Use of Unprecedented Intramolecular 1, 3-Dipolar Cycloaddition Reaction in meso-Nitrile Oxide-Containing BODIPYs as a New Pathway for the Preparation of Fused NIR Platforms.

Meso-nitrile oxide group in 1,7-Diphenyl-containing BODIPYs can be involved in highly unusual [3+2] intramolecular cycloaddition reaction with the formation of the dihydrobenzo[d]isoxazole-containing BODIPYs. Oxidation of these compounds results in the formation of unprecedented either benzisoxazole- or benzo[b]azepine-fused fully conjugated NIR absorbing BODIPYs. The photophysical properties and electronic structures of the target compounds were studied by an array of experimental and theoretical methods.