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Chemistry, An Asian Journal

Mahdiyeh-Sadat Hosseini, Majid Masteri-Farahani
New magnetically recoverable solid acid catalysts for acid-catalyzed reactions were designed via the surface chemical functionalization of silica-coated magnetite nanoparticles (SCMNPs) with sulfonic acid groups. First, the SCMNPs were covalently functionalized with 3-aminopropyl groups to achieve Amp-SCMNPs. Then, reaction of the Amp-SCMNPs with 1,4-butane sultone followed by acidification with phosphotungstic acid (HPW) or diluted sulfuric acid produced magnetically recoverable solid acid catalysts, HPW-ampsul-SCMNPs and H-ampsul-SCMNPs, respectively...
February 20, 2019: Chemistry, An Asian Journal
Freddy Marpaung, Konstantin Konstantinov, Yusuke Yamauchi, Md Shahriar A Hossain, Jongbeom Na, Jeonghun Kim
Metal-organic frameworks (MOFs)-derived nanoporous carbon materials have received significant interest due to their advantages of controllable porosity, good thermal/chemical stability, high electrical conductivity, catalytic activity, easy modification with other elements and materials, etc. Thus, MOF-derived carbons have been used in numerous applications such as environment, energy storage systems (i.e., batteries, supercapacitors), catalysts, etc. Until now, many strategies have been developed in order to enhance the properties and performances of MOF-derived carbons...
February 20, 2019: Chemistry, An Asian Journal
Yongju Kim, Xin Liu, Huichang Li, Myongsoo Lee
Here we report fluorescence turn-on synthetic lipid rafts by self-assembly of a cationic distyrylanthracene derivative on a negatively-charged sheet in an aqueous solution. First, the negatively-charged 2D membrane structure is formed by lateral associations of aromatic rods with carboxylate groups. Then, the synthetic rafts are provided floating on the surface of the negatively-charged sheets through electrostatic interactions. The fluorescence of the synthetic rafts is turned on due to the aggregation of positively-charged AIE dye on the sheets, facilitating monitoring for the formation of rafts...
February 19, 2019: Chemistry, An Asian Journal
Dennis K P Ng, Wen-Jing Shi, Jian-Yong Liu, Pui-Chi Lo
By using copper-promoted alkyne-azide cycloaddition reaction, two boron dipyrromethene (BODIPY) derivatives bearing a bis(1,2,3-triazole)amino receptor at the meso position were prepared and characterized. For the analogue with two terminal triethylene glycol chains, the fluorescence emission at 509 nm responded selectively toward Hg2+ ion, which greatly increased the fluorescence quantum yield from 0.003 to 0.25 as a result of inhibition of the photoinduced electron transfer (PET) process. By introducing two additional rhodamine moieties at the termini, the resulting conjugate could also detect Hg2+ ion in a highly selective manner...
February 18, 2019: Chemistry, An Asian Journal
Qiang Chen, Di Wang, Martin Baumgarten, Dieter Schollmeyer, Klaus Müllen, Akimitsu Narita
Dibenzo[hi,st]ovalene (DBOV) is a nanographene with a combination of zigzag and armchair edges, consisting of 38 sp2 carbons. Excellent optical properties with strong red emission have been demonstrated. Here we report the regioselective bromination of DBOV bearing two mesityl groups (DBOV-Mes) by treatment with N-bromosuccinimide (NBS) under a mild condition. The dibrominated DBOV was further subjected to transition-metal-catalyzed cross-coupling reactions, i.e. Suzuki and Sonogashira coupling, demonstrating the edge-decoration of DBOV with different functional groups...
February 18, 2019: Chemistry, An Asian Journal
Shouxiang Zhang, Mengjie Liu, Lewis Yi Fong Tan, Quentin Hong, Ze Liang Pow, Tze Cin Owyong, Siyang Ding, Wallace Wing Ho Wong, Yuning Hong
Collapse of the protein homeostasis (proteostasis) can lead to accumulation and aggregation of unfolded proteins, which has been found to associate with a number of disease conditions including neurodegenerative diseases, diabetes and inflammation. Here we report a maleimide-functionalized tetraphenylethene (TPE)-derivatized fluorescent probe, TPE-NMI, which shows fluorescence turn-on property upon reacting with unfolded proteins in vitro and in live cells under proteostatic stress conditions. The level of unfolded proteins can be measured by using flow cytometry and visualized with confocal microscopy...
February 15, 2019: Chemistry, An Asian Journal
Thomas B J Hall, Bryce R Hoggard, Christopher B Larsen, Nigel T Lucas
Hexa-peri-hexabenzocoronenes with a bay-fused five-membered ring are synthesized from fluorenyl precursors. The key oxidative cyclodehydrogenation step is accompanied by regioselective chlorination that is enhanced by methylation at the cyclopenta-ring or increased reaction concentration. The CpHBC products undergo mild electrophilic aromatic bromination, without catalyst, to afford adducts suitable for π-extension by cross-coupling.
February 14, 2019: Chemistry, An Asian Journal
Sheng Xie, Sesha Manuguri, Olof Ramström, Mingdi Yan
The fluorescence properties of AIE-active N-amidinated fluoroquinolones, efficiently obtained by a perfluoroaryl azide-aldehyde-amine reaction, have been studied. The fluorophores were discovered to elicit a highly sensitive fluorescence quenching response towards guest molecules with hydrogen-bond-donating ability. This effect was evaluated in a range of protic/aprotic solvents with different H-bonding capabilities, and also in aqueous media. The influence of acid/base was furthermore addressed. The hydrogen-bonding interactions were studied by IR, NMR, UV-Vis and time-resolved fluorescence decay, revealing their roles in quenching of the fluorescence emission...
February 14, 2019: Chemistry, An Asian Journal
Sambasivarao Kotha, Milind Meshram, Nageswara Rao Panguluri, Vrajesh R Shah, Saidulu Todeti, Mukesh E Shirbhate
In this report, we summarize various synthetic approaches to star-shaped molecules. To design these highly functionalized molecules, several simple building blocks are assembled via trimerization protocols starting with commercially available starting materials. Later on, these building blocks were synthetically manipulated to generate extended star-shaped molecules. We also presented the syntheses of star-shaped molecules having 2,4,6-trisubstituted-1,3,5-triazine or 1,3,5-trisubstituted benzene rings as a central core and diverse substituted styrene, phenyl, fluorene derivatives at the periphery renders the extended conjugation...
February 14, 2019: Chemistry, An Asian Journal
Xinzhang Lin, Chao Liu, Xuemei Fu, Jiahui Huang
Metal ions have important impact on the precise controlling synthesis and atomic structural arrangement of noble metal nanoclusters. In this work, it is the first time to reveal metal ion effect on the isomer generation of metal nanoclusters. Compared with the previous Ag23 nanoclusters with two FCC unit cells twisting 27°, the Ag23 isomer had a higher-symmetry structure with two FCC unit cells almost overlapping. In addition, Uv-vis absorption spectrum of the isomer showed a slight redshift of ~14 nm. The redshift might be because of the modulation of electronic structure which derived from fine-tuned crystal structure...
February 13, 2019: Chemistry, An Asian Journal
Bo Jiang, Tian-Shu Zhang, Qi Zhao, Wen-Juan Hao, Shu-Jiang Tu
A new Cu-catalyzed [4 + 1] annulation of N-aryl-1,2,3,4-tetrahydroisoquinolines (N-aryl THIQs) with α-diazoketones has been established under oxidative conditions, leading to the construction of a series of indolo[2,1-a]isoquinolines with generally good yields. The reaction enables dediazotized dicarbonylation of α-diazoketones, making direct C(sp3)/C(sp2)-H bond bifunctionalization to access tetracyclic aza-heterocyclic skeletons.
February 13, 2019: Chemistry, An Asian Journal
Yaozu Zhang, Dongsheng Sun, Jixing Gao, Xiuni Hua, Xiaogang Chen, Guangquan Mei, Weiqiang Liao
Piezoelectric materials are a class of important functional materials applied in high-voltage sources, sensors, vibration reducer, actuators, motors, and so on. Herein, [(CH3)3S]3[Bi2Br9](1) is a brilliant semiconducting organic-inorganic hybrid perovskite-type non-ferroelectric piezoelectric with excellent piezoelectricity. Strikingly, the value of piezoelectric coefficient d33 is estimated about 18 pC/N. Such a large piezoelectric coefficient in non-ferroelectric piezoelectricity has been scarcely reported, comparable with those of typically one-composition non-ferroelectric piezoelectricity such as ZnO (3 pC/N) and much greater than those of most known typical materials...
February 12, 2019: Chemistry, An Asian Journal
Tanwistha Ghosh, Shinji Nagasawa, Neethi Raveendran, Vibhu Darshan, Akinori Saeki, Vijayakumar C Nair
Precise control over the supramolecular organization of organic semiconducting materials guiding to exclusive face-on or edge-on orientation is a challenging task. In the present work, we study the preferential packing of thiophene oligomers induced through rational molecular designing and self-assembly. The acceptor-donor-acceptor type oligomers having 2-(1,1-dicyano-methylene)rhodanine as acceptor (OT1) favored a face-on packing, while that of functionalized with N-octyl rhodanine (OT2) preferred an edge-on packing as evident from 2D-grazing incidence angle X-ray diffraction, tapping-mode atomic force microscopy (AFM) and Raman spectroscopy analyses...
February 12, 2019: Chemistry, An Asian Journal
Mahbod Morshedi, Stephanie A Boer, Michael Thomas, Nicholas G White
Despite their ready availability, O-H groups have received relatively little attention as anion recognition motifs. Here, we report two simple hydroxy-containing anion receptors that are prepared in two facile steps followed by anion exchange, without the need for chromatographic purification at any stage. These receptors contain a pyridinium bis(amide) motif as well as hydroxyphenyl groups, and bind mono- and divalent anions in 9:1 CD3 CN:D2 O, showing a selectivity preference for sulfate. Notably, a "model" receptor that does not contain hydroxy groups shows only very weak sulfate binding in this competitive solvent mixture...
February 12, 2019: Chemistry, An Asian Journal
Holger Helten
The doping of pi-conjugated organic compounds with trivalent boron atoms produces materials with intriguing properties and functions that result from the interaction of the pi-electron system with the vacant p orbital on boron. This offers unique opportunities in various applications such as organic (opto)electronics, biomedical imaging, and sensors for physiologically relevant anions or amines, as demonstrated by numerous examples on the molecular scale. Recently, the B-doping strategy has been expanded to polymer chemistry with a view to benefit from the best of both worlds...
February 7, 2019: Chemistry, An Asian Journal
Min Wang, Yaru Li, Chuanqi Feng, Guanyu Zhao, Zhong-Sheng Wang
Iron nickel cobalt selenides are synthesized through a one-step hydrothermal method. The quaternary Fe0.37Ni0.17Co0.36Se demonstrates multifunctionality, possessing high electrocatalytic activity for quasi-solid-state dye-sensitized solar cells with power conversion efficiency of 8.42%, hydrogen evolution reaction, oxygen evolution reaction, and water splitting. The output electric power from the tandem quasi-solid-state dye-sensitized solar cells under one-sun illumination is sufficient to split water, exhibiting solar-to-hydrogen conversion efficiency of 5...
February 6, 2019: Chemistry, An Asian Journal
Xiang-Lan Chen, Jia-Wei Huang, Yi-Chen Huang, Jie Du, Yu-Fei Jiang, Yue Zhao, Hai-Bin Zhu, Xian-Lan Chen
Fe-Co-N-C electrocatalysts have proven superior to their counterparts (e.g. Fe-N-C or Co-N-C) for the oxygen reduction reaction (ORR). Herein, we report on a unique strategy to make Fe-Co-N-C-x (x refers to the pyrolysis temperature) electrocatalysts which involves anion-exchange of [Fe(CN)6]3- into a cationic Co(II)-based metal-organic framework precursor prior to heat treatment. Fe-Co-N-C-900 exhibits the optimal ORR catalytic performance in alkaline electrolyte with the comparable onset potential (Eonset: 0...
February 6, 2019: Chemistry, An Asian Journal
Fang Wang, Daniel Song, Diane A Dickie, Cassandra L Fraser
Emissive β-diketones (bdks) and difluoroboron complexes (BF2 bdks) show multi-stimuli responsive luminescence in both solution and the solid state. A series of bdk ligands and boron coordinated dyes were synthesized with different cyclic amine substituents in the 4-position to explore ring size effects on various luminescent properties, including solvatochromism, viscochromism, aggregation-induced emission (AIE), mechanochromic luminescence (ML) and halochromism. Red-shifted absorption and emission were observed in CH2 Cl2 for both bdk ligands and boron dyes with increasing substituent ring size...
February 5, 2019: Chemistry, An Asian Journal
Akassong Dominique Dinga Wonanke, Jayne L Gulbrandsen, Chris M Fitchett, Deborah Lee Crittenden
Photochemical oxidative cyclodehydrogenation reactions are a versatile class of aromatic ring-forming reactions. They can be used to form a diverse range of extended polyaromatic systems by fusing existing ring substituents, because they are tolerant to functional group substitution and heteroatom inclusion. However, despite their undoubted synthetic utility, there are no existing models - computational or heuristic - that predict the outcome of photocyclisation reactions across all possible classes of reactants...
February 4, 2019: Chemistry, An Asian Journal
Hongming He, Qian-Qian Zhu, Chuanqi Zhang, Ying Yan, Jing Yuan, Jing Chen, Cheng-Peng Li, Miao Du
It is a great challenge to rationally integrate multiple reactive sites into a composite material with confined nano-space, which can be applied as a nanoreactor to facilitate targeting catalytic reaction. In this work, an ionic metalloporphyrin has been in situ encapsulated into ZIF-8 for the solvent-free synthesis of cyclic carbonates from CO2 and epoxides without any co-catalyst under 1 atm CO2.
February 4, 2019: Chemistry, An Asian Journal
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