Read by QxMD icon Read

Chemistry: a European Journal

Beat Ernst, Priska Frei, Lijuan Pang, Marleen Silbermann, Deniz Eris, Tobias Mühlethaler, Oliver Schwardt
Target-directed dynamic combinatorial chemistry (DCC) is an emerging technique for the efficient identification of inhibitors of pharmacologically relevant targets. In this contribution, we present an application for a bacterial target, the lectin FimH, a crucial virulence factor of uropathogenic E. coli being the main cause of urinary tract infections. A small dynamic library of acylhydrazones was formed from aldehydes and hydrazides and equilibrated at neutral pH in presence of aniline as nucleophilic catalyst...
June 27, 2017: Chemistry: a European Journal
Hanbit Park, D Amaranatha Reddy, Yujin Kim, Seunghee Lee, Rory Ma, Tae Kyu Kim
It is imperative to suppress the recombination rate of photogenerated carriers for the improvement of semiconductor-catalyzed solar-driven hydrogen production. To that end, photocatalysts comprising active sunlight-harvesting photoabsorbers and stable metal co-catalysts have attracted significant attention. However, the size, clean surface, and highly dispersed nature of the metal co-catalysts are crucial factors affecting the catalyst performance and reaction rate. Nevertheless, most of the available metal nanocrystals have been synthesized using complex procedures and harmful organic templates and stabilizers, affording high-purity compounds with difficulty and high cost...
June 27, 2017: Chemistry: a European Journal
Joel S Miller, Adora Graham, Matvey Fedin
[TCNE]*- (TCNE = tetracyanoethylene) has been isolated as D2h-- possessing a long, 2.9 Å 2e-/4c and as C2 π-[TCNE]22- possessing a 3.04 Å 2e-/6c bond. Temperature dependent UV-vis spectroscopic measurements in MeTHF led to the determination of the dimerization, 2 [TCNE]*-  π-[TCNE]22-, Keq(T), ∆H and ∆S, for [Mepy]2[TCNE]2 (Mepy = N-methylpyridinium) possessing D2h π-[TCNE]22- and [NMe4]2[TCNE]2 possessing C2 π-[TCNE]22- conformations in the solid state; however, both form D2h π-[TCNE]22- in solution...
June 27, 2017: Chemistry: a European Journal
Mario Schubert, Thomas Aeschbacher, Mirko Zierke, Martin Smieško, Mayeul Collot, Jean-Maurice Mallet, Beat Ernst, Frédéric H-T Allain
The increasing understanding of the essential role of carbohydrates in development, and in a wide range of diseases fuels a rapidly growing interest in the basic principles governing carbohydrate-protein interactions. A still heavily debated issue regarding the recognition process is the degree of flexibility or rigidity of oligosaccharides. Combining NMR structure determination based on extensive experimental data with density functional theory (DFT) and database searches, we have identified a set of trisaccharide motifs with a similar conformation that is characterized by a non-conventional C-H⋅⋅⋅O hydrogen bond...
June 27, 2017: Chemistry: a European Journal
Hans-Ulrich Reissig, Stefan Schoder, Scheghajeh Kord Daoroun Kalai
Starting from 3-alkoxy-2-aryl-substituted pyrroles and aromatic aldehydes, a collection of new dipyrromethenes was prepared. Under the standard conditions of Treibs, these were converted into the corresponding boron dipyrromethenes (BODIPYs). Compounds of this type with alkoxy groups at C-3 position of both pyrrole subunits are new and hence the photophysical properties of this collection of novel dipyrromethenes and BODIPY dyes were investigated. The dipyrromethenes show absorption maxima up to 596 nm and emissions of up to 677 nm...
June 27, 2017: Chemistry: a European Journal
Shiva Mohajernia, Seyedsina Hejazi, Anca Mazare, Nhat Truong Nguyen, Patrik Schmuki
In the present work we report on the key factors dictating the photo-electrochemical (PEC) performance of suboxide titania (TiOx) nanotubes. TiOx nanotubes were produced by a systematic variation of reduction heat treatments of TiO2 in Ar/H2. The properties of the TiOx tubes were investigated by electron paramagnetic resonance (EPR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), solid-state conductivity, reflectivity measurements, photocurrent spectroscopy, and photoelectrochemical hydrogen evolution...
June 27, 2017: Chemistry: a European Journal
Ya Du, Ryan Pearson, Chern Hooi-Lim, Steven Sartor, Matthew Ryan, Haishen Yang, Niels Damrauer, Garret Miyake
Photoredox catalysis is a versatile approach for the construction of challenging covalent bonds under mild reaction conditions, commonly using photoredox catalysts (PCs) derived from precious metals. As such, there is need to develop organic analogues as sustainable replacements. Although several organic PCs have been introduced, there remains a lack of strongly reducing visible light organic PCs. Herein, we establish the critical photophysical and electrochemical characteristics of both a dihydrophenazine and a phenoxazine system that enables them success as strongly reducing visible light PCs for trifluoromethylations and dual photoredox/nickel catalyzed C-N and C-S cross-couplings, reactions which have been historically exclusive to precious metal PCs...
June 27, 2017: Chemistry: a European Journal
Hans-Jörg Himmel, David Fridolin Schrempp, Elisabeth Kaifer, Hubert Wadepohl, Elisa Schneider
A new redox-active 4,5-bisguanidino-substituted o-benzoquinone ligand L is synthesized, that allows a rational access to heterobinuclear complexes by the sequential coordination of two metals. In the examples discussed in this work, mononuclear Cu and Pd complexes are prepared in a first coordination step, and these complexes are then used as precursors to homobinuclear [Cu(II)-L(0)-Cu(II)] and heterobinuclear [Pd(II)-L(0)-Cu(II)] complexes. In the heterobinuclear complex, the Pd(II) is coordinated by the softer bisguanidine side of L and the Cu(II) by the harder dioxolene side (in line with the HSAB concept)...
June 27, 2017: Chemistry: a European Journal
Zhiliang Luo, Liandong Feng, Ruibing An, Guanfu Duan, Runqi Yan, Hua Shi, Jian He, Zhengyang Zhou, Changge Ji, Hong-Yuan Chen, Deju Ye
γ-Glutamyl transpeptidase (GGT) is a cell membrane-bound enzyme that is involved in various physiological and pathological processes and is regarded as a potential biomarker for many malignant tumors, precise detection of which is useful for early cancer diagnosis. Herein, we reported a new GGT activatable near-infrared (NIR) fluorescence imaging probe (GANP) by linking of a GGT-recognitive substrate γ-glutamate (γ-Glu) and a NIR merocyanine fluorophore (mCy-Cl) with a self-immolative linker p-aminobenzyl alcohol (PABA)...
June 27, 2017: Chemistry: a European Journal
Donghuang Wang, Xinhui Xia, Yadong Wang, Dong Xie, Yu Zhong, Jianbo Wu, Xiuli Wang, Jiangping Tu
Construction of novel matrix with both high conductivity and excellent confinement effect for polysulfides is of great importance for developing high-performance lithium-sulfur (Li-S) batteries. In this work, we have developed a double-modification strategy to integrate lithium sulfide (Li2S) into the conductive composite network consisting of vertical graphene (VG) arrays and amorphous carbon shell forming integrated cathode (VG/Li2S-C). Facile liquid solution-evaporation plus CVD methods are successfully adopted for preparation of the above cathode...
June 27, 2017: Chemistry: a European Journal
Sanjukta Mukherjee, Chikara Dohno, Kazuhiko Nakatani
Cyclophane containing bis(2-amino-1,8-naphthyridine) moieties attached by variable linkers at the C-2 (linker B) were synthesized as cyclic mismatch binding ligand (CMBLs). Ring closing metathesis (RCM) is used as a key step for the introduction of double bond at the linker B. Decreasing the linker size of the substrate, formation of the RCM products with increasing trans:cis (E:Z) ratio was observed with moderate to high overall yield. Concentration dependent fluorescence spectra were observed for CMBLs with longer linkers (n = 3), whereas concentration independent spectra were observed for CMBLs with shorter linker length (n = 2 and/or 1) with a marked exception in (E)-alkene 6a...
June 27, 2017: Chemistry: a European Journal
Jingquan Liu, Aitang Zhang, Aihua Li, Wenxue Tian, Zichao Li, Chen Wei, Yong Sun, Wei Zhao, Mengli Liu
Molybdenum disulfide (MoS₂) nanosheets have attracted significant attention due to its photothermal properties, but the poor solubility and colloidal stability limited its further application in biomedical field. Herein, we report a targeted photothermal controllable nanocarrier consisting of MoS₂ nanosheets modified with block copolymer P(OEG-A)-b-P(VBA-co-KH570) and targeting ligand transferrin. P(OEG-A)-b-P(VBA-co-KH570) is synthesized by RAFT polymerization and utilized not only to improve the solubility of MoS₂ nanosheets but also efficiently load the anti-cancer drug doxorubicin (DOX) via acid-cleavable Schiff base linker...
June 27, 2017: Chemistry: a European Journal
Youn Sang Kim, Sanghun Cho, Yong-Keon Ahn, Zhenxing Yin, Duck-Jae You, Hyunjin Kim, Yuanzhe Piao, Jeeyoung Yoo
A novel copper oxide / graphite composite (GCuO) anodes with high capacity and long cycle-ability are proposed by one-step simple synthesis method. The GCuO is produced by the heat treatment of Cu ion complex and pristine graphite. The gases generated during thermal decomposition of the Cu ion complex (H2 and CO2) induce interlayer expansion of graphite planes, which assists effective ion intercalation. Also, Cu oxide is simultaneously formed as high capacity anode materials via thermal reduction of the Cu ion complex...
June 27, 2017: Chemistry: a European Journal
Rodolphe Clerac, Kasper Pedersen, Daniel Wooddruff, Saurabh Kumar Singh, Alain Tressaud, Etienne Durand, Mihail Atanasov, Panagiota Perlepe, Katharina Ollefs, Fabrice Wilhelm, Corine Mathonière, Frank Neese, Andrei Rogalev, Jesper Bendix
Heavy 5d elements, like osmium, feature strong spin-orbit interaction which is at the origin of exotic physical behaviors. Revealing the full potential of e.g. novel osmium oxide materials ("osmates") is however contingent upon a detailed understanding of the local single-ion properties. Herein, we report on two molecular osmate analogues, [OsF6]2- and [OsF6]-, as model systems for Os4+ and Os5+ centres found in oxides. Using X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) techniques combined with state-of-the-art ab initio calculations, we elucidate their ground state, which is mirroring the osmium electronic structure in osmates...
June 26, 2017: Chemistry: a European Journal
Xiaogang Qu, Jiasi Wang, Hongshuang Qin, Faming Wang, Jinsong Ren
Telomerase is a key regulator in cell metabolism, tissue renewal and organismal lifespan. Here we develop a simple strategy to modulate cellular telomerase activity, and further control cell fate based on Mg2+ and Zn2+ activated DNAzymes in living cells. Through modulation of telomerase activity, we can regulate cell behavior, including cell migration, cell differentiation, cell senescence and cell cycle. Our work provides a new way to modulate telomerase activity in living cells by using DNAzymes.
June 26, 2017: Chemistry: a European Journal
Max C Holthausen, Felix Neumeyer, Julia I Schweizer, Lioba Meyer, Alexander G Sturm, Andor Nadj, Norbert Auner
A combined experimental and theoretical study of the high-temperature reaction of SiCl4 and elemental silicon is presented. The nature and reactivity of the product formed upon rapid cooling of the gaseous reaction mixture is investigated by comparison with defined model compounds, i.e. cyclo-Si5Cl10, n-Si5Cl12 and n-Si4Cl10. A DFT assessment provides mechanistic insight into the oligosilane formation. Experimental 29Si NMR investigations, supported by quantum-chemical 29Si NMR calculations, consistently show that the reaction product is composed of discrete molecular perchlorinated oligosilanes...
June 26, 2017: Chemistry: a European Journal
Rafid Dawood, Irene Georgiou, Ross Wilkie, William Lewis, Robert Andrew Stockman
A simple and efficient asymmetric synthesis of novel sp3-rich pyrrolidine chemical scaffolds over five steps starting from simple ketones is described. Key steps involve the use of tert-butanesulfinamide as a chiral auxiliary to perform an asymmetric Tsuji-Trost allylation, with subsequent cross-metathesis with an acrylate ester and reduction of the sulfinimine/cyclisation of the resulting amine giving the pyrrolidine scaffolds in high yields and diastereoselectivites. By removing the chiral auxiliary and functionalising the ester group, the resulting scaffold core can be further derivatised...
June 26, 2017: Chemistry: a European Journal
Daniel Lachmann, Carolin Studte, Barbara Männel, Harald Huebner, Peter Gmeiner, Burkhard König
We describe the incorporation of the well-investigated class of photochromic dithienylethenes (DTEs) and fulgides into known dopamine receptor ligands like 1,4-disubstituted aromatic and hydroxybenzoxazinone piperazines as well as aminoindanes. Subtype and functional selective photochromic ligands were obtained and characterized by NMR and UV-VIS spectroscopic measurements. The photophysical properties of the DTE based dopamine ligands revealed a high fatigue resistance for the diarylmaleimides, but the ringclosure could not be accomplished in polar solvents due to a known twisted intramolecular charge transfer (TICT)...
June 26, 2017: Chemistry: a European Journal
Herbert W Roesky, Sudipta Roy, Kartik Chandra Mondal, Bin Li, Subrata Kundu, Christian J Schürmann, Sayan Dutta, Debasis Koley, Dietmar Stalke, Regine Herbst-Irmer
The cyclic alkyl(amino) carbene (cAAC) bonded chlorophosphinidene (cAAC)P-Cl (2/2´) was isolated from the direct reaction between cAAC and phosphorus trichloride (PCl3). Compound 2/2´ has been characterized by NMR and mass spectrometry. 31P NMR investigations [~160 ppm (major) and ~130 ppm (minor)] structural determination reveal that there are two different P environments of P-Cl unit. X-ray single crystal determination suggests a co-crystallization of two conformational isomers of (cAAC)P-Cl (2/2´); the major compound possessing a cAAC-PCl unit with CcAAC-P 1...
June 26, 2017: Chemistry: a European Journal
Andreas Jarzebski, Christina Tenten, Christoph Bannwarth, Gregor Schnakenburg, Stefan Grimme, Arne Lützen
A new bis(salicylimine) ligand based on the Tröger's base scaffold was synthesized in racemic and enantiomerically pure form. Upon coordination to zinc(II) ions this ligand undergoes highly diastereoselective self-assembly into neutral dinuclear double-stranded helicates as proven by XRD analysis and via comparison of experimental ECD-spectra with those simulated with quantum chemical methods. When the racemic ligand was used self-assembly occurs under narcissistic self-sorting resulting in the formation of a racemic pair of helicates as revealed by NMR spectroscopy and XRD analysis...
June 26, 2017: Chemistry: a European Journal
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"