bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterogene molekulare Systeme für eine photokatalytische CO2‐Reduktion mit Wasseroxidation
Authors: Liu Xiao , Inagaki Shinji , Gong Jinlong 
Published: October 2016

AbstractDie künstliche Photosynthese, mit einer CO2‐Reduktion zu Chemikalien und Brennstoffen und einer Wasseroxidation unter Verwendung von Sonnenlicht als Energiequelle, ahmt die natürliche Photosynthese in Grünpflanzen nach. Es ist davon auszugehen, dass diese Technologie eine bedeutende Rolle in unserer zukünftigen Energieversorgung haben wird. Aufgrund der hohen Quantenausbeute und der einfachen Manipulierbarkeit bieten heterogene molekulare Photosysteme auf der Basis von Metallkomplexen eine vielversprechende Plattform für eine effiziente Umwandlung von Solarenergie. Dieser Aufsatz beschreibt jüngste Entwicklungen bei der Heterogenisierung solcher Photokatalysatoren. Wir stellen aktuelle Ansätze vor, mit denen die Nachteile einer geringen Beständigkeit und einer unbequemen praktischen Anwendung von homogenen molekularen Systemen überwunden werden sollen, und wir diskutieren die Kopplung der photokatalytischen CO2‐Reduktion mit der Wasseroxidation durch molekulare Vorrichtungen.
Muonium Chemistry at Diiron Subsite Analogues of [FeFe]‐Hydrogenase
Authors: Wright Joseph A. , Peck Jamie N. T. , Cottrell Stephen P. , Jablonskytė Aušra , Oganesyan Vasily S. , Pickett Christopher J. , Jayasooriya Upali A. 
Published: October 2016

AbstractThe chemistry of metal hydrides is implicated in a range of catalytic processes at metal centers. Gaining insight into the formation of such sites by protonation and/or electronation is therefore of significant value in fully exploiting the potential of such systems. Here, we show that the muonium radical (Mu.), used as a low isotopic mass analogue of hydrogen, can be exploited to probe the early stages of hydride formation at metal centers. Mu. undergoes the same chemical reactions as H. and can be directly observed due to its short lifetime (in the microseconds) and unique breakdown signature. By implanting Mu. into three models of the [FeFe]‐hydrogenase active site we have been able to detect key muoniated intermediates of direct relevance to the hydride chemistry of these systems.
Concise, Enantioselective, and Versatile Synthesis of (−)‐Englerin A Based on a Platinum‐Catalyzed [4C+3C] Cycloaddition of Allenedienes
Authors: Nelson Ronald , Gulías Moisés , Mascareñas José L. , López Fernando 
Published: October 2016

AbstractA practical synthesis of (−)‐englerin A was accomplished in 17 steps and 11 % global yield from commercially available achiral precursors. The key step consists of a platinum‐catalyzed [4C+3C] allenediene cycloaddition that directly delivers the trans‐fused guaiane skeleton with complete diastereoselectivity. The high enantioselectivity (99 % ee) stems from an asymmetric ruthenium‐catalyzed transfer hydrogenation of a readily assembled diene–ynone. The synthesis also features a highly stereoselective oxygenation, and a late‐stage cuprate alkylation that enables the preparation of previously inaccessible structural analogues.
Highly Selective Construction of Seven‐Membered Carbocycles by Olefin‐Assisted Palladium‐Catalyzed Oxidative Carbocyclization–Alkoxycarbonylation of Bisallenes
Authors: Zhu Can , Yang Bin , Qiu Youai , Bäckvall Jan‐E. 
Published: October 2016

AbstractAn olefin‐assisted palladium‐catalyzed oxidative carbocyclization–alkoxycarbonylation of bisallenes to afford seven‐membered carbocycles has been established. This dehydrogenative coupling reaction showed excellent substrate scope and functional group compatibility. The reaction exhibited high chemo‐ and regioselectivity, and ester 3 was the only product obtained. The olefin unit has been proven to be indispensable during the reaction. Moreover, intramolecular oxidative coupling suggests that the reaction proceeds via a (π‐allyl)palladium intermediate.
A Cascade Strategy Enables a Total Synthesis of (±)‐Morphine
Authors: Chu Shuyu , Münster Niels , Balan Tudor , Smith Martin D. 
Published: October 2016

AbstractMorphine has been a target for synthetic chemists since Robinson proposed its correct structure in 1925, resulting in a large number of total syntheses of morphine alkaloids. Here we report a total synthesis of (±)‐morphine that employs two key strategic cyclizations: 1) a diastereoselective light‐mediated cyclization of an O‐arylated butyrolactone to form a tricyclic cis‐fused benzofuran and 2) a cascade ene–yne–ene ring closing metathesis to forge the tetracyclic morphine core. This approach enables a short and stereoselective synthesis of morphine in an overall yield of 6.6 %.
Isolation of a Star‐Shaped Uranium(V/VI) Cluster from the Anaerobic Photochemical Reduction of Uranyl(VI)
Authors: Chatelain Lucile , White Sarah , Scopelliti Rosario , Mazzanti Marinella 
Published: October 2016

AbstractActinide oxo clusters are an important class of compounds due to their impact on actinide migration in the environment. The photolytic reduction of uranyl(VI) has potential application in catalysis and spent nuclear fuel reprocessing, but the intermediate species involved in this reduction have not yet been elucidated. Here we show that the photolysis of partially hydrated uranyl(VI) in anaerobic conditions leads to the reduction of uranyl(VI), and to the incorporation of the resulting UV species into the stable mixed‐valent star‐shaped UVI/UV oxo cluster [U(UO2)5(μ3‐O)5(PhCOO)5(Py)7] (1). This cluster is only the second example of a UVI/UV cluster and the first one associating uranyl groups to a non‐uranyl(V) center. The UV center in 1 is stable, while the reaction of uranyl(V) iodide with potassium benzoate leads to immediate disproportionation and formation of the U12IVU4VO24 cluster {[K(Py)2]2[K(Py)]2[U16O24(PhCOO)24(Py)2]} (5).
Heterogeneous Molecular Systems for Photocatalytic CO2 Reduction with Water Oxidation
Authors: Liu Xiao , Inagaki Shinji , Gong Jinlong 
Published: October 2016

AbstractArtificial photosynthesis—reduction of CO2 into chemicals and fuels with water oxidation in the presence of sunlight as the energy source—mimics natural photosynthesis in green plants, and is considered to have a significant part to play in future energy supply and protection of our environment. The high quantum efficiency and easy manipulation of heterogeneous molecular photosystems based on metal complexes enables them to act as promising platforms to achieve efficient conversion of solar energy. This Review describes recent developments in the heterogenization of such photocatalysts. The latest state‐of‐the‐art approaches to overcome the drawbacks of low durability and inconvenient practical application in homogeneous molecular systems are presented. The coupling of photocatalytic CO2 reduction with water oxidation through molecular devices to mimic natural photosynthesis is also discussed.
Phosphine‐Stabilized Borylenes and Boryl Anions as Ligands? Redox Reactivity in Boron‐Based Pincer Complexes
Authors: Vondung Lisa , Frank Nicolas , Fritz Maximilian , Alig Lukas , Langer Robert 
Published: October 2016

AbstractStabilized borylenes (L2BH:) with weakly π‐accepting substituents L, such as phosphines, were previously believed to be unstable. In the current manuscript, we describe a series of complexes formally containing a phosphine‐stabilized borylene or boryl anion. In contrast to common trivalent boron compounds, the boron‐based ligands in this study act as electron‐donating ligands. The reported iron hydride complexes exhibit a unique reactivity pattern, undergoing a reversible B−H reductive elimination concomitant with oxidation of the boron(I) center.
Nanofibrillar Stimulus‐Responsive Cholesteric Microgels with Catalytic Properties
Authors: Cho Sangho , Li Yunfeng , Seo Minseok , Kumacheva Eugenia 
Published: October 2016

AbstractWe report composite stimulus‐responsive cholesteric catalytically active microgels derived from filamentous supramolecular building blocks: cellulose nanocrystals (CNCs). The variation in the microgel dimensions and pitch in response to the change in ambient conditions was governed by the polymer component. The cholesteric morphology of the microgels resulted from the self‐organization of CNCs in spherical confinement. The microgels exhibited excellent structural integrity and functioned as microreactors in catalytic hydrolysis reactions and in the synthesis of metal nanoparticles. Because of these collective properties, the reported microgels show much promise for application in the design of functional responsive materials.
Thermally Induced Intra‐Carboxyl Proton Shuttle in a Molecular Rack‐and‐Pinion Cascade Achieving Macroscopic Crystal Deformation
Authors: Huang You‐Gui , Shiota Yoshihito , Su Sheng‐Qun , Wu Shu‐Qi , Yao Zi‐Shuo , Li Guo‐Ling , Kanegawa Shinji , Kang Soonchul , Kamachi Takashi , Yoshizawa Kazunari , Ariga Katsuhiko , Sato Osamu 
Published: October 2016

AbstractProton transport via dynamic molecules is ubiquitous in chemistry and biology. However, its use as a switching mechanism for properties in functional molecular assemblies is far less common. In this study, we demonstrate how an intra‐carboxyl proton shuttle can be generated in a molecular assembly akin to a rack‐and‐pinion cascade via a thermally induced single‐crystal‐to‐single‐crystal phase transition. In a triply interpenetrated supramolecular organic framework (SOF), a 4,4′‐azopyridine (azpy) molecule connects to two biphenyl‐3,3′,5,5′‐tetracarboxylic acid (H4BPTC) molecules to form a functional molecular system with switchable mechanical properties. A temperature change reversibly triggers a molecular movement akin to a rack‐and‐pinion cascade, which mainly involves 1) an intra‐carboxyl proton shuttle coupled with tilting of the azo molecules and azo pedal motion and 2) H4BPTC translation. Moreover, both the molecular motions are collective, and being propagated across the entire framework, leading to a macroscopic crystal expansion and contraction.
Trapping σ‐Alkyl–Palladium(II) Intermediates with Arynes Encompassing Intramolecular C−H Activation: Spirobiaryls through Pd‐Catalyzed Cascade Reactions
Authors: Pérez‐Gómez Marta , García‐López José‐Antonio 
Published: October 2016

AbstractA palladium‐catalyzed cascade reaction based on the trapping of transient alkyl–PdII intermediates with arynes encompassing a C−H activation step has been developed. This synthetic pathway gives rise to hetero‐spirocyclic scaffolds containing a biaryl motif, and opens up new synthetic strategies in the design of cascade reactions since it gathers several aspects of Pd chemistry, i.e., intra‐ and intermolecular carbopalladation of unsaturated species, C−H activation and C−C coupling processes.
Sulfonium Ylides by (3+2) Cycloaddition of Arynes with Vinyl Sulfides: Stereoselective Synthesis of Highly Substituted Alkenes
Authors: Li Yuanming , Mück‐Lichtenfeld Christian , Studer Armido 
Published: October 2016

AbstractThe reaction of in situ generated arynes with vinyl sulfides provides benzannulated sulfonium ylides in a (3+2) cycloaddition. Trapping of the intermediate ylides with electrophiles (proton transfer or a second aryne addition) and subsequent β‐elimination give rise to di‐, tri‐, or tetrasubstituted alkenes with high stereoselectivity. Experimental studies and DFT calculations provide insight into the mechanisms of these cascade reactions.
Short‐Range Order of Methylammonium and Persistence of Distortion at the Local Scale in MAPbBr3 Hybrid Perovskite
Authors: Page Katharine , Siewenie Joan E. , Quadrelli Paolo , Malavasi Lorenzo 
Published: October 2016

AbstractShort‐range investigation by means of variable‐temperature neutron total scattering and pair distribution function analysis revealed that the local environment around the methylammonium (MA) cation in MAPbBr3 hybrid perovskite is maintained through the different phase transitions observed as a function of temperature. In addition, the orthorhombic distortion of the lattice is present at any temperature. Local structure around MA changes from static to configurationally averaged or dynamic with temperature but the local structure of the low‐temperature orthorhombic phase is preserved.
Asymmetric Anion–π Catalysis on Perylenediimides
Authors: Wang Chao , Miros François N. , Mareda Jiri , Sakai Naomi , Matile Stefan 
Published: October 2016

AbstractAnion–π catalysis, that is the stabilization of anionic transition states on π‐acidic aromatic surfaces, has so far been developed with naphthalenediimides (NDIs). This report introduces perylenediimides (PDIs) to anion–π catalysis. The quadrupole moment of PDIs (+23.2 B) is found to exceed that of NDIs and reach new records with acceptors in the core (+70.9 B), and their larger surface provides space to better accommodate chemical transformations. Unlike NDIs, the activity of PDI catalysts for enolate and enamine addition is determined by the twist of their π surface rather than their reducibility. These results, further strengthened by nitrate inhibition and circular dichroism spectroscopy, support an understanding of anion–π interactions centered around quadrupole moments, i.e., electrostatic contributions, rather than redox potentials and charge transfer. The large PDI surfaces provide access to the highest enantioselectivities observed so far in anion–π catalysis (96 % ee).
A Migratory Ether Formation Route to Medium‐Sized Sugar Mimetics
Authors: Jiang Hao , Xu Li‐Ping , Fang Yan , Zhang Zhen‐Xing , Yang Zhen , Huang Yong 
Published: October 2016

AbstractPolyol‐substituted cyclic ethers are fundamental building blocks of biomolecules. The position and stereochemistry of multiple hydroxy substituents of cyclic ethers play a central role in their biological function. Current methods for the synthesis of such structures are limited to “naked” ring products with no or few substituents. Here we describe a general route to medium‐sized polyol cyclic ethers using a migratory ether formation strategy. In contrast to the common pathway of direct opening of epoxides, Me3Al was found to promote an unprecedented ether addition reaction, opening a neighboring epoxide. The resulting oxonium intermediate triggers a 1,3‐methyl shift to yield 2‐deoxyribital products. When the hemiacetal auxiliary is a monosaccharide, the sugar ring is expanded by four atoms to give the corresponding 9‐ to 11‐membered analogues. This method provides an entry into the untapped chemical space of medium‐sized sugar mimetics.
The Binary Group 4 Azides [PPh4]2[Zr(N3)6] and [PPh4]2[Hf(N3)6]
Authors: Deokar Piyush , Vasiliu Monica , Dixon David A. , Christe Karl O. , Haiges Ralf 
Published: October 2016

AbstractThe binary zirconium and hafnium polyazides [PPh4]2[M(N3)6] (M=Zr, Hf) were obtained in near quantitative yields from the corresponding metal fluorides MF4 by fluoride–azide exchange reactions with Me3SiN3 in the presence of two equivalents of [PPh4][N3]. The novel polyazido compounds were characterized by their vibrational spectra and their X‐ray crystal structures. Both anion structures provide experimental evidence for near‐linear M‐N‐N coordination of metal azides. The species [M(N3)4], [M(N3)5]− and [M(N3)6]2− (M=Ti, Zr, Hf) were studied by quantum chemical calculations at the electronic structure density functional theory and MP2 levels.
Synthesis of a self‐emulsifiable waterborne epoxy curing agent based on glycidyl tertiary carboxylic ester and its cure characteristics
Authors: Zhang Kai , Huang Chunbao , Fang Qiujie , Lu Qin 
Published: October 2016

ABSTRACTA novel self‐emulsifiable waterborne amine‐terminated curing agent for epoxy resin based on glycidyl tertiary carboxylic ester (GTCE) was synthesized through three steps of addition reaction, capping reaction, and salification reaction of triethylene tetramine (TETA) and liquid epoxy resin (E‐44). The curing agent with good emulsifying and curing properties was gradually obtained under condition of the molar ratio of TETA: E‐44 as 2.2: 1 at 65 °C for 4 h, 100% primary amine capped with GTCE at 70 °C for 3 h, and 20% salifiable rate with glacial acetic acid. The curing agent was characterized by Fourier transform‐infrared spectroscopy (FT‐IR). The curing behavior of the E‐44/GTCE‐TETA‐E‐44 system was studied with differential scanning calorimetry (DSC) and FT‐IR. Results showed that the optimal mass ratio for E‐44/GTCE‐TETA‐E‐44 system was 3 to 1, and the curing agent showed a relatively lower curing temperature. The cured film prepared by the self‐emulsifiable curing agent and epoxy resin under the optimal mass ratio displayed good thermal property, hardness, toughness, adhesion, and corrosion resistance. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44246.
Bioanalytical method for the estimation of co‐administered esomeprazole, leflunomide and ibuprofen in human plasma and in pharmaceutical dosage forms using micellar liquid chromatography
Authors: Talaat Wael 
Published: October 2016

AbstractThe present study represents a connection between basic science and clinical applied science through providing a bioanalytical method for the analysis of certain co‐administered drugs used for the treatment of rheumatoid arthritis. The studied drugs are esomeprazole, leflunomide and ibuprofen. The proposed bioanalytical method is a simple reversed phase high performance liquid chromatographic method using micellar mobile phase. The method is conducted using a Shim‐pack VP‐ODS (150 mm × 4.6 mm ID) stainless steel column at ambient temperature with ultraviolet detection at 285 nm. The micellar mobile phase consisted of 0.1 m sodium dodecyl sulfate, 10% n‐propanol, 0.3% triethylamine in 0.02 m orthophosphoric acid (pH 3.5) and is pumped at a flow rate of 1.0 mL/min. The calibration curve was rectilinear over the concentration range of 0.1–5.0, 0.5–10.0 and 1.0–20.0 μg/mL for esomeprazole, leflunomide and ibuprofen respectively. The proposed method was successfully applied to the analysis of these drugs in dosage forms. The method is extended to the in‐vitro, in‐vivo determination of these drugs in spiked and real human plasma samples.
Is there a role for IGF‐1 in the development of second primary cancers?
Authors: Shanmugalingam Thurkaa , Bosco Cecilia , Ridley Anne J. , Van Hemelrijck Mieke 
Published: October 2016

AbstractCancer survival rates are increasing, and as a result, more cancer survivors are exposed to the risk of developing a second primary cancer (SPC). It has been hypothesized that one of the underlying mechanisms for this risk could be mediated by variations in insulin‐like growth factor‐1 (IGF‐1). This review summarizes the current epidemiological evidence to identify whether IGF‐1 plays a role in the development of SPCs. IGF‐1 is known to promote cancer development by inhibiting apoptosis and stimulating cell proliferation. Epidemiological studies have reported a positive association between circulating IGF‐1 levels and various primary cancers, such as breast, colorectal, and prostate cancer. The role of IGF‐1 in increasing SPC risk has been explored less. Nonetheless, several experimental studies have observed a deregulation of the IGF‐1 pathway, which may explain the association between IGF‐1 and SPCs. Thus, measuring serum IGF‐1 may serve as a useful marker in assessing the risk of SPCs, and therefore, more translational experimental and epidemiological studies are needed to further disentangle the role of IGF‐1 in the development of specific SPCs.
Clinical significance of granule‐containing myeloma cells in patients with newly diagnosed multiple myeloma
Authors: Suzuki Kazuhito , Yano Shingo , Nishiwaki Kaichi , Sano Koji , Shimada Takaki , Yahagi Yuichi , Ogasawara Yoji , Sugiyama Katsuki , Takahara Shinobu , Saito Takeshi , Kasama Kinuyo , Minami Jiro , Yokoyama Hiroki , Kamiyama Yutaro , Katsube Atsushi , Masuoka Hidekazu , Katori Mitsuji , Machishima Tomohito , Ouchi Aya , Dobashi Nobuaki , Kaito Ken , Usui Noriko , Aiba Keisuke 
Published: October 2016

AbstractThe clinical features and prognostic significance of myeloma cells containing granules remain unclear. The purpose of this retrospective study was to investigate the clinical significance of granule‐containing myeloma cells in patients with newly diagnosed multiple myeloma (NDMM). We retrospectively analyzed the records of 122 patients diagnosed with NDMM between January 2007 and December 2013. Granule‐containing myeloma cells were defined as myeloma cells that exhibited three or more granules in their cytoplasm by May‐Giemsa staining. The patients were classified into two groups, the granule‐containing myeloma (GM) and nongranule‐containing myeloma (non‐GM) groups, depending on the proportion of myeloma cells that contained granules (cut‐off value: 10%). There were 25 (20.5%) patients in the GM group. Patients in the GM group displayed significantly higher CD56 and CD49e expression than those in the non‐GM group (t‐test, P = 0.027 and 0.042). None of the patient characteristics differed significantly between the two groups. There was no significant difference in the chemotherapy profiles of the two groups, and the overall response rates of the two groups were similar. During the median follow‐up period of 33.9 months, the overall survival (OS) in the GM group was similar to that in the non‐GM group; 4‐year OS of the GM and non‐GM groups were 78.5% and 51.9%, respectively (P = 0.126). We concluded that cases of NDMM involving granule‐containing myeloma cells are not infrequent. Moreover, CD56 and CD49e expression was significantly higher in the presence of myeloma cell populations, and the presence of granules did not affect survival.
Al‐doped SBA‐15 Catalysts for Low‐temperature Dehydration of 1,3‐Butanediol into Butadiene
Authors: Jing Fangli , Katryniok Benjamin , Paul Sébastien , Fang Lin , Liebens Armin , Shen Ming , Hu Bingwen , Dumeignil Franck , Pera‐Titus Marc 
Published: October 2016

AbstractSBA‐15 catalysts doped with variable aluminum amounts were prepared through a facile evaporation‐induced self‐assembly process. The textural properties and acidity of the catalysts could be tuned simply by varying the aluminum content. The genesis of acid sites with weak and medium strength during reaction was directly correlated to the catalytic activity for the dehydration of 1,3‐butanediol into butadiene (BD). The best performance was achieved over an Al‐SBA‐15 sample with a silica/alumina ratio of 76, exhibiting a stable BD yield of 59 % at temperatures as low as 200 °C.
Synthesis of Hierarchically Porous Sandwich‐Like Carbon Materials for High‐Performance Supercapacitors
Authors: Li Yiju , Chen Chaoji , Gao Tingting , Zhang Dongming , Huang Xiaomei , Pan Yue , Ye Ke , Cheng Kui , Cao Dianxue , Wang Guiling 
Published: October 2016

AbstractFor the first time, hierarchically porous carbon materials with a sandwich‐like structure are synthesized through a facile and efficient tri‐template approach. The hierarchically porous microstructures consist of abundant macropores and numerous micropores embedded into the crosslinked mesoporous walls. As a result, the obtained carbon material with a unique sandwich‐like structure has a relatively high specific surface (1235 m2 g−1), large pore volume (1.30 cm3 g−1), and appropriate pore size distribution. These merits lead to a comparably high specific capacitance of 274.8 F g−1 at 0.2 A g−1 and satisfying rate performance (87.7 % retention from 1 to 20 A g−1). More importantly, the symmetric supercapacitor with two identical as‐prepared carbon samples shows a superior energy density of 18.47 Wh kg−1 at a power density of 179.9 W kg−1. The asymmetric supercapacitor based on as‐obtained carbon sample and its composite with manganese dioxide (MnO2) can reach up to an energy density of 25.93 Wh kg−1 at a power density of 199.9 W kg−1. Therefore, these unique carbon material open a promising prospect for future development and utilization in the field of energy storage.