RESUMO
Two novel deep-blue multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters, 1B-CzCrs and 2B-CzCrs, containing a fused carbazole unit were synthesized. The carbazole contributed to the emergence of TADF in these small molecules. Particularly, organic light-emitting diodes with 1B-CzCrs doped in the mCP host achieve a maximum external quantum efficiency of 12.8% at CIE coordinates of (0.146, 0.062).
RESUMO
Optochemistry, an emerging pharmacologic approach in which light is used to selectively activate or deactivate molecules, has the potential to alleviate symptoms, cure diseases, and improve quality of life while preventing uncontrolled drug effects. The development of in-vivo applications for optochemistry to render brain cells photoresponsive without relying on genetic engineering has been progressing slowly. The nucleus accumbens (NAc) is a region for the regulation of slow-wave sleep (SWS) through the integration of motivational stimuli. Adenosine emerges as a promising candidate molecule for activating indirect pathway neurons of the NAc expressing adenosine A2A receptors (A2ARs) to induce SWS. Here, we developed a brain-permeable positive allosteric modulator of A2ARs (A2AR PAM) that can be rapidly photoactivated with visible light (λ > 400 nm) and used it optoallosterically to induce SWS in the NAc of freely behaving male mice by increasing the activity of extracellular adenosine derived from astrocytic and neuronal activity.
Assuntos
Adenosina , Núcleo Accumbens , Receptor A2A de Adenosina , Sono de Ondas Lentas , Animais , Núcleo Accumbens/metabolismo , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/fisiologia , Masculino , Receptor A2A de Adenosina/metabolismo , Receptor A2A de Adenosina/genética , Camundongos , Adenosina/metabolismo , Adenosina/farmacologia , Regulação Alostérica , Sono de Ondas Lentas/fisiologia , Sono de Ondas Lentas/efeitos dos fármacos , Astrócitos/metabolismo , Astrócitos/efeitos dos fármacos , Luz , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Humanos , Agonistas do Receptor A2 de Adenosina/farmacologiaRESUMO
Photon-upconversion in organic molecular systems is one of the promising technologies for future energy harvesting systems because these systems can generate excitons that possess higher energy than excitation energy. The photon-upconversion caused by absorbing ambient heat as additional energy is particularly interesting because it could ideally provide a light-driving cooling system. However, only a few organic molecular systems have been reported. Here, we report the anti-Stokes photoluminescence (ASPL) derived from hot-band absorption in a series of multi-resonance-type thermally-activated delayed fluorescence (MR-TADF) molecules. The MR-TADF molecules exhibited an anti-Stokes shift of approximately 0.1â eV with a high PL quantum yield in the solution state. The anti-Stokes shift corresponded well to the 1-0 vibration transition from the ground state to the excited singlet state, and we further evaluated a correlation between the activation energy for the ASPL intensity and the TADF process. Our demonstration underlines that MR-TADF molecules have become a novel class of ASPL materials for various future applications, such as light-driving cooling systems.
RESUMO
In this study, we propose that the trifluoromethylated thermally activated delayed fluorescent molecule 4[Cz(CF3)2]IPN is a versatile organic photocatalyst that can be used for electron-transfer-driven reactions requiring a photocatalyst with high oxidizing power and energy-transfer-driven reactions that require an Ir photocatalyst. 4[Cz(CF3)2]IPN was used in radical reactions via electron transfer and dearomative cycloaddition reactions via energy transfer.
Assuntos
Corantes , Elétrons , Fluorescência , Transporte de Elétrons , Transferência de EnergiaRESUMO
Photoremovable protecting groups (PPGs) represent one of the main contemporary implementations of photochemistry in diverse fields of research and practical applications. For the past half century, organic and metal-complex PPGs were considered mutually exclusive classes, each of which provided unique sets of physical and chemical properties thanks to their distinctive structures. Here, we introduce the meso-methylporphyrin group as a prototype hybrid-class PPG that unites traditionally exclusive elements of organic and metal-complex PPGs within a single structure. We show that the porphyrin scaffold allows extensive modularity by functional separation of the metal-binding chromophore and up to four sites of leaving group release. The insertion of metal ions can be used to tune their spectroscopic, photochemical, and biological properties. We provide a detailed description of the photoreaction mechanism studied by steady-state and transient absorption spectroscopies and quantum-chemical calculations. Our approach applied herein could facilitate access to a hitherto untapped chemical space of potential PPG scaffolds.
Assuntos
Porfirinas , Íons , Luz , Metais , FotoquímicaRESUMO
The intermolecular dearomative cycloaddition of acidified bicyclic azaarenes with olefins was recently reported. We report here the crucial role of the acid in the dearomative photocycloaddition of quinolines to olefins. Experimental and theoretical results show that the key role of the protonation of quinolines is not to promote the energy transfer but to enhance the reactivity of the triplet state of quinolines toward olefins.
RESUMO
A caged carboxylic acid with a novel two-photon (TP)-responsive donor-π-donor coumarin backbone with a quadrupolar nature was designed and synthesized in this study. The newly synthesized coumarin derivative showed a strong one-photon (OP) absorption band (ε ≈ 29000 cm-1 M-1) in the visible region (>â¼400 nm). Time-dependent density functional theory calculations predicted a sizable TP absorption cross-section with a maximum at â¼650 nm significantly lager than that related to the OP absorption band. This is confirmed experimentally using TP excited fluorescence in the fs regime that leads to TP absorption cross-section of 18 and 5.6 GM at 680 and 760 nm, respectively. The OP photolysis (400 nm) and near-infrared-TP photolysis (750 nm) of the caged benzoic acid resulted in a clean formation of benzoic acid and an aldehyde.