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Organic synthesis

Ali Abdulkarim, Felix Hinkel, Daniel Jänsch, Jan Freudenberg, Florian E Golling, Klaus Müllen
Unsubstituted and structurally well-defined poly(para-phenylene) (PPP) has been long-desired as an organic semiconductor prototype of conjugated polymers. To date, several attempts to synthesize unsubstituted, pristine, high-molecular-weight PPP have failed. Here we solved this synthetic problem by a versatile precursor route. Suzuki polymerization of kinked disubstituted 1,4-dimethoxycyclohexadienylene monomers yielded a well-soluble, nonaromatic precursor polymer. Its solubility allowed processing by spin-coating into nanometer-thick films...
December 9, 2016: Journal of the American Chemical Society
Satobhisha Mukherjee, Biplab Maji, Adrian Tlahuext-Aca, Frank Glorius
Selective functionalization of ubiquitous C(sp(3))-H bonds using visible light is a highly challenging yet desirable goal in organic synthesis. The development of such processes relies on both rational design and serendipitous discoveries from innovative tools such as screening technologies. Applying a mechanism-based screening strategy, we herein report photoredox-mediated hydrogen atom transfer catalysis for the selective activation of otherwise unactivated C(sp(3))-H bonds, followed by their trifluoromethylthiolation, which has high potential as a late-stage functionalization tool...
December 9, 2016: Journal of the American Chemical Society
Dan Xiao, Guangwei Geng, Penglei Chen, Tiesheng Li, Minghua Liu
Silver halide-based structures have been attracting great interest as efficient visible-light-driven photocatalysts towards the photodegradation of organic pollutants, and those studies focusing on their morphology-dependent catalytic performances have received particular attention. While great advancements in this regard have been witnessed in the past few years with respect to AgCl- and AgBr-based photocatalysts, relevant explorations concerning AgI-based species are relatively rare, even though the excellent durability of AgI-based structures renders them attractive candidates for potential photocatalytic uses...
December 9, 2016: Physical Chemistry Chemical Physics: PCCP
Kateryna Bazaka, Ryan Destefani, Mohan V Jacob
This article presents low-temperature, one-step dry synthesis of optically transparent thermally-stable, biocompatible cis-β-ocimene-based thin films for applications as interlayer dielectric and encapsulating layer for flexible electronic devices, e.g. OLEDs. Morphological analysis of thin films shows uniform, very smooth (Rq < 1 nm) and defect-free moderately hydrophilic surfaces. The films are optically transparent, with a refractive index of ~1.58 at 600 nm, an optical band gap of ~2.85 eV, and dielectric constant of 3...
December 9, 2016: Scientific Reports
Donglei Wei, Fushun Liang
An organic photoredox catalytic one-pot protocol is developed for the highly stereoselective synthesis of (Z)-1,4-enediones. The reaction starts directly from alkyne precursors, using 4-(4-cyanophenyl)-2,6-diphenylpyrylium tetrafluoroborate (CN-TPT) as an efficient photosensitizer and dioxygen in the air as a green oxidant. A Csp-Csp oxidative coupling/[4 + 2] cyclization (with dioxygen)/fragmentive isomerization cascade mechanism was proposed. The predominant formation of (Z)-1,4-enediones is attributed to the efficient visible-light illumination from blue LEDs, along with possible energy transfer from the photosensitizer CN-TPT to the E-isomers...
November 18, 2016: Organic Letters
Andrea Ojeda-Porras, Diego Gamba-Sánchez
Amides are unquestionably one of the most important functional groups in organic chemistry because of their presence in numerous interesting molecules such as peptides, pharmaceutical agents, naturally occurring molecules, proteins and alkaloids, among others. This synopsis surveys the diverse recent approaches to amide synthesis from nonactivated carboxylic acids and derivatives as well as noncarboxylic compounds, highlighting the most innovative methodologies and those that are more eco-friendly compared to traditional methods while focusing on recent developments during the past two years...
December 2, 2016: Journal of Organic Chemistry
David Obermayer, Desiree Znidar, Gabriel Glotz, Alexander Stadler, Doris Dallinger, C Oliver Kappe
A newly designed robust and safe laboratory scale reactor for syntheses under sealed-vessel conditions at 250 °C maximum temperature and 20 bar maximum pressure is presented. The reactor employs conductive heating of a sealed glass vessel via a stainless steel heating jacket and implements both online temperature and pressure monitoring in addition to magnetic stirring. Reactions are performed in 10 mL borosilicate vials that are sealed with a silicone cap and Teflon septum and allow syntheses to be performed on a 2-6 mL scale...
December 2, 2016: Journal of Organic Chemistry
Devin B Granger, Yaochuan Mei, Karl J Thorley, Sean R Parkin, Oana D Jurchescu, John E Anthony
A new class of nitrogen-containing arene organic semiconductors incorporating fused indolizine units is described. This system, though having a zigzag shape, mimics the electronic properties of its linear analogue pentacene as a result of nitrogen lone pair incorporation into the π-electron system. Solubilizing trialkylsilylethynyl groups were employed to target crystal packing motifs appropriate for field-effect transistor devices. The triethylsilylethynyl derivative yielded hole mobilities of 0.1 cm(2) V(-1) s(-1) and on/off current ratios of 10(5)...
December 2, 2016: Organic Letters
Min Jae Sung, Seongwon Yoon, Soon-Ki Kwon, Yun-Hi Kim, Dae Sung Chung
A push-pull-type donor copolymer, named PP-TPD, was synthesized with the Suzuki coupling reaction using 6H-phenanthro[1,10,9,8-cdefg]carbazole (PCZ) as the donor unit and 1,3-bis(5-bromothiophen-2-yl)-5-octyl-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (TPD) as the acceptor unit. The synthesized PP-TPD was systematically investigated in terms of crystallinity and thermal, electrical, electrochemical, and optical properties. PP-TPD revealed green-selective absorption with a narrow full width at half-maximum of 138 nm...
November 16, 2016: ACS Applied Materials & Interfaces
Satyawan Nagane, Satishchandra Ogale
We report the synthesis of fully molecular ion (BF4(-))-based organic-inorganic hybrid perovskite CH3NH3Pb(BF4)3, which is a wide band gap semiconductor, and the same can be easily tuned toward the visible by the incorporation of bromide or iodide ions in the crystal framework simply by changing lead precursors. We have also successfully transformed the distorted 3D molecular-ion-induced perovskite to 2D (C4H9NH3)2Pb(BF4)4, (C4H9NH3)2PbBr(4-x)(BF4)x, and (C4H9NH3)2PbI(4-x)(BF4)x perovskites that exhibit the optical absorption over the UV to visible region...
November 17, 2016: Journal of Physical Chemistry Letters
Huajie Chen, Zhaoxia Liu, Zhiyuan Zhao, Liping Zheng, Songting Tan, Zhihong Yin, Chunguang Zhu, Yunqi Liu
Five-membered 1,3,4-oxadiazole (OZ) and 1,3,4-thiadiazole (TZ) heterocycle-based copolymers as active layer have long been ignored in solution-processable n-channel polymer field-effect transistors (PFETs) despite the long history of using OZ or TZ derivatives as the electron-injecting materials in organic light-emitting devices and their favorable electron affinities. Herein, we first report the synthesis and PFETs performance of two n-channel conjugated polymers bearing OZ- or TZ-based acceptor moieties, i...
December 7, 2016: ACS Applied Materials & Interfaces
Katarzyna Rybicka-Jasińska, Wenqian Shan, Katarzyna Zawada, Karl M Kadish, Dorota Gryko
Metalloporphyrins not only are vital in biological systems but also are valuable catalysts in organic synthesis. On the other hand, catalytic properties of free base porphyrins have been less explored. They are mostly known as efficient photosensitizers for the generation of singlet oxygen via photoinduced energy transfer processes, but under light irradiation, they can also participate in electron transfer processes. Indeed, we have found that free base tetraphenylporphyrin (H2TPP) is an efficient photoredox catalyst for the reaction of aldehydes with diazo compounds leading to α-alkylated derivatives...
November 30, 2016: Journal of the American Chemical Society
Mohammad Zeeshan, Inderjeet Kaur, Joseph Joy, Ekta Saini, Gourab Paul, Abhinav Kaushik, Surbhi Dabral, Asif Mohmmed, Dinesh Gupta, Pawan Malhotra
Plasmodium falciparum undergoes a tightly regulated developmental process in human erythrocytes, and recent studies suggest an important regulatory role of post-translational modifications (PTMs). As compared to Plasmodium phosphoproteome, little is known about other PTMs in the parasite. In the present study, we performed a global analysis of asexual blood stages of Plasmodium falciparum to identify arginine-methylated proteins. Using two different methyl arginine-specific antibodies we immunoprecipitated the arginine-methylated proteins from the stage-specific parasite lysates and identified 843 putative arginine methylated proteins by LC-MS/MS...
December 9, 2016: Journal of Proteome Research
Feng Chen, Yuxin Xing, Zhenqiang Wang, Xianying Zheng, Jixi Zhang, Kaiyong Cai
Well known for the adhesive property, mussel-inspired polydopamine (PDA) has been shown to enhance performance in a wide range of adsorption-based applications. However, imparting porous nanostructures to PDA materials for enhanced loading capacities has not been demonstrated even when surfactants were present in the synthesis. Herein, we report on the preparation of mesoporous PDA particles (MPDA) based on the assembly of primary PDA particles and Pluronic F127 stabilized emulsion droplets on water/1,3,5-trimethylbenzene (TMB) interfaces...
November 22, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Gang-Tian Zhu, Xiao-Mei He, Sheng He, Xi Chen, Shu-Kui Zhu, Yu-Qi Feng
Synthesis of functionalized mesoporous silica material with large particle size remains a chanllenge. In this work, polyethylenimine (PEI) functionalized mesoporous silica (PFMS) with particle size as large as 100 μm was successfully synthesized by a facile method. In the synthesis process, PEI served as four roles simultaneously, including functionalized reagent, alkaline catalyst, template for particle formation, and pore-structure-directing agent. The surface areas of the products were higher than 260 m(2)/g...
November 30, 2016: ACS Applied Materials & Interfaces
Qingxiang Wang, Yizhen Yang, Feng Gao, Jiancong Ni, Yanhui Zhang, Zhenyu Lin
A novel metal-organic framework (MOF)-based electroactive nanocomposite containing graphene fragments and HKUST-1 was synthesized via a facile one-step solvothermal method using graphene oxide (GO), benzene-1,3,5-tricarboxylic acid (BTC), and copper nitrate (Cu(NO3)2) as the raw materials. The morphology and structure characterization revealed that the GO could induce the transformation of HKUST-1 from octahedral structure to the hierarchical flower shape as an effective structure-directing agent. Also, it is interesting to find out that the GO was torn into small fragments to participate in the formation of HKUST-1 and then transformed into the reduction form during the solvothermal reaction process, which dramatically increased the surface area, electronic conductivity, and redox-activity of the material...
November 30, 2016: ACS Applied Materials & Interfaces
Hoon Ji, Sunhyun Hwang, Keonmok Kim, CheolGi Kim, Nak Cheon Jeong
The fabrication of metal-organic framework (MOF) films on conducting substrates has demonstrated great potential in applications such as electronic conduction and sensing. For these applications, direct contact of the film to the conducting substrate without a self-assembled monolayer (SAM) is a desired step that must be achieved prior to the use of MOF films. In this report, we propose an in situ strategy for the rapid one-step conversion of Cu metal into HKUST-1 films on conducting Cu substrates. The Cu substrate acts both as a conducting substrate and a source of Cu(2+) ions during the synthesis of HKUST-1...
November 30, 2016: ACS Applied Materials & Interfaces
Min Jiang, Haifang Li, Haijun Yang, Hua Fu
The formation of aryl C-S bonds is an important chemical transformation because aryl sulfides are valuable building blocks for the synthesis of biologically and pharmaceutically active molecules and organic materials. Aryl sulfides have traditionally been synthesized through the transition-metal-catalyzed cross-coupling of aryl halides with thiols. However, the aryl halides used are usually bromides and iodides; readily available, low-cost aryl chlorides often not reactive enough. Furthermore, the deactivation of transition-metal catalysts by thiols has forced chemists to use high catalyst loadings, specially designed ligands, high temperatures, and/or strong bases, thus leading to high costs and the incompatibility of some functional groups...
December 9, 2016: Angewandte Chemie
Megan K Mulligan, Khyobeni Mozhui, Pjotr Prins, Robert W Williams
The goal of systems genetics is to understand the impact of genetic variation across all levels of biological organization, from mRNAs, proteins, and metabolites, to higher-order physiological and behavioral traits. This approach requires the accumulation and integration of many types of data, and also requires the use of many types of statistical tools to extract relevant patterns of covariation and causal relations as a function of genetics, environment, stage, and treatment. In this protocol we explain how to use the GeneNetwork web service, a powerful and free online resource for systems genetics...
2017: Methods in Molecular Biology
Maryam Bordbar, Nafiseh Mortazavimanesh
Palladium nanoparticles (PdNPs) have been immobilized on the surface of walnut shell powder using Equisetum arvense L. leaf extract as reducing and stabilizing agents in this work. FT-IR spectroscopy, UV-Vis spectroscopy, photoluminescence spectroscopy, X-ray diffraction (XRD) pattern, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM) have been used in the characterization of the nanocomposites thus prepared. High catalytic activity was shown by these nanocomposites in the reduction of different dyes...
December 8, 2016: Environmental Science and Pollution Research International
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