Tuning the Electro‐Optical Properties of Mixed‐Halide Trityl Radicals Bearing <i>para</i>‐Brominated Positions through Halogen Substitution

Mesto, Davide; Dai, Yasi; Dibenedetto, Carlo Nazareno; Punzi, Angela; Krajčovič, Jozef; Striccoli, Marinella; Negri, Fabrizia; Blasi, Davide

doi:10.1002/ejoc.202201030

Cited by 7 publications

(7 citation statements)

References 34 publications

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“…[29] Indeed, polyhalogenated trityl radicals can achieve long-wavelength emission without the need of an extended conjugated system. [30,31] In addition, it is possible to further red-shift radical emission into the biological transparency window (650 -950 nm) through the formation of excimers. These excimers, obtained by dispersing radical species in rigid hosts (generally the closed-shell radical precursor) have been studied during the last years due to the possibility to modulate their association/dissociation via the application of an external magnetic field at liquid helium temperature.…”

Section: Introductionmentioning

confidence: 99%

Ratiometric Nanothermometer Based on a Radical Excimer for In Vivo Sensing

Blasi

Gonzalez‐Pato

Rodrı́guez

et al. 2023

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Ratiometric fluorescent nanothermometers with near‐infrared emission play an important role in in vivo sensing since they can be used as intracellular thermal sensing probes with high spatial resolution and high sensitivity, to investigate cellular functions of interest in diagnosis and therapy, where current approaches are not effective. Herein, the temperature‐dependent fluorescence of organic nanoparticles is designed, synthesized, and studied based on the dual emission, generated by monomer and excimer species, of the tris(2,4,6‐trichlorophenyl)methyl radical (TTM) doping organic nanoparticles (TTMd‐ONPs), made of optically neutral tris(2,4,6‐trichlorophenyl)methane (TTM‐αH), acting as a matrix. The excimer emission intensity of TTMd‐ONPs decreases with increasing temperatures whereas the monomer emission is almost independent and can be used as an internal reference. TTMd‐ONPs show a great temperature sensitivity (3.4% K−1 at 328 K) and a wide temperature response at ambient conditions with excellent reversibility and high colloidal stability. In addition, TTMd‐ONPs are not cytotoxic and their ratiometric outputs are unaffected by changes in the environment. Individual TTMd‐ONPs are able to sense temperature changes at the nano‐microscale. In vivo thermometry experiments in Caenorhabditis elegans (C. elegans) worms show that TTMd‐ONPs can locally monitor internal body temperature changes with spatio‐temporal resolution and high sensitivity, offering multiple applications in the biological nanothermometry field.

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Section: Introductionmentioning

confidence: 99%

Ratiometric Nanothermometer Based on a Radical Excimer for In Vivo Sensing

Blasi

Gonzalez‐Pato

Rodrı́guez

et al. 2023

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“…The enantiomers can be separated into the M-and P-propellers, which exhibit circular dichroism as well as circularly polarized emission. However, the photoluminescence quantum yields ϕ of such halogenated trityl radicals are marginal in solution, especially for heavier halides (bromine and iodine), [10][11][12] which are the ones to exist as stable enantiomers at room temperature. [7] We have recently reported the synthesis of a mono-iodinated chloro-trityl radical with ϕ = 2.8%, somewhat lower than the tris(2,4,6-trichlorophenyl)methyl (TTM) radical ϕ = 3%.…”

Section: Introductionmentioning

confidence: 99%

Aza[7]helicene Functionalized Triphenylmethyl Radicals with Circularly Polarized Doublet Emission

Gross,

Zhang,

Arnold

et al. 2023

Advanced Optical Materials

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Synthesis and characterization of configurationally stable chiral aza[7]helicene‐functionalized trityl radicals are reported. To overcome the problem of incomplete radical formation after coupling the trityl radical to the chiral aza[7]helicenes in a nucleophilic aromatic substitution, this study instead employs Pd‐catalyzed C‐N cross‐coupling. In contrast to the conventional approach, the open‐shell character is retained allowing quantitative yield of the radical. The obtained dinaphthocarbazole and diphenanthrocarbazol‐functionalized tris(trichlorophenyl)methyl (TTM) radicals can be separated into the respective enantiomers. The resulting chiral radicals exhibit photoluminescence quantum yields as high as 43% and circularly polarized luminescence. Time‐dependent density functional theory (TD‐DFT) calculations support the experimental findings. The newly reported aza[7]helicene‐based radicals hold promise for advanced optoelectronic as well as quantum technological applications.

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“…Negri, Blasi, and co-workers reported polyhalogenated TArM radicals, TBr 6 Cl 5 M and TBr 2 F 8 Cl 5 M (Chart 6), bearing one perchlorobenzene and two para-brominated benzene moieties. 199 TBr 6 Cl 5 M in cyclohexane showed photoluminescence with λ em , ϕ em , and τ of 599 nm, 0.02 ± 0.004, and 3.6 ± 0.2 ns, respectively (Figure 22a). These values are similar to those of other brominated luminescent TArM radicals.…”

Section: Effects Of Halogen Atoms Other Than Chlorinementioning

confidence: 99%

Section: Luminescent Organic Radicalsmentioning

confidence: 99%

Luminescent Radicals

Mizuno,

Matsuoka,

Mibu

et al. 2024

Chem. Rev.

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Organic radicals are attracting increasing interest as a new class of molecular emitters. They demonstrate electronic excitation and relaxation dynamics based on their doublet or higher multiplet spin states, which are different from those based on singlet–triplet manifolds of conventional closed-shell molecules. Recent studies have disclosed luminescence properties and excited state dynamics unique to radicals, such as highly efficient electron–photon conversion in OLEDs, NIR emission, magnetoluminescence, an absence of heavy atom effect, and spin-dependent and spin-selective dynamics. These are difficult or sometimes impossible to achieve with closed-shell luminophores. This review focuses on luminescent organic radicals as an emerging photofunctional molecular system, and introduces the material developments, fundamental properties including luminescence, and photofunctions. Materials covered in this review range from monoradicals, radical oligomers, and radical polymers to metal complexes with radical ligands demonstrating radical-involved emission. In addition to stable radicals, transiently formed radicals generated in situ by external stimuli are introduced. This review shows that luminescent organic radicals have great potential to expand the chemical and spin spaces of luminescent molecular materials and thus broaden their applicability to photofunctional systems.

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Tuning the Electro‐Optical Properties of Mixed‐Halide Trityl Radicals Bearing para‐Brominated Positions through Halogen Substitution

Cited by 7 publications

References 34 publications

Ratiometric Nanothermometer Based on a Radical Excimer for In Vivo Sensing

Ratiometric Nanothermometer Based on a Radical Excimer for In Vivo Sensing

Aza[7]helicene Functionalized Triphenylmethyl Radicals with Circularly Polarized Doublet Emission

Luminescent Radicals

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