient (ϵ) in the range of 8000–64 000 M−1 cm−1, and fluorescence emission (λmax,em) in the range of 413–485 nm with a Stokes shift of 61–125 nm having quantum yield up to 33%. Apart from the solution state, the solid BF2 complex 2u exhibits absorption at 405 nm and strong fluorescence emission at 550 nm with a quantum yield of 26.9%.