Synthesis of Tetradeca- and Pentadeca(organo)[60]fullerenes Containing Unique Photo- and Electroluminescent π‑Conjugated Systems

Dianions of deca­(phenyl)[60]­fullerene–bis­(cyclopentadienyl ruthenium) complex, (C₆₀Ph₁₀)­(RuCp)₂ (<b>1a</b>), and dimethylated deca­(phenyl)[60]­fullerene, C₆₀Ph₁₀Me₂ (<b>1b</b>), reacted with benzyl bromide to produce [C₆₀Ph₁₀(CH₂Ph₂)₂]­(RuCp)₂ (<b>3a</b> and <b>4a</b>) and tetradeca­(organo)[60]­fullerenes C₆₀Ph₁₀(CH₂Ph₂)₂Me₂ (<b>3b</b> and <b>4b</b>), respectively (Compounds <b>3</b> and <b>4</b> refer to <i>C</i>_2<i>v</i> and <i>C</i>₁ symmetric compounds, respectively.). Nucleophilic addition of benzylmagnesium chloride with the <i>C</i>₁ symmetric compounds <b>4a</b> and <b>4b</b> yielded [C₆₀Ph₁₀(CH₂Ph₂)₃H]­(RuCp)₂ (<b>5a</b>) and pentadeca­(organo)[60]­fullerenes C₆₀Ph₁₀(CH₂Ph₂)₃Me₂H (<b>5b</b>), respectively. Products were structurally characterized by X-ray crystallographic analysis of diruthenium complexes <b>3a</b>, <b>4a</b>, and <b>5a</b>. These X-ray studies revealed that compounds <b>3</b>, <b>4</b>, and <b>5</b> have unique π-conjugated systems consisting of doubly bridged triphenylene dimer, triphenylene–benzoacenaphthylene, and triphenylene–biphenyl structures, respectively. Quantum mechanical calculations suggested that these π-conjugated systems are aromatic. Containing no metal atom, methylated derivatives <b>3b</b>, <b>4b</b>, and <b>5b</b> exhibited green, pale yellow, and turquoise blue emissions with quantum yields of 0.066, 0.12, and 0.24, respectively. The application of these materials in organic light-emitting diodes was demonstrated

Nickel-Catalyzed Allylic C(sp³)–F Bond Activation of Trifluoromethyl Groups via β‑Fluorine Elimination: Synthesis of Difluoro-1,4-dienes

The nickel-catalyzed defluorinative coupling of 2-trifluoromethyl-1-alkenes and alkynes with the aid of Et₃SiH provides 1,1-difluoro-1,4-dienes under mild reaction conditions. This reaction involves selective allylic C­(sp³)–F bond activation via β-fluorine elimination from nickelacyclopentenes

Method for the Synthesis of Dibenzo[<i>g</i>,<i>p</i>]Chrysenes: Domino Friedel–Crafts-Type Cyclization of Difluoroethenes Bearing Two Biaryl Groups

Dibenzo­[<i>g</i>,<i>p</i>]­chrysenes were readily synthesized via the superacid- or TiF₄-mediated domino Friedel–Crafts-type cyclization of 1,1-difluoroethenes bearing two biaryl groups, which were easily prepared via the Suzuki–Miyaura coupling of 1,1-difluoro-2,2-diiodoethene or 1-(biphenyl-2-yl)-1-bromo-2,2-difluoroethene. Using this approach, the activation of both vinylic and aromatic C–F bonds was successfully achieved to make new C–C bonds

New series of avenanthramides in oat seed

<div><p>Avenanthramides are characteristic constituents of oat seeds. We analyzed the methanol extract of oat seeds by HPLC and detected three compounds 1, 2, and 3 eluted at retention times similar to avenanthramides. The three compounds were purified by column chromatography and HPLC. Spectroscopic analyses of 1, 2, and 3 suggested that they are amides of 4,5-dihydroxyanthranilic acid with caffeic, <i>p</i>-coumaric, and ferulic acids, respectively. Their identities were confirmed by comparing spectra and chromatographic behavior with compounds synthesized from 4,5-dihydroxyanthranilic acid and <i>N</i>-hyrdroxysuccinimide esters of hydroxycinnamic acids. LC-MS/MS analysis with multiple reaction monitoring showed that the amounts of 1, 2, and 3 were 16.5–26.9% of corresponding avenanthamides with 5-hydroxyanthranilic acid. Compounds 1, 2, and 3 showed stronger 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity than the corresponding avenanthramides with 5-hydroxyanthranilic acid, indicating the involvement of 4,5-dihydroxyanthranilic acid moiety in the scavenging of DPPH radicals.</p></div

Two-Step Synthesis of Difluoromethyl-Substituted 2,3‑Dihydrobenzoheteroles

3-Difluoromethylated 2,3-dihydrobenzo­heteroles, 2,3-dihydro­benzo­furans, 2,3-dihydro­benzo­thio­phenes, and indolines were readily synthesized from <i>ortho</i>-heterosubstituted bromobenzenes, 2-bromophenols, 2-bromo­benzene­thiols, and 2-bromo­anilines, respectively, in two steps: (1) γ-selective allylic substitution of 3-bromo-3,3-difluoro­propene with heteronucleophiles and (2) intramolecular radical cyclization of the resulting 3,3-difluoroallylic compounds

Unveiling Three-Dimensional Stacking Sequences of 1T Phase MoS₂ Monolayers by Electron Diffraction

The phase transition between semiconducting 1H to metallic 1T phases in monolayered transition metal dichalcogenides (TMDs) essentially involves three-dimensional (3D) structure changes of asymmetric relocations of S atoms at the top and bottom of the one-unit-cell crystals. Even though the phase transition has a profound influence on properties and applications of 2D TMDs, a viable approach to experimentally characterize the stacking sequences of the vertically asymmetrical 1T phase is still not available. Here, we report an electron diffraction method based on dynamic electron scattering to characterize the stacking sequences of 1T MoS₂ monolayers. This study provides an approach to unveil the 3D structure of 2D crystals and to explore the underlying mechanisms of semiconductor-to-metal transition of monolayer TMDs

Domino C–F Bond Activation of the CF₃ Group: Synthesis of Fluorinated Dibenzo[<i>a</i>,<i>c</i>][7]annulenes from 2‑(Trifluoromethyl)-1-alkenes and 2,2′-Diceriobiaryls

The construction of ring-fluorinated seven-membered carbocycles was readily achieved via the domino S_N2′-type/S_NV reaction between 2-(trifluoromethyl)-1-alkenes and 1,4-carbodianions. The S_N2′-type reaction of 2-(trifluoromethyl)-1-alkenes with 2,2′-diceriobiaryls generated the intermediary 1,1-difluoro-1-alkenes bearing a monoceriobiaryl moiety, which in turn underwent intramolecular S_NV reaction to afford fluorinated 5<i>H</i>-dibenzo­[<i>a</i>,<i>c</i>]­[7]­annulenes

Domino C–F Bond Activation of the CF₃ Group: Synthesis of Fluorinated Dibenzo[<i>a</i>,<i>c</i>][7]annulenes from 2‑(Trifluoromethyl)-1-alkenes and 2,2′-Diceriobiaryls

The construction of ring-fluorinated seven-membered carbocycles was readily achieved via the domino S_N2′-type/S_NV reaction between 2-(trifluoromethyl)-1-alkenes and 1,4-carbodianions. The S_N2′-type reaction of 2-(trifluoromethyl)-1-alkenes with 2,2′-diceriobiaryls generated the intermediary 1,1-difluoro-1-alkenes bearing a monoceriobiaryl moiety, which in turn underwent intramolecular S_NV reaction to afford fluorinated 5<i>H</i>-dibenzo­[<i>a</i>,<i>c</i>]­[7]­annulenes

Platform for Ring-Fluorinated Benzoheterole Derivatives: Palladium-Catalyzed Regioselective 1,1-Difluoroallylation and Heck Cyclization

The synthesis of difluoromethylene-containing heterocycles was achieved via the palladium-catalyzed 1,1-difluoroallylation of heteronucleophiles followed by intramolecular Heck reaction. The allylic substitution of 3-bromo-3,3-difluoropropene was regioselectively accomplished by heteronucleophiles without rearrangement to give the corresponding 1,1-difluoroallylated compounds whose Heck cyclization proceeded in a 5-<i>exo</i> manner to afford ring-difluorinated indolines and dihydrobenzofurans. Their defluorinative allylic substitution further provided 2-fluoroindoles and 2-fluorobenzofurans

Image1_Hearing loss in mice with disruption of auditory epithelial patterning in the cochlea.TIF

In the cochlear auditory epithelia, sensory hair and supporting cells are arranged in a checkerboard-like mosaic pattern, which is conserved across a wide range of species. The cell adhesion molecules nectin-1 and nectin-3 are required for this pattern formation. The checkerboard-like pattern is thought to be necessary for auditory function, but has never been examined. Here, we showed the significance of checkerboard-like cellular pattern in the survival and function of sensory hair cells in the cochlear auditory epithelia of nectin-3 knockout (KO) mice. Nectin-3 KO mice showed progressive hearing loss associated with degeneration of aberrantly attached hair cells via apoptosis. Apoptotic hair cell death was due to the disorganization of tight junctions between the hair cells. Our study revealed that the checkerboard-like cellular pattern in the auditory epithelium provides a structural basis for ensuring the survival of cochlear hair cells and hearing function.</p