Flash photolysis of a substituted hexaarylbiimidazole and reactions of the imidazolyl radical

Proton-controlled Action of an Imidazole as Electron Relay in a Photoredox Triad

“…S6). The spectrum is characterized by broad absorption bands around 440 nm and 650 nm 1 consistent with the spectral features of an imidazolyl radical (Im • ) [14,[21][22][23]. The large extinction coefficient at 440 nm (Δε ≈ 20,000 M −1 cm −1 by comparison with MV •+ which has ε 397 = 41,800 M −1 cm −1 ) [20] is also consistent with imidazolyl radical spectra in the literature [21].…”

Rapid, Photomediated Healing of Hexaarylbiimidazole-Based Covalently Cross-Linked Gels

“…Here, we describe an approach to address the deficiencies of contemporary, intrinsically healable cross-linked polymers by incorporating hexaarylbiimidazole (HABI) functionalities, dimers of triphenyl-substituted imidazoles, in the backbone of polymeric gels. HABIs are photosensitive groups that undergo reversible, homolytic cleavage of the carbon–nitrogen (C–N) bond between the imidazole rings to efficiently afford two teal-colored 2,4,5-triarylimidazoyl (lophyl) radicals which thermally recombine to reproduce the original imidazole dimer (see Scheme a) .…”