Direct Comparative Studies Revealing the Contribution of TADF Activity of Organic Emitters Towards Efficient Electrochemiluminescence.

Electrochemiluminescence (ECL) featuring thermally activated delayed fluorescence (TADF) properties has attracted considerable interest, showcasing their potential for 100 % exciton harvesting, which marks a significant advancement in the realm of organic ECL. However, the challenge of elucidating the precise contribution of TADF to the enhanced ECL efficiency arises due to the lack of comparative studies of organic compounds with or without efficient TADF properties. In this study, we present four carbazole-benzonitrile molecules possessing similar chemical structures and comparable exchange energy (ΔEST). Despite their comparable properties, these compounds exhibited varying TADF efficiencies, warranting a closer examination of their underlying structural and electronic characteristics governing the optical properties. Consequently, intense ECL emission was only observed from 4CzBN with a remarkable TADF efficiency, underscoring the substantial difference in the ECL signal among molecules with comparable ΔEST and similar spectral properties but varying TADF activity.

Visible-Light-Enabled Catalytic Approach to N,O-Spirocycles through Amidyl Radical Addition/Cyclization.

A rational combination of photoredox catalyst anthraquinone and hydrogen atom transfer (HAT) catalyst methyl thioglycolate allows for the rapid and straightforward conversion of a range of 2-amidated acetylenic alcohols to multifunctional N,O-spirocycles under visible light irradiation. With oxygen as the sole terminal oxidant, these reactions can be carried out efficiently at room temperature without the involvement of transition metals or strong oxidants. The successful application of this mild catalytic strategy in the late-stage functionalization of bioactive skeletons further highlights its practical value.

Visible-Light-Enabled Lanthanum-Mediated Intramolecular Epoxy-Ring Opening/Dehydrogenative Lactonization.

Catalytic C(sp3)-H functionalization has afforded great opportunities to prepare organic substances, facilitating the derivatization of complex drugs and natural molecules. This letter describes an efficient and practical protocol for lanthanum-catalyzed continuous epoxy-ring opening and oxidative dehydrogenative lactonization under visible-light irradiation. Notably, the lanthanum catalyst also acts as a photocatalyst while acting as a Lewis acid in this reaction; therefore, no additional photocatalyst is required. We can conveniently prepare a series of diverse isochromanones with oxygen-containing spirocyclic structural units under a balloon-oxygen atmosphere at room temperature. Mechanistic studies and control experiments reveal that the in situ-generated lanthanum bromide should be crucial in the reaction.

Syntheses of functionalized benzocoumarins by photoredox catalysis.

Direct functionalization of inert C(sp3)-H bonds is an attractive synthetic technology for the preparation of pharmaceutically significant compounds in modern synthetic organic chemistry. In this work, we report a new method for the synthesis of functionalized benzocoumarins through the strategy of activation of multiple C-H bonds on 2-aryl toluenes under visible-light-enabled photoredox conditions. This method has the advantages of high functional group compatibility, mild reaction conditions, and effectively avoiding the use of strong oxidants and precious metal catalysts. Detailed mechanistic investigations, including spectroscopic and electrochemical studies, support the reaction's mechanistic course.

Agaricus bisporus-Derived Glucosamine Hydrochloride Facilitates Skeletal Injury Repair through Bmp Signaling in Zebrafish Osteoporosis Model.

Glucosamine hydrochloride (GAH), one of the most basic and important derivatives of chitin, is obtained by hydrolysis of chitin in concentrated hydrochloric acid. At present, little is known about how GAH functions in skeletal development. In this report, we demonstrate that GAH, extracted from the cell wall of Agaricus bisporus, acts in a dose-dependent manner to promote not only cartilage and bone development in larvae but also caudal fin regeneration in adult fish. Furthermore, GAH treatment causes a significant increase in expression of bone-related marker genes, indicating its important role in promoting skeletal development. We show that in both larval and adult osteoporosis models induced by high iron osteogenic defects are significantly ameliorated after treatment with GAH, which regulates expression of a series of bone-related genes. Finally, we demonstrate that GAH promotes skeletal development and injury repair through bone morphogenetic protein (Bmp) signaling, and it works at the downstream of the receptor level. Taken together, our findings not only provide a strong research foundation and strategy for the screening of natural osteoporosis drugs and product development using a zebrafish model but also establish the potential for the development of Agaricus bisporus-derived GAH as a new drug for osteoporosis treatment.

Visible-Light-Enabled Oxidative Coupling of Alkenes with Dialkylformamides To Access Unsaturated Amides.

A practical and direct method for oxidative cross-coupling of alkenes with dialkylformamides is established employing visible-light-enabled photoredox catalysis. This strategy allows efficient access to diverse unsaturated amides under mild reaction conditions. The application of an appropriate diaryliodonium salt was demonstrated to be critical to the success of this process. This catalyst system is well tolerant of a variety of useful functional groups.

Visible-light-promoted oxidation/condensation of benzyl alcohols with dialkylacetamides to cinnamides.

Oxidative cross-coupling reactions of benzyl alcohols with N,N-dialkylacetamides were developed only employing oxygen as the terminal oxidant, efficiently providing a new, novel protocol for the construction of multifunctionalized cinnamides with the synergistic effects of KOH, organic photocatalyst eosin Y, and visible light irradiation at room temperature. A broad substrate scope and mild reaction conditions are the prominent features of this transformation.

Visible-Light-Enabled Oxidative Alkylation of Unactivated Alkenes with Dimethyl Sulfoxide through Concomitant 1,2-Aryl Migration.

Metal-free oxidative radical 1,2-alkylarylation of unactivated alkenes with the α-C(sp3)-H bond of dimethyl sulfoxide has been developed. This study realizes a new, conceptually novel technology for convenient construction of a variety of α-aryl-γ-methylsulfinyl ketones in good-to-excellent yields with the synergistic interactions of visible light irradiation, organic fluorophores 4CzIPN, and hypervalent iodine(III) reagent under transition-metal free conditions. A remarkable kinetic isotope effect was observed, which helped provide insight into the reaction's mechanistic course.

Synthesis of oxindoles through trifluoromethylation of N-aryl acrylamides by photoredox catalysis.

Mild and direct intramolecular oxidative aryltrifluoromethylations of activated alkenes have been established through visible light photocatalysis, affording a range of CF3-containing oxindoles or isoquinolinediones in the presence of an organic fluorophore-type photocatalyst 4CzIPN, oxygen and visible light irradiation under strong oxidant and transition metal free conditions. A variety of frequently encountered functional groups are well tolerated in this transformation.

Characterization of particulate products for aging of ethylbenzene secondary organic aerosol in the presence of ammonium sulfate seed aerosol.

Aging of secondary organic aerosol (SOA) particles formed from OH- initiated oxidation of ethylbenzene in the presence of high mass (100-300µg/m(3)) concentrations of (NH4)2SO4 seed aerosol was investigated in a home-made smog chamber in this study. The chemical composition of aged ethylbenzene SOA particles was measured using an aerosol laser time-of-flight mass spectrometer (ALTOFMS) coupled with a Fuzzy C-Means (FCM) clustering algorithm. Experimental results showed that nitrophenol, ethyl-nitrophenol, 2,4-dinitrophenol, methyl glyoxylic acid, 5-ethyl-6-oxo-2,4-hexadienoic acid, 2-ethyl-2,4-hexadiendioic acid, 2,3-dihydroxy-5-ethyl-6-oxo-4-hexenoic acid, 1H-imidazole, hydrated N-glyoxal substituted 1H-imidazole, hydrated glyoxal dimer substituted imidazole, 1H-imidazole-2-carbaldehyde, N-glyoxal substituted hydrated 1H-imidazole-2-carbaldehyde and high-molecular-weight (HMW) components were the predominant products in the aged particles. Compared to the previous aromatic SOA aging studies, imidazole compounds, which can absorb solar radiation effectively, were newly detected in aged ethylbenzene SOA in the presence of high concentrations of (NH4)2SO4 seed aerosol. These findings provide new information for discussing aromatic SOA aging mechanisms.

Visible-Light-Enabled Decarboxylative Sulfonylation of Cinnamic Acids with Sulfonylhydrazides under Transition-Metal-Free Conditions.

Decarboxylative cross-coupling reactions of cinnamic acids with sulfonylhydrazides were explored using oxygen as the sole terminal oxidant, realizing a conceptually novel technology for vinyl sulfone synthesis under the synergistic interactions of visible light irradiation, organic dye-type photocatalyst eosin Y, KI, and Cs2CO3 at room temperature.

Visible-light-promoted syntheses of ß-keto sulfones from alkynes and sulfonylhydrazides.

A variety of functionalized ß-keto sulfones were smoothly prepared through oxysulfonylation of commercially available alkynes with sulfonylhydrazides under the synergistic interactions of visible light irradiation, Ru(bpy)3Cl2 photocatalyst, oxygen, KI, and NaOAc basic additive under very mild reaction conditions.

Gold catalysis coupled with visible light stimulation: syntheses of functionalized indoles.

A judicious combination of Au-catalysis and synergistic visible-light stimulation formulates an exceptionally simple and mild reaction system capable of directly coupling anilines and alkynes to form multifunctionalized indoles.

Ag-carbenoid-initiated catalytic hydration cascades: rapid construction of functionalized bicyclo[3.3.1]nonanes.

Remarkable Ag-carbenoid-initiated enone cyclopropanation-hydrolytic fragmentation-competitive 1,2-vs-1,4 addition reaction cascades were uncovered on a range of propargylic esters tethered to cyclohexadienones, leading to the highly efficient and stereospecific construction of densely functionalized bicyclo[3.3.1]nonanes under mild conditions.

New approach to oximes through reduction of nitro compounds enabled by visible light photoredox catalysis.

A range of nitro compounds are smoothly reduced to their corresponding oximes under the synergistic effects of visible light irradiation, the Ru(bpy)3Cl2 photocatalyst, Hünig's base, Mg(ClO4)2 activation, and MeCN solvent. This remarkably mild and environmentally benign protocol, when orchestrated with classical Beckmann rearrangement, enables such high-value industrial feedstock as caprolactam to be readily accessed from simple precursor nitrocyclohexane.