Thienoisatin Oligomers as N-Type Molecular Semiconductors

Organic field effect transistors (OFETs) offer many advantages compared to traditional inorganic transistors, such as flexibility and solution processability. In this study we design and synthesize two thienoisatin-based organic semiconducting small molecules, then investigate their electronic properties in n-type OFETs. To introduce n-type charge transport, electron-withdrawing dicarbonitrile moieties were installed on thienoisoindigo and bis-thienoisatin molecules, which led to a quinoidal conjugation on thienoisoindigo, while maintaining an aromatic conjugation on the bis-thienoisatin. Following the syntheses, the molecules were characterized to determine highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels via cyclic voltammetry, as well as any potential radical properties

Bilateral Fronto-Parietal Integrity in Young Chronic Cigarette Smokers: A Diffusion Tensor Imaging Study

Cigarette smoking continues to be the leading cause of preventable morbidity and mortality in China and other countries. Previous studies have demonstrated gray matter loss in chronic smokers. However, only a few studies assessed the changes of white matter integrity in this group. Based on those previous reports of alterations in white matter integrity in smokers, the aim of this study was to examine the alteration of white matter integrity in a large, well-matched sample of chronic smokers and non-smokers.Using in vivo diffusion tensor imaging (DTI) to measure the differences of whole-brain white matter integrity between 44 chronic smoking subjects (mean age, 28.0±5.6 years) and 44 healthy age- and sex-matched comparison non-smoking volunteers (mean age, 26.3±5.8 years). DTI was performed on a 3-Tesla Siemens scanner (Allegra; Siemens Medical System). The data revealed that smokers had higher fractional anisotropy (FA) than healthy non-smokers in almost symmetrically bilateral fronto-parietal tracts consisting of a major white matter pathway, the superior longitudinal fasciculus (SLF).We found the almost symmetrically bilateral fronto-parietal whiter matter changes in a relatively large sample of chronic smokers. These findings support the hypothesis that chronic cigarette smoking involves alterations of bilateral fronto-parietal connectivity

\u3ci\u3en\u3c/i\u3e-Type Charge Transport in Heavily \u3ci\u3ep\u3c/i\u3e-Doped Polymers

It is commonly assumed that charge-carrier transport in doped π-conjugated polymers is dominated by one type of charge carrier, either holes or electrons, as determined by the chemistry of the dopant. Here, through Seebeck coefficient and Hall effect measurements, we show that mobile electrons contribute substantially to charge-carrier transport in π-conjugated polymers that are heavily p-doped with strong electron acceptors. Specifically, the Seebeck coefficient of several p-doped polymers changes sign from positive to negative as the concentration of the oxidizing agents FeCl3 or NOBF4 increase, and Hall effect measurements for the same p-doped polymers reveal that electrons become the dominant delocalized charge carriers. Ultraviolet and inverse photoelectron spectroscopy measurements show that doping with oxidizing agents results in elimination of the transport gap at high doping concentrations. This approach of heavy p-type doping is demonstrated to provide a promising route to high-performance n-type organic thermoelectric materials

Acceptor Moieties with Extended Conjugation for Semiconducting Polymers

The field of semiconducting conjugated polymers has grown tremendously over the past few decades with innovations expanding the use of conjugated polymers into several devices such as transistors, light emitting diodes, and biocompatible electronics. For transistor devices, charge carrier mobility has rivaled the performance of amorphous silicon. The intrinsic properties of organic materials make them extremely attractive for further development and application. Organic materials are synonymous with terms such as lightweight, robust, flexible, and stretchable. A major advantage of conjugated polymers is their ability to be rendered solution processable with the alluring potential for large-area green manufacturing of electronic devices. However, these properties often fall short of their potential. Often strain engineering is often employed for favorable mechanical properties of polymer thin films. Incorporation of acceptor-acceptor (A-A) type moieties into donor-acceptor (D-A) type conjugated polymers becomes a new strategy to tune their electronic properties. In this work, we first demonstrate an efficient convergent route to prepare isoindigo-based A-A type building blocks - bis-isoindigos - via the palladium-catalyzed oxidative coupling. Bis-isoindigo-based polymers show high planarity and delocalized frontier molecular orbitals with lowered LUMO and intact HOMO energy levels, in comparison with their corresponding mono-isoindigo counterparts. Moreover, fluorine substitution on donors only lowers HOMO levels of Bis-IID polymers. This study asserts that the D-A-A strategy is effective in selectively tuning FMO energy levels of conjugated polymers, complementary to the D-D-A approach for the HOMO energy level tuning. Finally, we investigated the effect ofisomer structure has on the properties of conjugation polymers utilizing diazines to decouple the effects of spatial arrangement from heteroatom placement. These studies highlight the significant impact of side-chain sequence regioisomerism on aggregation behaviors, morphologies, and subsequently charge transport properties of donor-acceptor type conjugated polymers

Zhitong Jiangu decoction mitigates osteoarthritis in rabbits via regulation of NF-κB signaling pathway

Purpose: To investigate the effect of Zhitong Jiangu decoction (ZJD) on osteoarthritis rabbits, and the mechanism of action involved. Methods: Chondrocytes were obtained from the knees of osteoarthritic rabbits. These chondrocytes were randomly assigned to 7 groups: sham, 5, 10 and 20 % normal serum groups; 5 % ZJD, 10 % ZJD and 20 % ZJD groups. The gross and histopathological features of the rabbit cartilage were examined by microscopy. Each group was treated with a different concentration of rabbit normal serum or rabbit drug-containing serum. The protective effect of different concentrations of ZJD on the cells were determined. Cell proliferation and concentrations of IL-1 and MMP-3 were determined using cell counting kit (CCK) 8 and enzyme-linked immunosorbent assay (ELISA), respectively. The mRNA and protein expressions of inhibitor of nuclear factor-κB kinase α (IKK-α) and nuclear factor kappa B p65 (NF- κB p65) were determined by quantitative reverse transcription polymerase chain reaction (qRT- PCR) and immunoblotting, as appropriate. Results: Gross and histopathological examinations of rabbit cartilage showed that osteoarthritis was successfully established in rabbit knee joint. Cell proliferation significantly and time- and concentration-dependently increased in drug-containing serum groups, relative to sham and normal serum-containing groups. However, expressions of NF-κB p65, IL-1, MMP-3 and IKK-α were markedly and time- and concentration-dependently reduced in drug-containing serum groups, relative to sham and normal serum-containing groups (p < 0.05). Conclusion: These results indicate that ZJD mitigates osteoarthritis in rabbits via regulation of NF-κB signaling pathway. Thus, it can potentially be developed for the management of osteoarthritis

Catalytic Azoarene Synthesis from Aryl Azides Enabled by a Dinuclear Ni Complex

Azoarenes are valuable chromophores that have been extensively incorporated as photoswitchable elements in molecular machines and biologically active compounds. Here, we report a catalytic nitrene dimerization reaction that provides access to structurally and electronically diverse azoarenes. The reaction utilizes aryl azides as nitrene precursors and generates only gaseous N₂ as a byproduct. By circumventing the use of a stoichiometric redox reagent, a broad range of organic functional groups are tolerated, and common byproducts of current methods are avoided. A catalyst featuring a NiNi bond is found to be uniquely effective relative to those containing only a single Ni center. The mechanistic origins of this nuclearity effect are described

Catalytic Azoarene Synthesis from Aryl Azides Enabled by a Dinuclear Ni Complex

Azoarenes are valuable chromophores that have been extensively incorporated as photoswitchable elements in molecular machines and biologically active compounds. Here, we report a catalytic nitrene dimerization reaction that provides access to structurally and electronically diverse azoarenes. The reaction utilizes aryl azides as nitrene precursors and generates only gaseous N₂ as a byproduct. By circumventing the use of a stoichiometric redox reagent, a broad range of organic functional groups are tolerated, and common byproducts of current methods are avoided. A catalyst featuring a NiNi bond is found to be uniquely effective relative to those containing only a single Ni center. The mechanistic origins of this nuclearity effect are described

Catalytic Azoarene Synthesis from Aryl Azides Enabled by a Dinuclear Ni Complex

Azoarenes are valuable chromophores that have been extensively incorporated as photoswitchable elements in molecular machines and biologically active compounds. Here, we report a catalytic nitrene dimerization reaction that provides access to structurally and electronically diverse azoarenes. The reaction utilizes aryl azides as nitrene precursors and generates only gaseous N₂ as a byproduct. By circumventing the use of a stoichiometric redox reagent, a broad range of organic functional groups are tolerated, and common byproducts of current methods are avoided. A catalyst featuring a NiNi bond is found to be uniquely effective relative to those containing only a single Ni center. The mechanistic origins of this nuclearity effect are described

Catalytic Azoarene Synthesis from Aryl Azides Enabled by a Dinuclear Ni Complex

Azoarenes are valuable chromophores that have been extensively incorporated as photoswitchable elements in molecular machines and biologically active compounds. Here, we report a catalytic nitrene dimerization reaction that provides access to structurally and electronically diverse azoarenes. The reaction utilizes aryl azides as nitrene precursors and generates only gaseous N₂ as a byproduct. By circumventing the use of a stoichiometric redox reagent, a broad range of organic functional groups are tolerated, and common byproducts of current methods are avoided. A catalyst featuring a NiNi bond is found to be uniquely effective relative to those containing only a single Ni center. The mechanistic origins of this nuclearity effect are described