bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Properties of Lanthanide Ruthenium(III) Oxide Perovskites
Authors: Sinclair Alexandra , Rodgers Jennifer A. , Topping Craig V. , Míšek Martin , Stewart Ross D. , Kockelmann Winfried , Bos Jan‐Willem G. , Attfield J. Paul 
Published: June 2014

AbstractAn extensive series of new LnRuO3 perovskites has been synthesized at high pressure. These ruthenium(III)‐based oxides are ruthenium deficient, and high‐pressure samples have compositions close to LnRu0.9O3. These phases stabilize ruthenium(III) which is very unusual in oxides. X‐ray and neutron powder diffraction studies show that the materials adopt orthorhombic perovskite superstructures in which the RuO6 octahedra are tetragonally compressed. These distortions, and the Mott insulator properties of the materials, are driven by strong spin‐orbit coupling.
Strontium Vanadium Oxide–Hydrides: “Square‐Planar” Two‐Electron Phases
Authors: Denis Romero Fabio , Leach Alice , Möller Johannes S. , Foronda Francesca , Blundell Stephen J. , Hayward Michael A. 
Published: June 2014

AbstractA series of strontium vanadium oxide–hydride phases prepared by utilizing a low‐temperature synthesis strategy in which oxide ions in Srn+1VnO3n+1 (n=∞, 1, 2) phases are topochemically replaced by hydride ions to form SrVO2H, Sr2VO3H, and Sr3V2O5H2, respectively. These new phases contain sheets or chains of apex‐linked V3+O4 squares stacked with SrH layers/chains, such that the n=∞ member, SrVO2H, can be considered to be analogous to “infinite‐layer” phases, such as Sr1−xCaxCuO2 (the parent phase of the high‐Tc cuprate superconductors), but with a d2 electron count. All three oxide–hydride phases exhibit strong antiferromagnetic coupling, with SrVO2H exhibiting an antiferromagnetic ordering temperature, TN>300 K. The strong antiferromagnetic couplings are surprising given they appear to arise from π‐type magnetic exchange.
Structurally Homogeneous Nanosheets from Self‐Assembly of a Collagen‐Mimetic Peptide
Authors: Jiang Tao , Xu Chunfu , Zuo Xiaobing , Conticello Vincent P. 
Published: June 2014

AbstractA collagen‐mimetic peptide, NSIII, has been designed with three sequential blocks having positive, neutral, and negative charges, respectively. The non‐canonical imino acid, (2S,4S)‐4‐aminoproline (amp), was used to specify the positive charges at the Xaa positions of (Xaa‐Yaa‐Gly) triads in the N‐terminal domain of NSIII. Peptide NSIII underwent self‐assembly from aqueous solution to form a highly homogeneous population of nanosheets. Two‐dimensional crystalline sheets formed in which the length of the peptide defined the height of the sheets. These results contrasted with prior results on a similar multi‐domain collagen‐mimetic polypeptides in which the sheets had highly polydisperse distribution of sizes in the (x/y)‐ and (z)‐dimensions. The structural differences between the two nanosheet assemblies were interpreted in terms of the relative stereoelectronic effects of the different aminoproline derivatives on the local triple helical conformation of the peptides.
Synthesis of a Specified, Silica Molecular Sieve by Using Computationally Predicted Organic Structure‐Directing Agents
Authors: Schmidt Joel E. , Deem Michael W. , Davis Mark E. 
Published: June 2014

AbstractCrystalline molecular sieves are used in numerous applications, where the properties exploited for each technology are the direct consequence of structural features. New materials are typically discovered by trial and error, and in many cases, organic structure‐directing agents (OSDAs) are used to direct their formation. Here, we report the first successful synthesis of a specified molecular sieve through the use of an OSDA that was predicted from a recently developed computational method that constructs chemically synthesizable OSDAs. Pentamethylimidazolium is computationally predicted to have the largest stabilization energy in the STW framework, and is experimentally shown to strongly direct the synthesis of pure‐silica STW. Other OSDAs with lower stabilization energies did not form STW. The general method demonstrated here to create STW may lead to new, simpler OSDAs for existing frameworks and provide a way to predict OSDAs for desired, theoretical frameworks.
Discovery and Application of Doubly Quaternized Cinchona‐Alkaloid‐Based Phase‐Transfer Catalysts
Authors: Xiang Bangping , Belyk Kevin M. , Reamer Robert A. , Yasuda Nobuyoshi 
Published: June 2014

AbstractWe report the discovery of novel N,N′‐disubstituted cinchona alkaloids as efficient phase‐transfer catalysts for the assembly of stereogenic quaternary centers. In comparison to traditional cinchona‐alkaloid‐based phase‐transfer catalysts, these new catalysts afford substantial improvements in enantioselectivity and reaction rate for intramolecular spirocyclization reactions with catalyst loadings as low as 0.3 mol % under mild conditions.
Pure In‐Phase Heteronuclear Correlation NMR Experiments
Authors: Castañar Laura , Saurí Josep , Williamson Robert Thomas , Virgili Albert , Parella Teodor 
Published: June 2014

AbstractA general NMR approach to provide pure in‐phase (PIP) multiplets in heteronuclear correlation experiments is described. The implementation of a zero‐quantum filter efficiently suppresses any unwanted anti‐phase contributions that usually distort the multiplet pattern of cross‐peaks and can hamper their analysis. The clean pattern obtained in PIP‐HSQMBC experiments is suitable for a direct extraction of coupling constants in resolved signals, for a peak‐fitting process from a reference signal, and for the application of the IPAP technique in non‐resolved multiplets.
Temperature‐ and Voltage‐Induced Ligand Rearrangement of a Dynamic Electroluminescent Metallopolymer
Authors: Asil Demet , Foster Jonathan A. , Patra Asit , de Hatten Xavier , del Barrio Jesús , Scherman Oren A. , Nitschke Jonathan R. , Friend Richard H. 
Published: June 2014

AbstractA dynamic‐covalent metal‐containing polymer was synthesized by the condensation of linear diamine and dialdehyde subcomponents around copper(I) templates in the presence of bidentate phosphine ligands. In solution, the red polymers undergo a sol–gel transition upon heating to form a yellow gel, a process that can be either reversible or irreversible depending on the solvent used. When fabricated into a light‐emitting electrochemical cell (LEC), the polymer emits infrared light at low voltage. As the voltage is increased, a blue shift in the emission wavelength is observed until yellow light is emitted, a process which is gradually reversed over time upon lowering the voltage. The mechanism underlying these apparently disparate responses is deduced to be due to loss of the copper phosphine complex from the polymer.
Functionalization of Alkynes by a (Salen)ruthenium(VI) Nitrido Complex
Authors: Man Wai‐Lun , Xie Jianhui , Lo Po‐Kam , Lam William W. Y. , Yiu Shek‐Man , Lau Kai‐Chung , Lau Tai‐Chu 
Published: June 2014

AbstractExploring new reactivity of metal nitrides is of great interest because it can give insights to N2 fixation chemistry and provide new methods for nitrogenation of organic substrates. In this work, reaction of a (salen)ruthenium(VI) nitrido complex with various alkynes results in the formation of novel (salen)ruthenium(III) imine complexes. Kinetic and computational studies suggest that the reactions go through an initial ruthenium(IV) aziro intermediate, followed by addition of nucleophiles to give the (salen)ruthenium(III) imine complexes. These unprecedented reactions provide a new pathway for nitrogenation of alkynes based on a metal nitride.
Continuous Flow Synthesis of Ketones from Carbon Dioxide and Organolithium or Grignard Reagents
Authors: Wu Jie , Yang Xiaoqing , He Zhi , Mao Xianwen , Hatton T. Alan , Jamison Timothy F. 
Published: June 2014

AbstractWe describe an efficient continuous flow synthesis of ketones from CO2 and organolithium or Grignard reagents that exhibits significant advantages over conventional batch conditions in suppressing undesired symmetric ketone and tertiary alcohol byproducts. We observed an unprecedented solvent‐dependence of the organolithium reactivity, the key factor in governing selectivity during the flow process. A facile, telescoped three‐step–one‐flow process for the preparation of ketones in a modular fashion through the in‐line generation of organometallic reagents is also established.
Discovery of Cell‐Permeable Inhibitors That Target the BRCT Domain of BRCA1 Protein by Using a Small‐Molecule Microarray
Authors: Na Zhenkun , Pan Sijun , Uttamchandani Mahesh , Yao Shao Q. 
Published: June 2014

AbstractBRCTs are phosphoserine‐binding domains found in proteins involved in DNA repair, DNA damage response and cell cycle regulation. BRCA1 is a BRCT domain‐containing, tumor‐suppressing protein expressed in the cells of breast and other human tissues. Mutations in BRCA1 have been found in ca. 50 % of hereditary breast cancers. Cell‐permeable, small‐molecule BRCA1 inhibitors are promising anticancer agents, but are not available currently. Herein, with the assist of microarray‐based platforms, we have discovered the first cell‐permeable protein–protein interaction (PPI) inhibitors against BRCA1. By targeting the (BRCT)2 domain, we showed compound 15 a and its prodrug 15 b inhibited BRCA1 activities in tumor cells, sensitized these cells to ionizing radiation‐induced apoptosis, and showed synergistic inhibitory effect when used in combination with Olaparib (a small‐molecule inhibitor of poly‐ADP‐ribose polymerase) and Etoposide (a small‐molecule inhibitor of topoisomerase II). Unlike previously reported peptide‐based PPI inhibitors of BRCA1, our compounds are small‐molecule‐like and could be directly administered to tumor cells, thus making them useful for future studies of BRCA1/PARP‐related pathways in DNA damage and repair response, and in cancer therapy.
The Intermetalloid Cluster [(Cp*AlCu)6H4], Embedding a Cu6 Core Inside an Octahedral Al6 Shell: Molecular Models of Hume–Rothery Nanophases
Authors: Ganesamoorthy Chelladurai , Weßing Jana , Kroll Clarissa , Seidel Rüdiger W. , Gemel Christian , Fischer Roland A. 
Published: June 2014

AbstractDefined molecular models for the surface chemistry of Hume–Rothery nanophases related to catalysis are very rare. The Al‐Cu intermetalloid cluster [(Cp*AlCu)6H4] was selectively obtained from the clean reaction of [(Cp*Al)4] and [(Ph3PCuH)6]. The stronger affinity of Cp*Al towards Cu sweeps the phosphine ligands from the copper hydride precursor and furnishes an octahedral Al6 cage to encapsulate the Cu6 core. The resulting hydrido cluster M12H4 reacts with benzonitrile to give the stoichiometric hydrometalation product [(Cp*AlCu)6H3(N=CHPh)].
Chemistry with Graphene and Graphene Oxide—Challenges for Synthetic Chemists
Authors: Eigler Siegfried , Hirsch Andreas 
Published: June 2014

AbstractThe chemical production of graphene as well as its controlled wet chemical modification is a challenge for synthetic chemists. Furthermore, the characterization of reaction products requires sophisticated analytical methods. In this Review we first describe the structure of graphene and graphene oxide and then outline the most important synthetic methods that are used for the production of these carbon‐based nanomaterials. We summarize the state‐of‐the‐art for their chemical functionalization by noncovalent and covalent approaches. We put special emphasis on the differentiation of the terms graphite, graphene, graphite oxide, and graphene oxide. An improved fundamental knowledge of the structure and the chemical properties of graphene and graphene oxide is an important prerequisite for the development of practical applications.
One Hundred Years of the Max‐Planck‐Institut für Kohlenforschung
Authors: Reetz Manfred T. 
Published: June 2014

AbstractThis Essay is an account of the institutional and scientific development of the Max‐Planck‐Institut für Kohlenforschung in Mülheim an der Ruhr (Germany), which is the successor to the Kaiser‐Wilhelm‐Institut für Kohlenforschung founded in 1914. The Essay is divided into four main parts, corresponding to the four major periods which are closely associated with the respective Directors of the Institute from 1914 to 2014: 1) Franz Fischer; 2) Karl Ziegler; 3) Günther Wilke; and 4) the period beginning with Manfred T. Reetz, who established a directorate comprising five Directors of equal status, each heading a different research department under the banner of catalysis. Along with key historical events associated with the Institute, research highlights of the four periods are featured.
Synchronization of Two Assembly Processes To Build Responsive DNA Nanostructures
Authors: Nie Zhou , Wang Pengfei , Tian Cheng , Mao Chengde 
Published: June 2014

AbstractHerein, we report a strategy for the synchronization of two self‐assembly processes to assemble stimulus‐responsive DNA nanostructures under isothermal conditions. We hypothesized that two independent assembly processes, when brought into proximity in space, could be synchronized and would exhibit positive synergy. To demonstrate this strategy, we assembled a ladderlike DNA nanostructure and a ringlike DNA nanostructure through two hybridization chain reactions (HCRs) and an HCR in combination with T‐junction cohesion, respectively. Such proximity‐induced synchronization adds a new element to the tool box of DNA nanotechnology. We believe that it will be a useful approach for the assembly of complex and responsive nanostructures.
Nanojunction‐Mediated Photocatalytic Enhancement in Heterostructured CdS/ZnO, CdSe/ZnO, and CdTe/ZnO Nanocrystals
Authors: Eley Clive , Li Tong , Liao Fenglin , Fairclough Simon Michael , Smith Jason M. , Smith George , Tsang Shik Chi Edman 
Published: June 2014

AbstractA series of highly efficient semiconductor nanocrystal (NC) photocatalysts have been synthesized by growing wurtzite‐ZnO tetrahedrons around pre‐formed CdS, CdSe, and CdTe quantum dots (QDs). The resulting contact between two small but high‐quality crystals creates novel CdX/ZnO heterostructured semiconductor nanocrystals (HSNCs) with extensive type‐II nanojunctions that exhibit more efficient photocatalytic decomposition of aqueous organic molecules under UV irradiation. Catalytic testing and characterization indicate that catalytic activity increases as a result of a combination of both the intrinsic chemistry of the chalcogenide anions and the heterojunction structure. Atomic probe tomography (APT) is employed for the first time to probe the spatial characteristics of the nanojunction between cadmium chalcogenide and ZnO crystalline phases, which reveals various degrees of ion exchange between the two crystals to relax large lattice mismatches. In the most extreme case, total encapsulation of CdTe by ZnO as a result of interfacial alloying is observed, with the expected advantage of facilitating hole transport for enhanced exciton separation during catalysis.
One‐, Two‐, and Three‐Electron Reduction of a Cyclic Alkyl(amino)carbene–SbCl3 Adduct
Authors: Kretschmer Robert , Ruiz David A. , Moore Curtis E. , Rheingold Arnold L. , Bertrand Guy 
Published: June 2014

AbstractA cyclic alkyl(amino)carbene readily reacts with SbCl3 to form the corresponding SbIII adduct. One‐electron reduction gives rise to the first example of a neutral antimony‐centered radical characterized in solution. Two‐electron reduction affords a Lewis base stabilized chloro‐stibinidene, whereas three‐electron reduction gives an antimony diatomic species capped by two carbenes. The radical has been characterized by EPR spectroscopy, while the structure of the other three species has been ascertained by single‐crystal X‐ray diffraction. In these four species, the formal oxidation state of the metalloid diminishes from III, to II, to I, and finally 0.
A New Regional Cold War?American andChinese Posturing in thePacific
Authors: Ratuva Steven 
Published: June 2014

AbstractIt is often argued that theUnitedStates andChinese engagement in thePacific manifests a clash of foreign policies that mimics the cold war confrontation of the post‐WorldWar II era. The article argues that rather than a dichotomous contestation of foreign policies, theUnitedStates–China engagement is more complex in nature and needs to be understood using more ‘syncretic’ lenses to understand the complex synergy in their relationship, which oscillates between tension and accommodation, cooperation and competition. While there are areas of policy contestation, there are also areas of policy appeasement and convergence. This may act as a stabilising factor in the region as the two powers acknowledge the significance of the other and the long‐term cost of direct confrontation on their respective interests. This potentially contributes to a ‘stable’ environment where thePacificIslandCountries are prevented from taking sides, which could potentially exacerbate tension and regional instability.
Immobilization of Enzymes on 2‐Hydroxyethyl Methacrylate and Glycidyl Methacrylate Copolymer Brushes
Authors: Ren Tanchen , Mao Zhengwei , Moya Sergio Enrique , Gao Changyou 
Published: June 2014

AbstractThe immobilization of enzymes is of paramount importance to maintain their activity and stability. In this study, surface‐initiated atom‐transfer radical polymerization was applied to prepare poly(2‐hydroxyethyl methacrylate)‐block‐poly(2‐hydroxyethyl methacrylate‐co‐glycidyl methacrylate) brushes on glass slides. The polymerization kinetics was followed by using a quartz crystal microbalance with dissipation monitoring and ellipsometry in terms of mass and thickness growth, respectively. The surface chemical compositions of the obtained polymer brushes were characterized by X‐ray photoelectron spectroscopy. Their mass, thickness, and enzyme‐immobilization ability could be easily tuned by the initiator reaction time, monomer ratio, and polymerization time. The antibacterial activity and stability of the immobilized lysozymes were studied by fluorescent staining and bacteria lysis assay, which revealed that the lysozymes on the copolymer brushes had good stability during storage at 4 °C for up to 30 days.
Facile Synthesis of Multifunctional Germanium Nanoparticles as a Carrier of Quercetin to Achieve Enhanced Biological Activity
Authors: Guo Yan‐Jie , Yang Fen , Zhang Lu , Pi Jiang , Cai Ji‐Ye , Yang Pei‐Hui 
Published: June 2014

AbstractA simple method for preparing quercetin surface‐functionalized germanium nanoparticles (Qu‐GeNPs) with enhanced antioxidant and anticancer activity is reported. Spherical germanium nanoparticles (GeNPs) were capped by quercetin (Qu) with a mean particle size of approximately 33 nm and were characterized by TEM, AFM, UV‐visible absorption spectroscopy, FTIR, and XRD measurements. The in vitro drug release of Qu from the Qu‐GeNPs indicated that Qu could principally be distributed around tumor tissues rather than in the normal section and Qu‐GeNPs were internalized by MCF‐7 cells. Their biological activity test results indicated that these Qu‐GeNPs possessed stronger hydroxyl‐scavenging effects and proliferative inhibition effect on MCF‐7 cancer cells than quercetin, thus suggesting that the strategy to use GeNPs as a carrier of Qu could be an efficient way to achieve enhanced antioxidant and anticancer activity. In addition, Qu‐GeNPs possessed a high apoptotic induction effect in cancer cells, especially in high dosages, and could arrest MCF‐7 cells in the S phase.
Activation of Glycosyl Halides by Halogen Bonding
Authors: Castelli Riccardo , Schindler Severin , Walter Sebastian M. , Kniep Florian , Overkleeft Herman S. , Van der Marel Gijsbert A. , Huber Stefan M. , Codée Jeroen D. C. 
Published: June 2014

AbstractHalogen bonding is the formation of a non‐covalent interaction between an electrophilic halogen substituent and a Lewis base, for instance, a halide. These kinds of relatively weak interactions have found applications in crystal engineering and initial applications in solution‐phase chemistry are starting to appear. We report on the exploration of bis(iodoimidazolium) compounds as halogen‐based Lewis acids in the activation of glycosyl halides. We show that these dicationic halogen‐bond donors can be used to activate glycosyl halides if the carbohydrate core is sufficiently reactive enough. Furthermore, we provide comparison experiments which indicate that the mode of activation is indeed based on halogen bonding. This represents the first glycosylation reaction mediated by a (carbon‐backbone‐based) halogen‐bond donor.
Probing the Shielding Properties of Aptameric Protective Groups
Authors: Bastian Andreas A. , Rodríguez‐Pulido Alberto , Gruszka Agnieszka , Gerasimov Jennifer Y. , Herrmann Andreas 
Published: June 2014

AbstractSite‐specific derivatization of chemically equivalent functional groups has recently been facilitated by the introduction of high‐affinity aptamers as non‐covalent protective groups. More specifically, a series of RNA aptamers have proven to be highly efficient in enhancing the regioselectivity of reactions with the aminoglycoside antibiotic neomycin B, which carries several chemically indistinguishable amino and hydroxy groups. Since small‐molecule targets tend to exhibit multiple modes of binding with a single aptamer, the impact of secondary binding sites on the regioselectivity should be considered. To address this issue, we investigated a series of well‐characterized RNA aptamers that bind neomycin B and propose a mechanism that accounts for the regioselective outcome of these transformations. We further demonstrate that the regioselectivity induced by non‐covalent aptamer protective groups is determined by the number of binding sites, their affinity, and the mode of interaction with the guest molecule.
How the Consideration of Positive Emotions Influences Persuasion: The Differential Effect of Pride Versus Joy
Authors: Karsh Noam , Eyal Tal 
Published: June 2014

ABSTRACTAlthough pride and joy are both positive emotions, we expected their consideration to affect persuasion differently because of the different perspectives (near vs. distant) and level of abstractness they involve, with pride being more abstract than joy. Therefore, we predicted that when the attitude object is construed at a high level rather than a low level, the consideration of pride is likely to promote more persuasion than the consideration of joy. In three studies, we found that the consideration of pride, when featured in the persuasion message (Studies 1a and 1b) or incidentally (Study 2), increased persuasion more than did the consideration of joy, when the persuasion object was temporally distant compared with temporally near (Studies 1a and 1b) or construed as a high‐level category compared with a more concrete individual (Study 2). These findings advance our understanding of the ways in which specific emotions may affect persuasion, beyond valence. Copyright © 2014 John Wiley & Sons, Ltd.