Enhancement of fluorescence and photostability of luminescent radicals by quadruple addition of phenyl groups

Abstract

Quadruple addition of phenyl groups to a diphenylpyridylmethane skeleton was achieved. The derived (3,5-difluoro-4-pyridyl)bis(2,6-dichloro-3,4-diphenylphenyl)methyl radical (Ph4-F2PyBTM) displayed superior luminescent properties to the previously reported organic diphenylpyridylmethyl radicals in various organic...

Polyconjugated Materials for Printed (Opto)Electronics: Introducing Sustainability

“…Recently, we demonstrated that it is possible to prepare more heavily functionalized persistent radicals using the same chemistry, eventually reaching unprecedented stabilities and luminescence efficiencies. 134…”

“…Recently, we demonstrated that it is possible to prepare more heavily functionalized persistent radicals using the same chemistry, eventually reaching unprecedented stabilities and luminescence efficiencies. 134 Similarly, when we targeted the highly conjugated, branched spirobifluorene derivative 4DPA -a molecule enabling for the first time the observation of intramolecular triplet-triplet annihilation -the micellar approach was the only one capable of providing the required 4 SM couplings leading to the target derivative in useful yields Scheme 5. 135 Micellar methods allow the preparation of relatively complex molecules in high yield and on an industrially relevant scale, as we demonstrated with the synthesis of the fluorescent material MPDTBOP (5,6-diphenoxy-4,7-bis[5-(2,6-dimethylphenyl)-2-thienyl]benzo[c]1,2,5-thiadiazole), which we made in 78% overall yield in five steps, four of them using water as the solvent.…”

“…Recently, we demonstrated that it is possible to prepare more heavily functionalized persistent radicals using the same chemistry, eventually reaching unprecedented stabilities and luminescence efficiencies. 134 Similarly, when we targeted the highly conjugated, branched spirobifluorene derivative 4DPA -a molecule enabling for the first time the observation of intramolecular Triplet-Triplet annihilation -the micellar approach was the only one capable of providing the required 4 S-M couplings leading to the target derivative in useful yields. 135 Scheme 7.…”

Luminescent Radicals

“…Mattielo, Hattori, and co-workers further substituted the F 2 PyBTM skeleton with three or four aromatic groups . Compared with F 2 PyBTM, its derivatives F 2 PyBTM-Ph 4 and F 2 PyBTM-(PhOMe) 4 (Chart )which have two aryl groups each at the para - and meta -positions of the benzene ringsshowed bathochromically shifted lowest-energy absorption and photoluminescence with enhanced ϕ em in cyclohexane (0.06 for F 2 PyBTM-Ph 4 and 0.17 for F 2 PyBTM-(PhOMe) 4 ).…”

A feasible strategy to obtain air-stable triphenylamine radicals in the solid state by introducing conjugated donor–acceptor modules

“…[10][11][12][13] To our knowledge, most of the reported TPA radicals are obtained by chemical oxidation and mainly exist in the solid state of crystals containing metal complex anions in the solid state, 11,[14][15][16][17][18] which would severely limit their applications as organic optoelectronic materials. Conversely, purely organic radicals were preferred in organic magnets, [19][20][21][22] conductive materials, 23,24 batteries, 25,26 organic-light emitting diodes (OLEDs), 27,28 and other fields. Nonetheless, to date, few stable radicals in the solid state, especially air-stable radicals, have been reported.…”