Schmid, Lucius; Glaser, Felix; Schaer, Raoul; Wenger, Oliver S. published the artcile< High Triplet Energy Iridium(III) Isocyanoborato Complex for Photochemical Upconversion, Photoredox and Energy Transfer Catalysis>, Quality Control of 396092-82-3, the main research area is photochem upconversion photoredox energy transfer catalysis; High Triplet Energy Iridium Isocyanoborato Complex.
Cyclometalated Ir(III) complexes are often chosen as catalysts for challenging photoredox and triplet-triplet-energy-transfer (TTET) catalyzed reactions, and they are of interest for upconversion into the UV spectral range. However, the triplet energies of commonly employed Ir(III) photosensitizers are typically limited to values around 2.5-2.75 eV. Here, we report on a new Ir(III) luminophore, with an unusually high triplet energy near 3.0 eV owing to the modification of a previously reported Ir(III) complex with isocyanoborato ligands. Compared to a nonborylated cyanido precursor complex, the introduction of B(C6F5)3 units in the second coordination sphere results in substantially improved photophys. properties, in particular a high luminescence quantum yield (0.87) and a long excited-state lifetime (13.0 μs), in addition to the high triplet energy. These favorable properties (including good long-term photostability) facilitate exceptionally challenging organic triplet photoreactions and (sensitized) triplet-triplet annihilation upconversion to a fluorescent singlet excited state beyond 4 eV, unusually deep in the UV region. The new Ir(III) complex photocatalyzes a sigmatropic shift and [2 + 2] cycloaddition reactions that are unattainable with common transition metal-based photosensitizers. In the presence of a sacrificial electron donor, it furthermore is applicable to demanding photoreductions, including dehalogenations, detosylations, and the degradation of a lignin model substrate. Our study demonstrates how rational ligand design of transition-metal complexes (including underexplored second coordination sphere effects) can be used to enhance their photophys. properties and thereby broaden their application potential in solar energy conversion and synthetic photochem.
Journal of the American Chemical Society published new progress about [2+2] Cycloaddition reaction. 396092-82-3 belongs to class pyridine-derivatives, and the molecular formula is C7H9BrN2, Quality Control of 396092-82-3.