bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Efficient Halogen‐Free Electrolyte for Use in Rechargeable Magnesium Batteries
Authors: Tutusaus Oscar , Mohtadi Rana , Arthur Timothy S. , Mizuno Fuminori , Nelson Emily G. , Sevryugina Yulia V. 
Published: May 2015

AbstractUnlocking the full potential of rechargeable magnesium batteries has been partially hindered by the reliance on chloride‐based complex systems. Despite the high anodic stability of these electrolytes, they are corrosive toward metallic battery components, which reduce their practical electrochemical window. Following on our new design concept involving boron cluster anions, monocarborane CB11H12− produced the first halogen‐free, simple‐type Mg salt that is compatible with Mg metal and displays an oxidative stability surpassing that of ether solvents. Owing to its inertness and non‐corrosive nature, the Mg(CB11H12)2/tetraglyme (MMC/G4) electrolyte system permits standardized methods of high‐voltage cathode testing that uses a typical coin cell. This achievement is a turning point in the research and development of Mg electrolytes that has deep implications on realizing practical rechargeable Mg batteries.
Extraordinary Supercapacitor Performance of a Multicomponent and Mixed‐Valence Oxyhydroxide
Authors: Kang Jianli , Hirata Akihiko , Chen Luyang , Zhu Shengli , Fujita Takeshi , Chen Mingwei 
Published: May 2015

AbstractWe report a novel multicomponent mixed‐valence oxyhydroxide‐based electrode synthesized by electrochemical polarization of a de‐alloyed nanoporous NiCuMn alloy. The multicomponent oxyhydroxide has a high specific capacitance larger than 627 F cm−3 (1097±95 F g−1) at a current density of 0.25 A cm−3, originating from multiple redox reactions. More importantly, the oxyhydroxide electrode possesses an extraordinarily wide working‐potential window of 1.8 V in an aqueous electrolyte, which far exceeds the theoretically stable window of water. The realization of both high specific capacitance and high working‐potential windows gives rise to a high energy density, 51 mWh cm−3, of the multicomponent oxyhydroxide‐based supercapacitor for high‐energy and high‐power applications.
Halogen‐Bond‐Assisted Guest Inclusion in a Synthetic Cavity
Authors: Takezawa Hiroki , Murase Takashi , Resnati Giuseppe , Metrangolo Pierangelo , Fujita Makoto 
Published: May 2015

AbstractThe confined space inside a self‐assembled cage enhanced halogen bonding (XB) between iodoperfluorocarbons (XB donors) and NO3− anions or H2O molecules (XB acceptors), as confirmed by NMR spectroscopy in solution and by X‐ray crystallography in the solid state. The cavity also bound an XB donor–acceptor pair, C6F3I3 and C6H5NMe2, in a selective pairwise fashion.
An Operationally Simple Method for Separating the Rare‐Earth Elements Neodymium and Dysprosium
Authors: Bogart Justin A. , Lippincott Connor A. , Carroll Patrick J. , Schelter Eric J. 
Published: May 2015

AbstractRare‐earth metals are critical components of electronic materials and permanent magnets. Recycling of consumer materials is a promising new source of rare earths. To incentivize recycling there is a clear need for simple methods for targeted separations of mixtures of rare‐earth metal salts. Metal complexes of a tripodal nitroxide ligand [{(2‐tBuNO)C6H4CH2}3N]3− (TriNOx3−), feature a size‐sensitive aperture formed of its three η2‐(N,O) ligand arms. Exposure of metal cations in the aperture induces a self‐associative equilibrium comprising [M(TriNOx)thf]/ [M(TriNOx)]2 (M=rare‐earth metal). Differences in the equilibrium constants (Keq) for early and late metals enables simple Nd/Dy separations through leaching with a separation ratio SNd/Dy=359.
Brønsted Acid Catalyzed Asymmetric Hydroamination of Alkenes: Synthesis of Pyrrolidines Bearing a Tetrasubstituted Carbon Stereocenter
Authors: Lin Jin‐Shun , Yu Peng , Huang Lin , Zhang Pan , Tan Bin , Liu Xin‐Yuan 
Published: May 2015

AbstractThe first highly enantioselective Brønsted acid catalyzed intramolecular hydroamination of alkenes enables the efficient construction of a series of chiral (spirocyclic) pyrrolidines with an α‐tetrasubstituted carbon stereocenter with excellent functional group tolerance. A unique feature of this strategy is the use of a thiourea group acting as both the activating and the directing group through cooperative multiple hydrogen bonding with a Brønsted acid and the double bond. The utility of this method is highlighted by the facile construction of chiral synthetic intermediates and important structural motifs that are widely found in organic synthesis.
Chemical Synthesis of O‐Glycosylated Human Interleukin‐2 by the Reverse Polarity Protection Strategy
Authors: Asahina Yuya , Komiya Shinobu , Ohagi Ami , Fujimoto Rina , Tamagaki Hiroko , Nakagawa Katsuhiro , Sato Takashi , Akira Shizuo , Takao Toshifumi , Ishii Akira , Nakahara Yoshiaki , Hojo Hironobu 
Published: May 2015

AbstractThe chemical synthesis of human interleukin‐2 (IL‐2) , having a core 1 sugar, by a ligation method is reported. Although IL‐2 is a globular glycoprotein, its C‐terminal region, in particular (99‐133), is extremely insoluble when synthesized by solid‐phase method. To overcome this problem, the side‐chain carboxylic acid of the Glu residues was protected by a picolyl ester, thus reversing its polarity from negative to positive. This reverse polarity protection significantly increased the isoelectric point of the peptide segment and made it positive under acidic conditions and facilitated the purification. An efficient method to prepare the prolyl peptide thioester required for the synthesis of the (28‐65) segment was also developed. These efforts resulted in the total synthesis of the glycosylated IL‐2 having full biological activity.
Controlling the Structure and Length of Self‐Synthesizing Supramolecular Polymers through Nucleated Growth and Disassembly
Authors: Pal Asish , Malakoutikhah Morteza , Leonetti Giulia , Tezcan Meniz , Colomb‐Delsuc Mathieu , Nguyen Van Duc , van der Gucht Jasper , Otto Sijbren 
Published: May 2015

AbstractDirecting self‐assembly processes out‐of‐equilibrium to yield kinetically trapped materials with well‐defined dimensions remains a considerable challenge. Kinetically controlled assembly of self‐synthesizing peptide‐functionalized macrocycles through a nucleation–growth mechanism is reported. Spontaneous fiber formation in this system is effectively shut down as most of the material is diverted into metastable non‐assembling trimeric and tetrameric macrocycles. However, upon adding seeds to this mixture, well‐defined fibers with controllable lengths and narrow polydispersities are obtained. This seeded growth strategy also allows access to supramolecular triblock copolymers. The resulting noncovalent assemblies can be further stabilized through covalent capture. Taken together, these results show that self‐synthesizing materials, through their interplay between dynamic covalent bonds and noncovalent interactions, are uniquely suited for out‐of‐equilibrium self‐assembly.
Copper‐Catalyzed Oxy‐Alkenylation of Homoallylic Alcohols to Generate Functional syn‐1,3‐Diol Derivatives
Authors: Holt Dean , Gaunt Matthew J. 
Published: May 2015

AbstractA novel method for the synthesis of a wide range of functionalized 1,3‐diol derivatives is reported. Employing a copper‐catalyzed oxy‐alkenylation strategy, a range of readily available, substituted homoallylic alcohol derivatives and alkenyl(aryl) iodonium salts combine to form syn‐1,3‐carbonates in excellent yield and with high selectivity. Furthermore, the products formed are amenable to an iterative reaction sequence, thus affording highly complex polyketide‐like fragments.
Multistimuli‐Responsive, Moldable Supramolecular Hydrogels Cross‐Linked by Ultrafast Complexation of Metal Ions and Biopolymers
Authors: Sun Zhifang , Lv Fucong , Cao Lujie , Liu Lin , Zhang Yi , Lu Zhouguang 
Published: May 2015

AbstractA new type of multistimuli‐responsive hydrogels cross‐linked by metal ions and biopolymers is reported. By mixing the biopolymer chitosan (CS) with a variety of metal ions at the appropriate pH values, we obtained a series of transparent and stable hydrogels within a few seconds through supramolecular complexation. In particular, the CS–Ag hydrogel was chosen as the model and the gelation mechanism was revealed by various measurements. It was found that the facile association of Ag+ ions with amino and hydroxy groups in CS chains promoted rapid gel‐network formation. Interestingly, the CS–Ag hydrogel exhibits sharp phase transitions in response to multiple external stimuli, including pH value, chemical redox reactions, cations, anions, and neutral species. Furthermore, this soft matter showed a remarkable moldability to form shape‐persistent, free‐standing objects by a fast in situ gelation procedure.
Gold‐Catalyzed Cascade Cyclization of 2‐Alkynyl‐N‐Propargylanilines by Rearrangement of a Propargyl Group
Authors: Tokimizu Yusuke , Oishi Shinya , Fujii Nobutaka , Ohno Hiroaki 
Published: May 2015

AbstractGold catalysis enables direct construction of tetracyclic fused indolines through the migration of a propargyl substituent from an aniline nitrogen atom to the C3‐position of an indole from 2‐alkynyl‐N‐propargylanilines. This reaction provides rapid access to fused three‐dimensional indolines in a single operation with the formation of four bonds and three rings.
Dual Hypervalent Iodine(III) Reagents and Photoredox Catalysis Enable Decarboxylative Ynonylation under Mild Conditions
Authors: Huang Hanchu , Zhang Guojin , Chen Yiyun 
Published: May 2015

AbstractA combination of hypervalent iodine(III) reagents (HIR) and photoredox catalysis with visible light has enabled chemoselective decarboxylative ynonylation to construct ynones, ynamides, and ynoates. This ynonylation occurs effectively under mild reaction conditions at room temperature and on substrates with various sensitive and reactive functional groups. The reaction represents the first HIR/photoredox dual catalysis to form acyl radicals from α‐ketoacids, followed by an unprecedented acyl radical addition to HIR‐bound alkynes. Its efficient construction of an mGlu5 receptor inhibitor under neutral aqueous conditions suggests future visible‐light‐induced biological applications.
Tetrabenzoperipentacene: Stable Five‐Electron Donating Ability and a Discrete Triple‐Layered β‐Graphite Form in the Solid State
Authors: Matsumoto Akinobu , Suzuki Mitsuharu , Kuzuhara Daiki , Hayashi Hironobu , Aratani Naoki , Yamada Hiroko 
Published: May 2015

AbstractAn oxidative ring‐closure reaction of a tetranaphthylpyrene derivative led to the synthesis of a 56 all‐carbon conjugated tetrabenzoperipentacene. In the single‐crystal X‐ray structure, three molecules make a triple‐layered cluster by π‐stacking, wherein each layer rotates by 120°, and is thus considered a petit β‐graphite. As for the optical properties, the Stokes shift is extremely small (10 cm−1), thus indicating its remarkably rigid framework. The tetrabenzoperipentacene exhibits reversible five‐electron oxidation waves in cyclic voltammetry, and is regarded as a counterpart to the fullerene C60 in terms of stable multicharge‐storage nanocarbon materials.
A Triphenylamine with Two Phenoxy Radicals Having Unusual Bonding Patterns and a Closed‐Shell Electronic State
Authors: Sakamaki Daisuke , Yano Soichiro , Kobashi Toshiyuki , Seki Shu , Kurahashi Takuya , Matsubara Seijiro , Ito Akihiro , Tanaka Kazuyoshi 
Published: May 2015

AbstractReported herein is the structure and the electronic properties of a novel triphenylamine derivative having two phenoxy radicals appended to the amino nitrogen atom. X‐ray single crystal analysis and the magnetic resonance measurements demonstrates the unexpected closed‐shell electronic structure, even at room temperature, of the molecule and two unusual CN bonds with multiple‐bond character. The theoretical calculations support the experimentally determined molecular geometry with the closed‐shell electronic structure, and predicted a small HOMO–LUMO gap originating from the nonbonding character of the HOMO. The optical and electrochemical measurements show that the molecule has a remarkably small HOMO–LUMO gap compared with its triphenylamine precursor.
Size‐Dependent Ligand Layer Dynamics in Semiconductor Nanocrystals Probed by Anisotropy Measurements
Authors: Hadar Ido , Abir Tsafrir , Halivni Shira , Faust Adam , Banin Uri 
Published: May 2015

AbstractColloidal semiconductor nanocrystals (NC) have reached a high level of synthetic control allowing the tuning of their properties, and their use in various applications. However, the surface of NCs and in particular their size‐dependent capping organic ligand behavior, which play an important role in the NC synthesis, dispersibility, and optoelectronic properties, is still not well understood. We study the size‐dependent properties of the ligand shell on the surface of NCs, by embedding surface bound dyes as a probe within the ligand shell. The reorientation times for these dyes show a linear dependence on the NC surface curvature indicating size‐dependent change in viscosity, which is related to a change in the density of the ligand layer because of the geometry of the surface, a unique feature of NCs. Understanding the properties of the ligand shell will allow rational design of the surface to achieve the desired properties, providing an additional important knob for tuning their functionality.
Attenuated Organomagnesium Activation of White Phosphorus
Authors: Arrowsmith Merle , Hill Michael S. , Johnson Andrew L. , Kociok‐Köhn Gabriele , Mahon Mary F. 
Published: May 2015

AbstractSequential reactions between a 2,6‐diisopropylphenyl‐substituted β‐diketiminato magnesium n‐butyl derivative and P4 allow the highly discriminating synthesis of unusual [nBu2P4]2− and [nBu2P8]2− cluster dianions.
Rapid Cationization of Gold Nanoparticles by Two‐Step Phase Transfer
Authors: Hassinen Jukka , Liljeström Ville , Kostiainen Mauri A. , Ras Robin H. A. 
Published: May 2015

AbstractCationic gold nanoparticles offer intriguing opportunities as drug carriers and building blocks for self‐assembled systems. Despite major progress on gold nanoparticle research in general, the synthesis of cationic gold particles larger than 5 nm remains a major challenge, although these species would give a significantly larger plasmonic response compared to smaller cationic gold nanoparticles. Herein we present the first reported synthesis of cationic gold nanoparticles with tunable sizes between 8–20 nm, prepared by a rapid two‐step phase‐transfer protocol starting from simple citrate‐capped particles. These cationic particles form ordered self‐assembled structures with negatively charged biological components through electrostatic interactions.
Construction of an Internally B3N3‐Doped Nanographene Molecule
Authors: Krieg Matthias , Reicherter Florian , Haiss Peter , Ströbele Markus , Eichele Klaus , Treanor Michael‐John , Schaub Renald , Bettinger Holger F. 
Published: May 2015

AbstractThe synthesis of a hexa‐peri‐hexabenzocoronene (HBC) with a central borazine core is described. The solid‐state structure of this BN‐doped HBC (BN‐HBC) is isotypic with that of the parent HBC. Scanning tunneling microscopy shows that BN‐HBC lies flat on Au(111) in a two‐dimensional pattern.
An Isolable Radical Anion of an Organosilicon Cluster Containing Only σ Bonds
Authors: Otsuka Kyohei , Matsumoto Naozumi , Ishida Shintaro , Kyushin Soichiro 
Published: May 2015

AbstractThe radical anion of octa‐tert‐butyloctasilacubane was generated and isolated. The EPR spectrum showed the satellites due to the tertiary 13C nuclei of the eight tert‐butyl groups. The X‐ray crystallographic analysis showed that the SiSi bonds are shortened and the SiC bonds are elongated compared with those of octa‐tert‐butyloctasilacubane. These results are well explained by the distribution of an unpaired electron in the singly occupied molecular orbital (SOMO).
A Catalyst Platform for Unique Cationic (Co)Polymerization in Aqueous Emulsion
Authors: Vasilenko Irina V. , Yeong Hui Yee , Delgado Marco , Ouardad Samira , Peruch Frédéric , Voit Brigitte , Ganachaud François , Kostjuk Sergei V. 
Published: May 2015

AbstractSodium dodecyl benzene sulfonate (DBSNa) surfactants, with a polydisperse and hyperbranched structure, combined with different rare earth metal salts generate highly water‐dispersible Lewis acid surfactant combined catalysts (LASCs). This platform of new complexes promotes fast, efficient cationic polymerization of industrially relevant monomers in direct emulsion at moderate temperature. The process described here does not require high shearing, long polymerization time, or large catalyst content. It allows the reproducible generation of high‐molar‐mass homopolymers of pMOS, styrene, and isoprene, as well as random or multiblock copolymers of the latter two, in a simple and straightforward one‐pot reaction.
Size of Gold Nanoparticles Driving Selective Amide Synthesis through Aerobic Condensation of Aldehydes and Amines
Authors: Miyamura Hiroyuki , Min Hyemin , Soulé Jean‐François , Kobayashi Shū 
Published: May 2015

AbstractMetal nanoparticles (NPs) have attracted much attention in many fields due to their intrinsic characteristics. It is generally accepted that smaller NPs (1.5–3 nm) are more active than larger NPs, and reverse cases are very rare. We report here the direct aerobic oxidative amide synthesis from aldehydes and amines catalyzed by polymer‐incarcerated gold (Au) NPs. A unique correlation between imine/amide selectivity and size of NPs was discovered; Au‐NPs of medium size (4.5–11 nm) were found to be optimal. High yields were obtained with a broad range of substrates, including primary amines. Au‐NPs of medium size could be recovered and reused several times without loss of activity, and they showed good activity and selectivity in amide formation from alcohols and amines.
Iron Carbide Nanoparticles Encapsulated in Mesoporous Fe‐N‐Doped Carbon Nanofibers for Efficient Electrocatalysis
Authors: Wu Zhen‐Yu , Xu Xing‐Xing , Hu Bi‐Cheng , Liang Hai‐Wei , Lin Yue , Chen Li‐Feng , Yu Shu‐Hong 
Published: May 2015

AbstractExploring low‐cost and high‐performance nonprecious metal catalysts (NPMCs) for oxygen reduction reaction (ORR) in fuel cells and metal–air batteries is crucial for the commercialization of these energy conversion and storage devices. Here we report a novel NPMC consisting of Fe3C nanoparticles encapsulated in mesoporous Fe‐N‐doped carbon nanofibers, which is synthesized by a cost‐effective method using carbonaceous nanofibers, pyrrole, and FeCl3 as precursors. The electrocatalyst exhibits outstanding ORR activity (onset potential of −0.02 V and half‐wave potential of −0.140 V) closely comparable to the state‐of‐the‐art Pt/C catalyst in alkaline media, and good ORR activity in acidic media, which is among the highest reported activities of NPMCs.
Computer‐Aided Design of Ionic Liquids as CO2 Absorbents
Authors: Firaha Dzmitry S. , Hollóczki Oldamur , Kirchner Barbara 
Published: May 2015

AbstractIonic liquids (ILs), vary strongly in their interaction with CO2. We suggest simple theoretical approach to predict the CO2 absorption behavior of ILs. Strong interaction of the CO2 with the IL anions corresponds to chemical absorption whereas weak interaction indicates physical absorption. A predictive estimate with a clear distinction between physical and chemical absorption can be simply obtained according to geometries optimized in the presence of a solvation model instead of optimizing it only in gas phase as has been done to date. The resulting Gibbs free energies compare very well with experimental values and the energies were correlated with experimental capacities. Promising anions, for ionic liquids with reversible CO2 absorption properties can be defined by a reaction Gibbs free energy of absorption in the range of −30 to 16 kJ mol−1.
Frenkel‐Defect‐Mediated Chemical Ordering Transition in a Li–Mn–Ni Spinel Oxide
Authors: Ryoo Hyewon , Bae Hyung Bin , Kim Young‐Min , Kim Jin‐Gyu , Lee Seongsu , Chung Sung‐Yoon 
Published: May 2015

AbstractUsing spinel‐type Li(Mn1.5Ni0.5)O4 with two different cations, Mn and Ni, in the oxygen octahedra as a model system, we show that a cation ordering transition takes place through the formation of Frenkel‐type point defects. A series of experimental results based on atomic‐scale observations and in situ powder diffractions along with ab initio calculations consistently support such defect‐mediated transition behavior. In addition to providing a precise suggestion of the intermediate transient states and the resulting kinetic pathway during the transition between two phases, our findings emphasize the significant role of point defects in ordering transformation of complex oxides.
Epigenetic Genome Mining of an Endophytic Fungus Leads to the Pleiotropic Biosynthesis of Natural Products
Authors: Mao Xu‐Ming , Xu Wei , Li Dehai , Yin Wen‐Bing , Chooi Yit‐Heng , Li Yong‐Quan , Tang Yi , Hu Youcai 
Published: May 2015

AbstractThe small‐molecule biosynthetic potential of most filamentous fungi has remained largely unexplored and represents an attractive source for the discovery of new compounds. Genome sequencing of Calcarisporium arbuscula, a mushroom‐endophytic fungus, revealed 68 core genes that are involved in natural product biosynthesis. This is in sharp contrast to the predominant production of the ATPase inhibitors aurovertin B and D in the wild‐type fungus. Inactivation of a histone H3 deacetylase led to pleiotropic activation and overexpression of more than 75 % of the biosynthetic genes. Sampling of the overproduced compounds led to the isolation of ten compounds of which four contained new structures, including the cyclic peptides arbumycin and arbumelin, the diterpenoid arbuscullic acid A, and the meroterpenoid arbuscullic acid B. Such epigenetic modifications therefore provide a rapid and global approach to mine the chemical diversity of endophytic fungi.
The Donor‐Base‐Free Aggregation of Lithium Diisopropyl Amide in Hydrocarbons Revealed by a DOSY Method
Authors: Neufeld Roman , John Michael , Stalke Dietmar 
Published: May 2015

AbstractLithium diisopropyl amide (LDA) is a very prominent reagent that plays a key role in organic synthesis, serving as a base par excellence for a broad range of deprotonation reactions. However, the state of aggregation in solution in the absence of donor bases was unclear. In this paper we solved this problem by employing DOSY NMR experiments based on a newly elaborated external calibration curve (ECC) approach with normalized diffusion coefficients.
A Photoelectrochemical Solar Cell Consisting of a Cadmium Sulfide Photoanode and a Ruthenium–2,2′‐Bipyridine Redox Shuttle in a Non‐aqueous Electrolyte
Authors: Kageshima Yosuke , Kumagai Hiromu , Minegishi Tsutomu , Kubota Jun , Domen Kazunari 
Published: May 2015

AbstractA photoelectrochemical (PEC) cell consisting of an n‐type CdS single‐crystal electrode and a Pt counter electrode with the ruthenium–2,2′‐bipyridine complex [Ru(bpy)3]2+/3+ as the redox shuttle in a non‐aqueous electrolyte was studied to obtain a higher open‐circuit voltage (VOC) than the onset voltage for water splitting. A VOC of 1.48 V and a short‐circuit current (ISC) of 3.88 mA cm−2 were obtained under irradiation by a 300 W Xe lamp with 420–800 nm visible light. This relatively high voltage was presumably due to the difference between the Fermi level of photo‐irradiated n‐type CdS and the redox potential of the Ru complex at the Pt electrode. The smooth redox reaction of the Ru complex with one‐electron transfer was thought to have contributed to the high VOC and ISC. The obtained VOC was more than the onset voltage of water electrolysis for hydrogen and oxygen generation, suggesting prospects for application in water electrolysis.