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Chemistry, An Asian Journal

Tao Tu, Qinyue Deng, Yang Zhang, Haibo Zhu
A series of robust N-heterocyclic carbene palladacycles have been successfully developed, which exhibited high catalytic activity and selectivity toward the challenging amination of N-heteroaryl chlorides. Diverse primary and secondary amines are fully compatible with our new developed catalytic system. Remarkably, no double amination products could be detected when primary amines were utilized in our catalytic transformation. Furthermore, the protocol has been successfully extended to synthesize Rosiglitazone, a clinical drug for diabetes mellitus, highlighting its potential pharmaceutical feasibility...
July 18, 2017: Chemistry, An Asian Journal
Alessandro Palmioli, Carlotta Cairamelli, Renata Tisi, Michela Spinelli, Gaia De Sanctis, Elena Sacco, Cristina Airoldi
Recent epidemiological studies demonstrate that consumption of healthy foods, especially rich in polyphenols content, might reduce the incidence of cancer and degenerative diseases. In particular, chlorogenic acids (CGAs) occur ubiquitously in food, representing the most abundant polyphenols in the human diet. A number of CGA beneficial biological effects, including anti-inflammatory activity, anti-carcinogenic activity and protection against neurodegenerative diseases have been reported. However, the molecular mechanisms at the basis of these biological activities have not yet been investigated in depth...
July 18, 2017: Chemistry, An Asian Journal
Bahadur Sk, Pilendra Thakre, Raghuvir Singh Tomar, Abhijit Patra
A versatile fluorescent probe, PITE, based on alkyl substituted pyridoindole (PI) and tetraphenylethylene (TE) exhibiting facile pH-induced fluorescence switching in solution, nanoparticles and solid state is presented. Strong fluorescence in the solid state besides solution and aggregated state allow sensing of toxic acid vapor. Fluorescence "off-on" switching of PITE by exposing to trifluoracetic acid and triethylamine vapor is visualized through naked eyes. A unified picture of switchable fluorescence of PITE is obtained by comprehensive spectroscopic investigations coupled with quantum mechanical calculations...
July 18, 2017: Chemistry, An Asian Journal
Juri Takeshita, Yuki Hasegawa, Kazushige Yanai, Ayumu Yamamoto, Ayumi Ishii, Miki Hasegawa, Masamichi Yamanaka
The development of an effective adsorbent for cleansing polluted water is required for environmental purification. In this respect, a supramolecular hydrogel constructed by the self-assembly of small molecules could be a strong candidate. Adsorption experiments of organic dyes were performed using supramolecular hydrogels of amphiphilic tris-urea 1. Cationic organic dyes were adsorbed efficiently; indeed, the adsorption of methylene blue was as high as 4.19 mol equivalents relative to 1. Two luminescence peaks were observed in the rhodamine 6G-adsorbed supramolecular hydrogels, and their ratios varied with the amount of dye adsorbed...
July 12, 2017: Chemistry, An Asian Journal
Wan-Yin Fang, Jing Leng, Hua-Li Qin
A one-pot Pd-catalyzed carbonylation of phenols to their corresponding arylcarboxylic acids and esters through the insertion of carbon monoxide is developed. This protocol provides a mild condition for direct synthesis of arylcarboxylic acids and esters from inexpensive and abundant starting materials of phenols, SO2F2 and CO. This method was found to tolerate a broad of functional groups and was also applicable for modification of complicated natural products.
July 12, 2017: Chemistry, An Asian Journal
Yunpeng Huang, Fen Cui, Yan Zhao, Jian Bao, Jiabiao Lian, Yuanguo Xu, Tianxi Liu, Hua-Ming Li
Exploring non-precious metal-based ORR electrocatalysts featuring high efficiency, low cost and environmental friendliness is of great importance for the broad applications of fuel cells and metal-air batteries. In this work, one-dimensional (1D) SnO2 nanotubes (SNT) deposited with ultra-thin NiCo2O4 nanosheets was successfully fabricated through a productive electrospinning technique followed by sintering and low-temperature co-precipitation strategy. This hierarchically engineered architecture has ultrathin NiCo2O4 nanosheets uniformly and fully erecting on both walls of tubular SNT, which manifests improved electrochemical activity as oxygen reduction reaction (ORR) catalyst in terms of positive onset potential and high current density, as well as superior tolerance to crossover effects and long-term durability with respect to the commercial Pt/C catalyst...
July 12, 2017: Chemistry, An Asian Journal
Hong Yan, Xiang Li, Yongheng Yin, Changsheng Lu
TPE-carborane hybrids are constructed, and the impact of carborane substituents on the AIE characteristics of TPE-cores has been investigated. When altering the 2-R-group on the carborane unit by -H, -CH3 or phenyl group, the luminescent quantum yield of the corresponding TPE derivatives can be manipulated from 0.18 to 0.63 in solid state. The emission color exhibits an obvious shift by 100 nm (from blue to yellow).
July 11, 2017: Chemistry, An Asian Journal
Wei Su, Kui Zhou, Fanglin Cai, Cheng Chen, Bibimaryam Mousavi, Somboon Chaemchuen, Francis Verpoort
: A dinuclear ruthenium complex [RuII(NCNHCO)(pic)2]22+ (2) was firstly prepared and characterized spectroscopically and electrochemically. Instead of the conventional ligand exchange, complex 2 dissociates in-situ to afford two single-site Ru aqua complexes, [RuII(OH2)(NCNHCO)(pic)2]+, which mediates water oxidation through proton-coupled electron transfer events. In electrokinetic studies, complex 2 demonstrated a TOF of 150.3 s-1 comparable to those state-of-the-art catalysts at neutral conditions. TONs of 2173 and 217 were attained in chemical and photochemical water oxidation when 2 was used as a catalyst, exhibiting good stability...
July 11, 2017: Chemistry, An Asian Journal
Hee-Jun Park, Si Hyun Han, Jun Yeob Lee
D-A-D type thermally activated delayed fluorescence (TADF) emitters, 5,5'-bis(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)-2,2'-bipyrimidine (Ac-bpm) and 5,5'-bis(4-(10H-phenoxazin-10-yl)phenyl)-2,2'-bipyrimidine (Px-bpm), based on 2,2'-bipyrimidine accepting unit were developed and their TADF devices were fabricated. The orthogonal geometry between the donor unit and the 2,2'-bipyrimidine accepting core facilitated a HOMO/LUMO spatial separation, thus realizing thermally activated delayed fluorescence. They exhibited electroluminescence ranging from green to yellow, depending on the donor unit, with a maximum external quantum efficiencies of up to 17...
July 11, 2017: Chemistry, An Asian Journal
Shijun Zhu, Yikang Wu
The relative and absolute configuration of neomaclafungins were impossible to establish by spectroscopic analyses alone because of the lack of exploitable 1H-1H couplings and nOe's between the upper and the lower subunits. This very difficult task now is finally completed by an enantioselective total synthesis of neomaclafungin A (revised) and its diastereomer (reported). The results also provided a key reference for the complete structures for other neomaclafungins and the long-known closely related natural product maclafungin...
July 10, 2017: Chemistry, An Asian Journal
Yanshu Shi, Xiaoran Deng, Shouxin Bao, Bei Liu, Bin Liu, Ping'an Ma, Ziyong Cheng, Maolin Pang, Jun Lin
Size and shape controlled growth of nanoscale microporous organic polymers (MOPs) is a big challenge scientists confronted with, meanwhile, rendering these materials for in vivo biomedical applications is still scarce. In this study, monodispersed nano metalation covalent organic polymers (MCOP, M = Fe, Gd) with sizes around 120 nm were prepared by a self-templated two-step solution-phase synthesis method. The metal ions (Fe3+) played important roles in miniature the particle size and functionalization of the products during reaction with p-phenylenediamine (Pa), and then the resultant Fe-Pa complex was used as a template for the subsequent formation of MCOP following the Schiff base reaction with 1,3,5-triformylphloroglucinol (Tp)...
July 10, 2017: Chemistry, An Asian Journal
Yi-Ling Yan, Jiun-Rung Guo, Chien-Fu Liang
Dysprosium(III) trifluoromethanesulfonate-catalyzed per-O-acetylation and regioselective anomeric de-O-acetylation of carbohydrates can be tuned by adjusting the reaction medium. In this study, per-O-acetylation of unprotected sugars by using a near stoichiometric amount of acetic anhydride under solvent-free conditions resulted in the exclusive formation of acetylated saccharides as anomeric mixtures, whereas anomeric de-O-acetylation in methanol resulted in a moderate to excellent yield. Reactions with various unprotected monosaccharide or disaccharide followed by a semi-one-pot sequential conversion into the corresponding acetylated glycosyl hemiacetal also resulted in high yields...
July 8, 2017: Chemistry, An Asian Journal
Jie Hao, Yuxia Gao, Ying Li, Qiang Yan, Jun Hu, Yong Ju
Thermoresponsive water-soluble polymers are of great importance since they typically show a lower critical solution temperature (LCST) in aqueous media. In this research, the LCST change in broad temperature ranges of copolymers composed of natural glycyrrhetinic acid (GA)-based methacrylate and N,N'-dimethylacrylamides (DMAs) was investigated as a function of the concentration and the content of GA pendants. By complexation of GA pendants with β-cyclodextrin (β-CD), a side-chain polypseudorotaxane was obtained, which exhibited a significant increase in the LCST of copolymers...
July 7, 2017: Chemistry, An Asian Journal
Jinming Zeng, Xiaoyuan Zhang, Xiaoting Zhu, Ping Liu
A series of star-shaped conjugated oligomers, 1,3,5-tri(2'-thienyl) benzene (3TB), 1,3,5-tri(3',4'-ethylenedioxythienyl) benzene (3EB), 1,3,5-tri[5',2"-(3",4"-ethylenedioxythienyl)-2'-thienyl] benzene (3ETB), and 1,3,5-tri[5',2"-(3",4"-ethylenedi- oxythienyl)-2'-thienyl]-4-(3',4'-ethylenedioxythienyl)benzene (3TB-4EDOT), were synthesized. The star-shaped polymer, poly(1, 3,5-tri[5',2"-(3",4"-ethylenedioxythineyl)-2'-thienyl]benzene) (P3ETB), was also prepared. The electrochemical and electrochromic properties of these conjugated oligomers and polymer were investigated...
July 5, 2017: Chemistry, An Asian Journal
Renlu Han, Junhui Shi, Zongjun Liu, Hao Wang, You Wang
A novel photodynamic therapy nanoplatform based on mesoporous silica-coated upconverting nanoparticles (UCNP) with electrostatic-driven ultrafast photosensitizer (PS) loading and 808 nm near infrared (NIR) light triggering capabilities has been fabricated. By positively charging inner channels of the mesoporous silica shell with amino groups, a quantitative dosage of negatively charged PS, exemplified with Rose Bengal (RB) molecules, can be uploaded in 2 min. In addition, the electrostatic-driven technique simultaneously provides the platform with both excellent PS dispersity and leak-proof properties due to the repulsion between the same charged molecules and the electrostatic attraction between different charged PS and silica channel wall respectively...
July 3, 2017: Chemistry, An Asian Journal
Subashchandrabose Thoka, Mahesh Madasu, Chi-Fu Hsia, Shu-Ya Liu, Michael Hsuan-Yi Huang
Copper nanocubes with average sizes of 82, 95, and 108 nm have been synthesized in an aqueous mixture of cetyltrimethylammonium chloride (CTAC) surfactant, copper acetate, and sodium ascorbate reductant heated at 100 ºC for 40 min. Copper nanowires with an average length of 25 m can also be prepared this way by simply increasing the volume of sodium ascorbate introduced. Small shifts in the plasmonic absorption band positions with tunable particle sizes have been observed. The copper nanocubes were employed to catalyze hydroboration of phenylacetylene and various substituted aryl alkynes with 100% (E)-product selectivity and 82-95% product yields...
July 3, 2017: Chemistry, An Asian Journal
Amjad Islam, Dongdong Zhang, Ruixiang Peng, Rongjuan Yang, Ling Hong, Wei Song, Qiang Wei, Lian Duan, Ziyi Ge
Blue organic light-emitting diodes (OLEDs) are necessary for flat-panel display technologies and lighting application. To make more energy saving, low cost and long-lasting OLEDs, efficient materials as well as simple structured devices are highly demanded. However, a very limited number of blue OLEDs achieving high stability and color purity are reported. Herein, three new sky-blue emitters, TPEI, TPEMeOPhI and 3TPEI, with the combination of imidazole and tetraphenylethene groups have been developed. High photoluminescence quantum yields are obtained for these materials...
July 3, 2017: Chemistry, An Asian Journal
Jingyang Niu, Ling Yang, Jipeng Guo, Li Li, Qisen Liu, Pengtao Ma, Jingping Wang
A flexible one-pot strategy exploiting pyramidal SeIV heteroatom is employed for the assembly of praseodymium-containing gly-decorated polyoxotungstate [{Pr3(H2O)10[Se2W22O76(gly)2]}2(Se2W7O30H2)]18- (1a), which is constructed from one {Se2W7O30H2} unit and two identical {Pr3(H2O)10[Se2W22O76(gly)2]} units. Furthermore, the catalytic performance of Cs2Na4H12[{Pr3(H2O)10[Se2W22O76(gly)2]}2 (Se2W7O30H2)]∙25H2O (1) for alkenes epoxidation with hydrogen peroxide was investigated under mild reaction conditions...
July 1, 2017: Chemistry, An Asian Journal
Seon Kyu Mun, Sangmin Lee, Dong Young Kim, Seong Jung Kwon
Collisions of silver (Ag) nanoparticles (NPs) with a more electrocatalytic gold (Au) or platinum (Pt) ultramicroelectrode (UME) surface have been observed using an electrochemical method. Depending on the applied potential to the UME, the current response of Ag NPs collision onto the UME resulted in various shape changes. A staircase decrease, a blip decrease, and a blip increase of the hydrazine oxidation current were obtained at an applied potential of 0.33 V, 0.80 V, and 1.3 V, respectively. Different behaviors of Ag NP collision on the UME surface were suggested for each shape of current response...
June 29, 2017: Chemistry, An Asian Journal
Pengquan Chen, Chuanle Zhu, Rui Zhu, Wanqing Wu, Huanfeng Jiang
A catalyst-free oxidative radical sulfonylation of haloalkynes with sulfonyl hydrazides is reported. It represents an example of C(sp)-S bond formation using sulfonyl hydrazides as sulfonyl radical sources. Various alkynyl sulfones were synthesized in moderate to good yields. Having MnO2 as the oxidant is very critical for this transformation. Remarkably, the self-coupling reaction of haloalkynes through C(sp)-C(sp) bond formation is significantly inhibited under the standard reaction conditions.
June 29, 2017: Chemistry, An Asian Journal
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