Modulating Aryl Azide Photolysis: Synthesis of a Room‐Temperature Phosphorescent Carboline in Cucurbit[7]uril Host

Abstract

Cucurbit[7]uril (CB7), a supramolecular host, is employed to control the pathway of photolysis of an aryl azide in an aqueous medium. Normally, photolysis of aryl azides in bulk water culminates predominantly in the formation of azepine derivatives via intramolecular rearrangement. Remarkably, however, when this process unfolds within the protective confinement of the CB7 cavity, it results in a carboline derivative, as a consequence of a C─H amination reaction. The resulting carboline caged by CB7 reveals long‐lived room temperature phosphorescence (RTP) in the solid state, with lifetimes extending up to 2.1 s. These findings underscore the potential of supramolecular hosts to modulate the photolysis of aryl azides and to facilitate novel phosphorescent materials.

Reversing the stereoselectivity of intramolecular [2+2] photocycloaddition utilizing cucurbit[8]uril as a molecular flask

“…20,21 Their nanocavities are excellent binders for hydrophobic molecules in aqueous environments, while the carbonyl-fringed portal regions provide an additional driving force for binding cationic guests. As a result, CB n have been employed as both reaction vessels and supramolecular catalysts 22,23 to control or accelerate the outcome of organic reactions such as 1,3-dipolar Huisgen cycloaddition, 24–26 Diels–Alder reaction, and photodimerization. 27–29…”