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Chemistry: a European Journal

Cortney von Hahmann, Maria Talavera, Conghui Xu, Thomas Braun
The rhodium complexes [Rh(C≡CCF3)(PEt3)3] (2), fac-[RhH(C≡CCF3)2(PEt3)3] (3), and fac-[Rh{(E)-CH=CHCF3}(C≡CCF3)2(PEt3)3] (4) were synthesised by reactions of rhodium(I) complexes [Rh(H)(PEt3)3] (1) and [Rh(Bpin)(PEt3)3] (5) with the alkyne 3,3,3-trifluoropropyne. Reactivity studies of [Rh(C≡CCF3)(PEt3)3] (2) were performed with CO and 13CO to form [Rh(C≡CCF3)(CO)(PEt3)3] (7) and subsequently trans-[Rh(C≡CCF3)(CO)(PEt3)2] (8) as well as the labelled derivatives. Using 1-4 as catalysts, hydroboration reactions selectively afforded borylated building blocks...
May 23, 2018: Chemistry: a European Journal
Yixuan Lin, Kenward Vong, Koji Matsuoka, Katsunori Tanaka
Previously, Au(III) complexes coordinated with 2-benzoylpyridine ligand, BPy-Au, were prebound to a protein and used to discover a novel protein-directed labelling approach with propargyl ester functional groups. In this work, further examination discovered that gold catalysts devoid of the 2-benzoylpyridine ligand (ex/ NaAuCl4) had significantly reduced levels of protein labeling. Mechanistic investigations then revealed that BPy-Au and propargyl esters undergo a rare example of C(sp2)-C(sp) aryl-alkynyl cross coupling, likely via spontaneous reductive elimination...
May 23, 2018: Chemistry: a European Journal
Jung Kyu Lee, Insung S Choi, Tong In Oh, EunAh Lee
Stem cells opened great opportunity to overcome diseases that conventional therapy had only limited success. Use of scaffolds made from biomaterials not only helps handling of stem cells for delivery or transplantation but also supports enhanced cell survival. Likewise, cell encapsulation can provide stability for living animal cells even in a state of separateness. Although various chemical reactions were tried to encapsulate stolid microbial cells such as yeasts, a culture environment for the growth of animal cells allows only highly biocompatible reactions...
May 23, 2018: Chemistry: a European Journal
Paula Sanz Camacho, Martin Stanford, David McKay, Daniel Dawson, Kasun Athukorala Arachchige, David Cordes, Alexandra Slawin, Derek Woollins, Sharon E Ashbrook
A series of novel P-E containing heterocycles with aromatic backbones were synthesised and characterized by single crystal and powder X-ray diffraction, microanalysis and mass spectrometry. 31P and 77Se solution- and solid-state NMR spectroscopy revealed significant differences between the NMR parameters in solution and in the solid state, related to conformational changes in the molecules. Many compounds were shown to exhibit a number of different polymorphic structures (identified by single-crystal XRD), although the bulk material studied by solid-state NMR often contained just one major polymorph...
May 23, 2018: Chemistry: a European Journal
Monica Helvia Perez-Temprano, Sara Martínez de Salinas, Angel Luis Mudarra, Jordi Benet-Buchholz, Teodor Parella, Feliu Maseras
This work describes the employment of discrete "AgCF₃" complexes, including unique (Cat)[Ag(CF₃)₂] salts, as efficient transmetalating agents to PdII in order to tackle some of the usually overshadowed limitations related to this step within the trifluoromethylation area.
May 23, 2018: Chemistry: a European Journal
Bipin Kumar Gupta, Amit Kumar Gangwar, Ashish Gupta, Garima Kedawat, Pawan Kumar, Bhanu Pratap Singh, Nidhi Singh, Avanish K Srivastava, Sanjay R Dhakate
Recently, increasing trend of counterfeiting of the important data, currency, stamp papers, branded products etc. has become a major security threat which could lead to a serious damage to global economy. Consequences of these damages are enforcing to researcher for developing new high-end security features to address its full proof solutions. Herein, we report a dual mode flexible highly luminescent white security paper and nanotaggants composed of nanophosphors incorporated in polymer metrics to form the nanofibers based mat for anti-counterfeiting applications...
May 23, 2018: Chemistry: a European Journal
Matouš Krömer, Kateřina Bártová, Veronika Raindlová, Michal Hocek
(3,4-Dihydroxybut-1-ynyl)uracil, -cytosine and -7-deazaadenine 2'-deoxyribonucleoside triphosphates (dNTPs) were prepared by direct aqueous Sonogashira cross-coupling of halogenated dNTPs with dihydroxybut-1-yne and converted to 3,4-dihydroxybutyl dNTPs through catalytic hydrogenation. Sodium periodate oxidative cleavage of dihydroxybutyl-dUTP gave the desired aliphatic aldehyde-linked dUTP, whereas the oxidative cleavage of the corresponding deazaadenine dNTP gave a cyclic aminal. All dihydroxyalkyl or -alkynyl dNTPs and the formylethyl-dUTP were good substrates for DNA polymerases and were used for synthesis of diol- or aldehyde-linked DNA...
May 23, 2018: Chemistry: a European Journal
Lukas Reith, Karla Lienau, Daniel S Cook, René Moré, Richard I Walton, Greta Ricarda Patzke
The hydrothermal growth of cobalt oxide spinel (Co₃O₄) nanocrystals from cobalt acetate precursors was monitored with in situ powder X-ray diffraction (PXRD) in combination with ex situ electron microscopy and vibrational spectroscopy. Kinetic data from in situ PXRD monitoring were analyzed using Sharp-Hancock and Gualtieri approaches, which both clearly indicate a change of the growth mechanism for reaction temperatures above 185°C. This mechanistic transition goes hand in hand with morphology changes that notably influence the photocatalytic oxygen evolution activity...
May 23, 2018: Chemistry: a European Journal
Bin Zhao, Huan-Cheng Hu
A new concept for constructing metal-organic frameworks (MOFs) based on multicentre-bonded [MI]8 (M = Mn, Zn) clusters with cubic aromaticity is discussed. In principle, intermolecular/intramolecular hydrogen-bonding, π***π stacking, coordinated covalent bonding and ionic bonding usually account for the structures of MOFs, and multicentered bonds generally exist in cation, anion, neutral and zwitterionic radicals, while rarely appear in MOFs. Meanwhile, aromaticity became one of the most vexing yet fascinating key concepts in chemistry since the proposition of the structure of benzene molecule in 1865...
May 23, 2018: Chemistry: a European Journal
Jian Fan, Xiang-Yang Liu, Yu-Yang Ma, Wenjuan Zhang, Bo Song, Lei Ding, Man-Keung Fung
Three novel 9,10-dihydroacridine derivatives, 4'-(10-methyl-9,9-diphenyl-9,10-dihydroacridin-4-yl)-[1,1'-biphenyl]-4-carbonitrile (MeAcPhCN), 4'-(9,9,10-triphenyl-9,10-dihydroacridin-4-yl)-[1,1'-biphenyl]-4-carbonitrile (PhAcPhCN), and 5-(4-(9,9,10-triphenyl-9,10-dihydroacridin-4-yl)phenyl)picolinonitrile (MeAcPyCN), were prepared by the attachment of [1,1'-biphenyl]-4-carbonitrile or 5-phenylpicolinonitrile to the 4-position of 9,10-dihydroacridine. This special linking strategy will limit the conjugation length, maintain the triplet energy and inhibit the intermolecular charge transfer (ICT) characteristics for these compounds...
May 22, 2018: Chemistry: a European Journal
Zhibing Sun, Shihang Yu, Lili Zhao, Jifeng Wang, Zifeng Li, Gang Li
This work reports on the design and fabrication of a proton conductive 2D MOF, [Cu(p-IPhHIDC)]n (1) (p-IPhH3IDC = 2-(p-N-imidazol-1-yl)-phenyl-1H-imidazole-4,5dicarboxylic acid) as an advanced ammonia impedance sensor at room temperature and 68-98% RHs. MOF 1 shows the optimized proton conductivity value of 1.51 × 10-3 S·cm-1 at 100 C and 98% RH. Its temperature-dependent and humidity-dependent proton conduction properties have been explored. The large amount of uncoordinated carboxylate groups between the layers play a vital role in the resultant conductivity...
May 22, 2018: Chemistry: a European Journal
Ewa Nowicka, Niamh Hickey, Meenakshisundaram Sankar, Robert L Jenkins, David W Knight, David J Willock, Graham J Hutchings, Manuel Francisco, Stuart H Taylor
Ruthenium ion catalyzed oxidation (RICO) of polyaromatic hydrocarbons (PAHs) has been studied in detail using experimental and computational approaches to explore the reaction mechanism. DFT calculations show that regioselectivity in these reactions can be understood in terms of the preservation of aromaticity in the initial formation of a [3+2] metallocycle intermediate at the most isolated double bond. We identify two competing pathways: C-C bond cleavage leading to a dialdehyde and C-H activation followed by H migration to the RuOx complex to give diketones...
May 22, 2018: Chemistry: a European Journal
Jacob Davies, Sara P Morcillo, James J Douglas, Daniele Leonori
In recent years hydroxylamines derivatives have been exploited as nitrogen-radical precursors in visible-light photochemistry. Their ability to serve as electrophores in redox chemistry has propelled the development of many novel transformations. The fundamental mechanistic aspects as well as the importance in the preparation of nitrogen-containing molecules will be highlighted.
May 22, 2018: Chemistry: a European Journal
Stefanie Dehnen, Katharina Hanau, Niklas Rinn, Mario Argentari
Several compounds with unique structural motifs that have already been known from organotin sulfide chemistry, but remained unprecedented in organotin selenide chemistry so far, have been synthesized. The reaction of [(R1Sn)4Se6] (R1 = CMe2CH2C(O)Me) with N2H4·H2O/(SiMe3)2Se and with PhN2H3/(SiMe3)2Se led to the formation of [{(R2Sn)2SnSe4}2(µ-Se)2] (1) and [{(R3Sn)2SnSe4}2(µ-Se)2] (2) (R2 = CMe2CH2C(Me)NNH2, R3 = CMe2CH2C(Me)NNPhH), respectively. Addition of o-phthalaldehyde to [(R2Sn)4Se6] yielded a cluster with intramolecular bridging of the organic groups, [(R4Sn2)2Se6] (3, R4 = (CMe2CH2C(Me)NNCH)2C6H4)...
May 22, 2018: Chemistry: a European Journal
Yanzi Xu, Lin Ren, Dongfeng Dang, Ying Zhi, Xiaochi Wang, Lingjie Meng
Currently, the commonly developed organic luminescent materials (OLMs) usually exhibit poor luminescent performance in aggregated solid states compared with their well-dissolved solution states, making it a tough goal to achieve the highly emissive dual-state emission. To overcome this limitation, "Self-Isolated Enhanced Emission" (SIEE) strategy through flexible alkyl chains to suppress the emission-quenched π-π stacking in solids is proposed here and based on this guideline, remarkable emission efficiency with photoluminescence quantum yields up to 99...
May 22, 2018: Chemistry: a European Journal
Tsuyoshi Kato, Masayuku Nakagaki, Antoine Baceiredo, Shigeyoshi Sakaki
Although oxidative addition (O.A.) and reductive elimination (R.E.) are exceedingly important processes in organometallic chemistry, such processes are still extremely rare for main group element species. Here we report a theoretical study on the reaction of phosphine-stabilized silylenes with silanes which proceeds via reversible O.A./R.E. at room temperature. Of particular interest, this theoretical approach highlights the important role of the ligand, which can greatly affect kinetics and energy balance of the reaction...
May 22, 2018: Chemistry: a European Journal
Qinfeng Rong, Wenwei Lei, Mingjie Liu
Flexible conductive materials have gained considerable research interest in recent years because of their potential applications in flexible energy storage devices, sensors, touch panels, electronic-skins, etc. With excellent flexibility, outstanding electric properties and tunable mechanical properties, conductive hydrogels as conductive materials offer plentiful insights and opportunities for flexible electronic devices. Numerous synthetic strategies have been developed to obtain various conductive hydrogels, and high-performance devices based on these conductive hydrogels have been realized...
May 22, 2018: Chemistry: a European Journal
Laura Jowett, Ethan Howe, Xin Wu, Nathalie Busschaert, Philip Alan Gale
The anion transport properties of a series of previously reported tren-based anionophores have been revisited using new assays designed to measure anion uniport. This study provides new insights into the transport mechanism and selectivity of this important class of transporters. Specifically, we report the chloride and nitrate transport selectivity of these systems and quantify sulfate transport to determine EC50 values for sulfate transport for the first time. Two new assays were developed to study bicarbonate transport allowing accurate quantification of chloride/bicarbonate exchange...
May 22, 2018: Chemistry: a European Journal
M Concepción Gimeno, Alice Johnson, Isabel Marzo
The reactivity of the phosphonium salt, (cyanomethyl)triphenylphosphonium chloride, and the ylide, triphenylphosphoniumcyanomethylide, towards group eleven metal complexes is described. Mononuclear neutral gold(I) and gold(III) complexes of the type [AuX{CH(CN)PPh3}] or [AuX3{CH(CN)PPh3}], and cationic derivatives such as [AuL{CH(CN)PPh3}]X have been prepared. Surprisingly the cationic gold species could only be prepared with ligands with a large steric hindrance such as bulky NHCs or the JohnPhos phosphine, in contrast with silver and copper derivatives which have dimeric structures with coordination to the cyano group of the ylide...
May 22, 2018: Chemistry: a European Journal
Si-Si Sun, Zheng Wang, Xiang Wen Wu, Jian-Hua Zhang, Chao-Jie Li, Shao-Yun Yin, Ling Chen, Mei Pan, Cheng-Yong Su
Two series of isostructural lanthanide coordination complexes, namely, LIFM-42(Ln), Ln = Eu, Tb, Gd, and LIFM-43(Ln), Ln = Er, Yb) were synthesized through the self-assembly of an ESIPT (excited-state intramolecular proton transfer) ligand, H2hpi2cf (5-(2-(5-fluoro-2-hydroxyphenyl)-4,5-bis(4-fluorophenyl)-1H-imidazol-1-yl)isophthalic acid) with different lanthanide ions. In the coordination structures linked by the ligands and oxo-bridged LnIII2 clusters (for LIFM-42(Ln) series) or isolated LnIII ions (for LIFM-43(Ln) series), the ESIPT ligand can serve as both the host and antenna for protecting and sensitizing the photoluminescence (PL) of LnIII ions...
May 22, 2018: Chemistry: a European Journal
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