Synthesis of Benzo[c]cinnolinium Salts from 2-Azobiaryls by Copper(II) or Electrochemical Oxidation.

Synthesis of benzo[c]cinnolinium salts by copper(II)-promoted or electrochemical oxidation of 2-azobiaryls is described. A variety of diversely functionalized benzo[c]cinnolinium salts were easily constructed by this strategy with excellent functional group tolerance and high efficiency. An interesting fluorescence centered at 571 nm is revealed by a benzo[c]cinnolinium salt with electron push-pull substitutions. The mechanism is proposed to go through single-electron transfer driven by oxidant and intramolecular cyclization via nucleophilic addition, followed by an anion exchange.

Crystal structure and fluorescence of 1-[8-phenyl-9-(phenyl-ethyn-yl)-4H-benzo[def]carbazol-4-yl]ethan-1-one.

The crystal of the title compound, C60H38N2O2, which crystallizes in the monoclinic space group P21/n, was obtained by thermal evaporation of a 1:1 di-chloro-methane and hexa-nes solution of the pure compound. The crystal structure is stabilized by π-π inter-actions between benzo[def]carbazole moieties and carbon-yl-carbonyl inter-actions between the two acetyl groups.

Promoting the Efficiency and Stability of Nonfullerene Organic Photovoltaics by Incorporating Open-Cage [60]Fullerenes in the Nonfullerene Nanocrystallites.

The device efficiency of PM6:Y6-based nonfullerene organic solar cells is fast advanced recently. To maintain organic solar cells (OSCs) with high power conversion efficiency over 16% in long-term operation, however, remains a challenge. Here, a novel non-volatile additive, an open-cage [60]fullerene (8OC60Me), is incorporated into PM6:Y6-based OSCs for high-performance with high durability. With optimized addition of 1.0 wt % 8OC60Me, the PCE value of PM6:Y6/8OC60Me OSCs can be promoted to 16.5% from 15.0%. Most strikingly, such a high PCE performance can maintain nearly 100% for over 500 h at room temperature; at an elevated operation temperature of 80 °C, the PCE can be stabilized above 15.0% after 45 h of operation. Grazing incidence small- and wide- angle X-ray scattering studies reveal improved orientation and crystallinity of Y6 in a fractal-like network structure of PM6 in PM6:Y6/8OC60Me films under in situ annealing, parallel to the enhanced electron mobility. Analysis of charge distributions lines up possible van der Waals interaction between the thienyl/carbonyl moiety of 8OC60Me and difluorophenyl-based FIC-end groups of Y6. This result is of great contrast to those devices with the best-selling PC61BM as the additives─8OC60Me might be of interest to be incorporated into future Y6-based OSCs for concomitantly improved PCE and excellent stability.

Pd-Catalyzed Redox-Neutral C-N Coupling Reaction of Iminoquinones with Electron-Deficient Alkenes without External Oxidants: Access of Tertiary (E)-Enamines and Application to the Synthesis of Indoles and Quinolin-4-ones.

A novel and efficient reductive N-alkenylation of iminoquinones with electron-deficient olefins has been successfully developed by Pd(II)-catalyzed redox-neutral reactions, which provides a synthesis of tertiary (E)-enamines. We further demonstrate that the tertiary enamines can be converted to multifarious N-heterocyclic compounds, indoles, and quinolones in good yields.

Cascade One-Pot Synthesis of Orange-Red-Fluorescent Polycyclic Cinnolino[2,3-f]phenanthridin-9-ium Salts by Palladium(II)-Catalyzed C-H Bond Activation of 2-Azobiaryl Compounds and Alkenes.

Quaternary ammonium salts were synthesized in moderate to good yields through double oxidative C-H bond activation on azobenzenes. The mechanism of the highly regioselective reaction of 2-azobiaryls with alkenes to give orange-red-fluorescent cinnolino[2,3-f]phenanthridin-9-ium salts and 15H-cinnolino[2,3-f]phenanthridin-9-ium-10-ide is proposed to involve ortho C-H olefination of the 2-azobiaryl compound with the alkene, intramolecular aza-Michael addition, concerted metalation-deprotonation (CMD), reductive elimination, and oxidation.

Synthesis, Isolation, and Characterization of Mono- and Bis-norbornene-Annulated Biarylamines through Pseudo-Catellani Intermediates.

A palladium-catalyzed C-H functionalization of an external ring of N-acyl 2-aminobiaryl with bicyclo[2.2.1]hept-2-ene (norbornene) via multiple C-H bond activations was developed. This study is the first report of the formation of bis-norbornene annulated biarylamines isomers ( syn-3a'/ anti-3a' = 36:64) from multiple C-H bond functionalizations. Additionally, nondirected C-H bond functionalization at the C-4' position with alkenes rendered complete C-H functionalization of five C-H bonds that formed a stable hexasubstituted benzene ring.

Palladium(II)-Catalyzed Mono- and Bis-alkenylation of N-Acetyl-2-aminobiaryls through Regioselective C-H Bond Activation.

We developed palladium-catalyzed oxidative coupling of olefins with N-acyl 2-aminobiaryls through a sequence of ortho C-H bond activation/alkene insertion/reductive elimination. Furthermore, we controlled the selectivity of mono- and bis-alkenylation products with the solvent effect. The developed protocol was promising for a broad substrate scope ranging from activated olefins with a wide variety of functional groups to unactivated olefins.