bluuebunny/crossref_metadata_2025_split huggingface dataset:
Luminescent (N^C^C) Gold(III) Complexes: Stabilized Gold(III) Fluorides
Authors: Kumar Roopender , Linden Anthony , Nevado Cristina 
Published: October 2015

AbstractWe report the design, synthesis, and application of a (N^C^C)‐ligand framework able to stabilize highly electron‐deprived gold(III) species. This novel platform enabled the preparation of C(sp2)‐gold(III) fluorides for the first time in monomeric, easy‐to‐handle, bench‐stable form by a Cl/F ligand‐exchange reaction. Devoid of oxidative conditions or stoichiometric use of toxic Hg salts, this method was applied to the preparation of multiple [C(sp2)‐AuIII‐F] complexes, which were used as mechanistic probes for the study of the unique properties and intrinsic reactivity of AuF bonds. The improved photophysical properties of [(N^C^C)AuIII] complexes compared to classical pincer (C^N^C)‐Au systems paves the way for the design of new late‐transition‐metal‐based OLEDs.
Polymerkäfige als universelles Hilfsmittel für die präzise Bottom‐up‐Synthese metallischer Nanopartikel
Authors: Fan Ziyin , Chen Xuelian , Köhn Serrano Melissa , Schmalz Holger , Rosenfeldt Sabine , Förster Stephan , Agarwal Seema , Greiner Andreas 
Published: October 2015

AbstractEine neue, Templat‐gestützte Synthese monodisperser Nanopartikel stellt keine Anforderungen an die Selbstorganisation und ist hoch reproduzierbar. Hierzu werden maßgeschneiderte Polymerkäfige für die Synthese von Nanopartikeln verwendet, die aus vernetzten Makromolekülen mit Thiolendgruppen bestehen. Goldnanopartikel (AuNPs) wurden in verschiedenen Verhältnissen von Polymerkäfig zu Gold in situ in den Polymerkäfigen synthetisiert. Die Polymerkäfige zeichneten sich dabei durch eine definierte Beladungskapazität aus, mit exzellenter Kontrolle über Form und Größe. Dagegen zeigten Kontrollversuche mit linearen Diblockcopolymeren einen linearen Anstieg der Partikelgrößen mit steigendem Goldanteil. Das unterschiedliche Wachstumsverhalten der AuNPs wird durch die Vernetzungsgrad‐abhängige Flexibilität der Polymerketten erklärt. Des Weiteren wird die Polymerkäfig‐gesteuerte In‐situ‐Synthese auf Silber‐ (AgNPs), Palladium‐ (PdNPs) und Platinnanopartikel (PtNPs) übertragen.
Unusual Aggregation‐Induced Emission of a Coumarin Derivative as a Result of the Restriction of an Intramolecular Twisting Motion
Authors: Bu Fan , Duan Ruihong , Xie Yujun , Yi Yuanping , Peng Qian , Hu Rongrong , Qin Anjun , Zhao Zujin , Tang Ben Zhong 
Published: October 2015

AbstractAggregation‐induced emission (AIE) is commonly observed for propeller‐like luminogens with aromatic rotors and stators. Herein, we report that a coumarin derivative containing a seven‐membered aliphatic ring (CD‐7) but no rotors showed typical AIE characteristics, whereas its analogue with a five‐membered aliphatic ring (CD‐5) exhibited an opposite aggregation‐caused quenching (ACQ) effect. Experimental and theoretical results revealed that a large aliphatic ring in CD‐7 weakens structural rigidity and promotes out‐of‐plane twisting of the molecular backbone to drastically accelerate nonradiative excited‐state decay, thus resulting in poor emission in solution. The restriction of twisting motion in aggregates blocks the nonradiative decay channels and enables CD‐7 to fluoresce strongly. The results also show that AIE is a general phenomenon and not peculiar to propeller‐like molecules. The AIE and ACQ effects can be switched readily by the modulation of molecular rigidity.
The Unexpected Influence of Precursor Conversion Rate in the Synthesis of III–V Quantum Dots
Authors: Franke Daniel , Harris Daniel K. , Xie Lisi , Jensen Klavs F. , Bawendi Moungi G. 
Published: October 2015

AbstractControl of quantum dot (QD) precursor chemistry has been expected to help improve the size control and uniformity of III–V QDs such as indium phosphide and indium arsenide. Indeed, experimental results for other QD systems are consistent with the theoretical prediction that the rate of precursor conversion is an important factor controlling QD size and size distribution. We synthesized and characterized the reactivity of a variety of group‐V precursors in order to determine if precursor chemistry could be used to improve the quality of III–V QDs. Despite slowing down precursor conversion rate by multiple orders of magnitude, the less reactive precursors do not yield the expected increase in size and improvement in size distribution. This result disproves the widely accepted explanation for the shortcoming of current III–V QD syntheses and points to the need for a new generalizable theoretical picture for the mechanism of QD formation and growth.
Streptocollin, a Type IV Lanthipeptide Produced by Streptomyces collinus Tü 365
Authors: Iftime Dumitrita , Jasyk Martin , Kulik Andreas , Imhoff Johannes F. , Stegmann Evi , Wohlleben Wolfgang , Süssmuth Roderich D. , Weber Tilmann 
Published: October 2015

AbstractLanthipeptides are ribosomally synthesized and post‐translationally modified microbial secondary metabolites. Here, we report the identification and isolation of streptocollin from Streptomyces collinus Tü 365, a new member of class IV lanthipeptides. Insertion of the constitutive ermE* promoter upstream of the lanthipeptide synthetase gene stcL resulted in peptide production. The streptocollin gene cluster was heterologously expressed in S. coelicolor M1146 and M1152 with 3.5‐ and 5.5‐fold increased yields, respectively. The structure and ring topology of streptocollin were determined by high resolution MS/MS analysis. Streptocollin contains four macrocyclic rings, with one lanthionine and three methyllanthionine residues. To the best of our knowledge, this is the first report on the isolation of a class IV lanthipeptide in preparative amounts, and on the successful heterologous expression of a class IV lanthipeptide gene cluster.
Regiocomplementary O‐Methylation of Catechols by Using Three‐Enzyme Cascades
Authors: Siegrist Jutta , Aschwanden Simon , Mordhorst Silja , Thöny‐Meyer Linda , Richter Michael , Andexer Jennifer N. 
Published: October 2015

AbstractS‐Adenosylmethionine (SAM)‐dependent enzymes have great potential for selective alkylation processes. In this study we investigated the regiocomplementary O‐methylation of catechols. Enzymatic methylation is often hampered by the need for a stoichiometric supply of SAM and the inhibitory effect of the SAM‐derived byproduct on most methyltransferases. To counteract these issues we set up an enzyme cascade. Firstly, SAM was generated from l‐methionine and ATP by use of an archaeal methionine adenosyltransferase. Secondly, 4‐O‐methylation of the substrates dopamine and dihydrocaffeic acid was achieved by use of SafC from the saframycin biosynthesis pathway in 40–70 % yield and high selectivity. The regiocomplementary 3‐O‐methylation was catalysed by catechol O‐methyltransferase from rat. Thirdly, the beneficial influence of a nucleosidase on the overall conversion was demonstrated. The results of this study are important milestones on the pathway to catalytic SAM‐dependent alkylation processes.
Mathematical Modeling of Coke Formation and Deposition due to Thermal Cracking of Petroleum Fluids
Authors: Solaimany Nazar Ali R. , Banisharifdehkordi Farhad , Ahmadzadeh Sareh 
Published: October 2015

AbstractA two‐dimensional mathematical dynamics model is presented to predict coke formation due to thermal cracking inside the tubes of fired heaters on two types of petroleum fluid. The laminar and turbulent flows are analyzed for both petroleum fluids. The second‐order k‐ϵ standard model is adopted to make this mathematical model more accurate than previous models of coke formation. The radial and axial variations for temperature, velocity, and concentration due to the high temperature gradients inside the tubes are considered in the model equations. The finite volume method is the numerical model used to discretize the conservation equations. The proposed model is suitable to predict coke formation inside heater tubes since it indicates operational conditions where coke formation is minimized.
Process Design in World 3.0 – Challenges and Strategies to Master the Raw Material Change
Authors: Burger Jakob , Ströfer Eckhard , Hasse Hans 
Published: October 2015

AbstractThe evolution of global energy supply chains leads to a raw material change in the chemical industry. Despite this change, the value‐added chains of the chemical industry have to keep up their output of diverse high‐quality products desired by the customers. C1 chemistry in combination with suitable conversion technologies yielding olefins and aromatics will play a key role in mastering this challenge. New chemical value‐added chains have to be developed and assessed, resulting in an increasing importance of conceptual process design. All this will take place in what Ghemawat has called the World 3.0, a globally linked but regionally diverse world. This diversity creates further challenges for process design in the chemical industries. A systematic concept to address these challenges is given here, including strategies for optimization and decision support.
Polyaniline‐Induced CH Arylation of Arenes with Arenediazonium Salts
Authors: Amaya Toru , Hata Dai , Moriuchi Toshiyuki , Hirao Toshikazu 
Published: October 2015

AbstractA reduced form of polyaniline has been shown to induce direct arylation of an arenediazonium salt with an arene (Gomberg–Bachmann reaction) to give the cross‐coupling product in moderate to good yields under mild conditions. Various arenediazonium salts and arenes, including heteroarenes such as furans, thiophenes, and pyrroles, are employed for the reaction. The most favorable combination of substrates is an electron‐poor arenediazonium salt with an electron‐rich heteroarene. Investigation of the mechanism by reactions with radical scavengers and experiments on kinetic isotope effects indicated the occurrence of a radical chain reaction initiated by one‐electron reduction of an arenediazonium salt by the polyaniline. Only 1 mol % (based on aniline tetramer) of the polyaniline is required for the cross‐coupling reaction to occur. This reaction proceeds under metal‐free conditions and with no need for photonic activation.
Synthesis and Analysis of the Structure, Diffusion and Cytotoxicity of Heterocyclic Platinum(IV) Complexes
Authors: Macias Freddy J. , Deo Krishant M. , Pages Benjamin J. , Wormell Paul , Clegg Jack K. , Zhang Yingjie , Li Feng , Zheng Gang , Sakoff Jennette , Gilbert Jayne , Aldrich‐Wright Janice R. 
Published: October 2015

AbstractWe have developed six dihydroxidoplatinum(IV) compounds with cytotoxic potential. Each derived from active platinum(II) species, these complexes consist of a heterocyclic ligand (HL) and ancillary ligand (AL) in the form [Pt(HL)(AL)(OH)2]2+, where HL is a methyl‐functionalised variant of 1,10‐phenanthroline and AL is the S,S or R,R isomer of 1,2‐diaminocyclohexane. NMR characterisation and X‐ray diffraction studies clearly confirmed the coordination geometry of the octahedral platinum(IV) complexes. The self‐stacking of these complexes was determined using pulsed gradient stimulated echo nuclear magnetic resonance. The self‐association behaviour of square planar platinum(II) complexes is largely dependent on concentration, whereas platinum(IV) complexes do not aggregate under the same conditions, possibly due to the presence of axial ligands. The cytotoxicity of the most active complex, exhibited in several cell lines, has been retained in the platinum(IV) form.
Stereoselective [3+2] Carbocyclization of Indole‐Derived Imines and Electron‐Rich Alkenes: A Divergent Synthesis of Cyclopenta[b]indole or Tetrahydroquinoline Derivatives
Authors: Galván Alicia , Calleja Jonás , González‐Pérez Adán B. , Álvarez Rosana , de Lera Angel R. , Fañanás Francisco J. , Rodríguez Félix 
Published: October 2015

AbstractAn unprecedented stereoselective [3+2] carbocyclization reaction of indole‐2‐carboxaldehydes, anilines, and electron‐rich alkenes to obtain cyclopenta[b]indoles is disclosed. This pathway is different from the well‐established Povarov reaction: the formal [4+2] cycloaddition involving the same components, which affords tetrahydroquinolines. Moreover, by simply changing the Brønsted acid catalyst, this multicomponent coupling process could be divergently directed towards the conventional Povarov pathway to produce tetrahydroquinolines or to the new pathway (anti‐Povarov) to generate cyclopenta[b]indoles. Supported by computational studies, a stepwise Mannich/Friedel–Crafts cascade is proposed for the new anti‐Povarov reaction, whereas a concerted [4+2] cycloaddition mechanism is proposed for the Povarov reaction.
Synthesis of Well‐Defined Oligo(2,5‐dialkoxy‐1,4‐phenylene vinylene)s with Chiral End Groups: Unique Helical Aggregations Induced by the Chiral Chain Ends
Authors: Yorsaeng Sakkawet , Kato Yuka , Tsutsumi Ken , Inagaki Akiko , Kitiyanan Boonyarach , Fujiki Michiya , Nomura Kotohiro 
Published: October 2015

AbstractOligo(2,5‐dialkoxy‐1,4‐phenylenevinylene)s containing three different chiral alkoxy substituents on the phenyl end groups with structurally regular (all trans) controlled repeat units have been prepared; these compounds showed highly enhanced aggregation‐induced circular dichroism (AICD; formation of supramolecular polymers), and an inversion of the CD signal was observed even with the same end groups under certain conditions.
The Effect of Temperature on the Overpressure Distribution and Formation in the Central Paleo‐Uplift of the Sichuan Basin
Authors: Yi‐Feng LIU , Lun‐Ju ZHENG , Nan‐Sheng QIU , Jing‐Kun JIA , Qing CHANG 
Published: October 2015

AbstractTemperature and pore pressure are two important physical fields in sedimentary basins. Temperature controls the distribution characteristics and formation of overpressures. Firstly, the relationship between the measured temperature and pore pressure was analyzed. Secondly, temperature‐pressure relationship for sealed formation water was modeled in laboratory. The maximum paleo‐temperatures for different regions in the Paleo‐Uplift were reconstructed by using vitrinite reflectance, and then the effect of temperature on the overpressure distribution characteristics was analyzed. Finally, the impacts of temperature on the overpressure generation through oil cracking and disequilibrium compaction were discussed. Based on the study results, a positive correlation between the temperature and pressure in the Central Paleo‐Uplift was discovered. When the pressure is greater than 15 MPa, it would change 1.076 MPa as temperature change 1 °C in an absolutely sealed condition. The difference in temperature reduction is the primary cause for various intensity of pressure within the Central Paleo‐Uplift. Besides that, lateral transfer and leakage of pressure must occur. Overpressure in the Lower Paleozoic, generated by oil cracking, formed during from 180 to 110 Ma and redistributed in 90 Ma. Temperature effect on disequilibrium compaction overpressure is negligible.
Differences of Structure in Mid‐Lower Crust between the Eastern and Western Blocks of the Sichuan basin
Authors: Xiao‐Song XIONG , Rui GAO , Ji‐Sheng ZHANG , Hai‐Yang WANG , Liang‐Hui GUO 
Published: October 2015

AbstractThe Sichuan basin is the main part of the Middle‐upper Yangtze craton, which has experienced a long tectonic evolution since Archean. It was regarded as a stable block until the collision with the Cathaysia block in late Neoproterozoic. As one of the largest and most complex Archean cratons in China, the Yangtze craton consists of Archean‐Paleoproterozoic crystalline basement (mostly covered) outcropped in the western and southwestern margins and the Three Gorge area surrounded by late Mesoproterozoic to early Neoproterozoic fold belts, which are locally unconformably overlain by middle Neoproterozoic weakly metamorphosed strata and late Neoproterozoic unmetamorphosed Sinian and Phanerozoic cover. These strata limit the understanding of the nature and distribution characteristics of the middle‐lower crust beneath the sedimentary rocks. Gravity anomalies can reveal the overall regional structure. In this paper we obtain the middle‐lower crustal gravity anomalies by removing the gravity anomalies induced by the sedimentary rocks and the mantle beneath the Moho, which shows that the mid‐lower crustal structure of the Sichuan Basin can be divided into eastern and western parts. Combined with the deep seismic reflection data and other geochemical and geophysical data, we propose that the boundary of mid‐lower crust between the eastern and western parts is along the Chongqing‐Huaying line, which may indicate that there are two continental nucleuses beneath the Yangtze block.
The joy of proofs in statistical research
Authors: Chen Jiahua 
Published: October 2015

AbstractWithout exception, great statisticians have penetrating statistical insight. Technical strength is likely secondary in their research, although it never hurts. In contrast, mathematical skill has been pivotal in my work, particularly in combination with my proximity to many great statistical minds. In the occasion of receiving the Gold Medal of the Statistical Society of Canada, I wish to attribute part of my success to the joy of proofs. Proofs are an indispensable ingredient in my research achievements. I hasten to add that proofs are delightful only if they help to develop innovative statistical methods: proving theorems solely for the sake of publication can be boring and a waste of time. With this preamble, I selectively present some research achievements and encourage other researchers to proudly maximize the benefits of their technical strength. The Canadian Journal of Statistics 43: 481–497; 2015 © 2015 Statistical Society of Canada
Trends, predictors, and impact of systemic chemotherapy in small cell lung cancer patients between 1985 and 2005
Authors: Behera Madhusmita , Ragin Camille , Kim Sungjin , Pillai Rathi N. , Chen Zhengjia , Steuer Conor E. , Saba Nabil F. , Belani Chandra P. , Khuri Fadlo R. , Ramalingam Suresh S. , Owonikoko Taofeek K. 
Published: October 2015

BACKGROUNDThe last 3 decades have witnessed limited therapeutic advances in small cell lung cancer (SCLC) management. This study evaluated real‐world trends in the use of systemic therapies and the impact on patient outcomes in the United States.METHODSThe Surveillance, Epidemiology, and End Results–Medicare database was used to find patients diagnosed with SCLC between 1985 and 2005. The 1985‐1990 period served as the baseline for a temporal analysis conducted at 5‐year intervals (1985‐1990, 1991‐1995, 1996‐2000, and 2001‐2005). Cox proportional models were used to estimate the effect of chemotherapy on survival. Results were validated with a propensity‐matched analysis.RESULTSThere were 47,351 eligible patients: 52% were male; the median age was 71 years; and 87% were white, 7% were black, and 1.4% were Asian. The proportion of patients treated with chemotherapy was low but increased over time (38%, 55%, 50%, and 53%;P< .001). Race, diagnosis period, age, stage, and location of residence significantly predicted chemotherapy use. Females (51%), Asians (53%), and rural residents (60%) were more likely to receive chemotherapy. The median overall survival with and without chemotherapy was 9.6 and 3.6 months, respectively. Linear trend analyses showed a modest reduction in the impact of chemotherapy on survival for patients treated with chemotherapy versus untreated patients (hazard ratios [HRs], 0.59, 0.61, 0.64, and 0.62;P< .001) but an overall trend of improved survival for treated (HRs, 1.0, 1.03, 1.00, and 0.96;P= .005) and untreated patients (HRs, 1.0, 0.99, 0.94, and 0.92;P< .001). There was no survival difference between patients treated with carboplatin and patients treated with cisplatin (HR, 0.99; confidence interval [CI], 0.81‐1.19;P= .875). Additional therapy beyond platinum‐based chemotherapy was associated with a survival benefit (HR, 0.78; CI, 0.75‐0.81;P< .001).CONCLUSIONSChemotherapy use was associated with a survival benefit in Medicare patients with SCLC treated in a real‐world setting.Cancer2016;122:50–60.©2015 American Cancer Society.
Photopolymer Electrolytes for Sustainable, Upscalable, Safe, and Ambient‐Temperature Sodium‐Ion Secondary Batteries
Authors: Bella Federico , Colò Francesca , Nair Jijeesh R. , Gerbaldi Claudio 
Published: October 2015

AbstractThe first example of a photopolymerized electrolyte for a sodium‐ion battery is proposed herein. By means of a preparation process free of solvents, catalysts, purification steps, and separation steps, it is possible to obtain a three‐dimensional polymeric network capable of efficient sodium‐ion transport. The thermal properties of the resulting solid electrolyte separator, characterized by means of thermogravimetric and calorimetric techniques, are excellent for use in sustainable energy systems conceived for safe large‐scale grid storage. The photopolymerized electrolyte shows a wide electrochemical stability window up to 4.8 V versus Na/Na+ along with the highest ionic conductivity (5.1 mS cm−1 at 20 °C) obtained in the field of Na‐ion polymer batteries so far and stable long‐term constant‐current charge/discharge cycling. Moreover, the polymeric networks are also demonstrated for the in situ fabrication of electrode/electrolyte composites with excellent interfacial properties, which are ideal for all‐solid‐state, safe, and easily upscalable device assembly.
Mechanistic Insight into a Sugar‐Accelerated Tin‐Catalyzed Cascade Synthesis of α‐Hydroxy‐γ‐butyrolactone from Formaldehyde
Authors: Yamaguchi Sho , Matsuo Takeaki , Motokura Ken , Sakamoto Yasuharu , Miyaji Akimitsu , Baba Toshihide 
Published: October 2015

AbstractApplications of the formose reaction, which involves the formation of sugars from formaldehyde, have previously been confined to the selective synthesis of unprotected sugars. Herein, it is demonstrated that α‐hydroxy‐γ‐butyrolactone (HBL), which is one of the most important intermediates in pharmaceutical syntheses, can be produced from paraformaldehyde. In the developed reaction system, homogeneous tin chloride exhibits high catalytic activity and the addition of mono‐ and disaccharides accelerates the formation of HBL. These observations suggest that the formose reaction may serve as a feasible pathway for the synthesis of important chemicals.
Computational Investigation of the 1,4‐Rh Shift in the [(Ph2PCH2CH2PPh2)Rh]‐Catalyzed Alkyne Arylation Reaction
Authors: Kantchev Eric Assen B. , Zhou Feng , Pangestu Surya R. , Sullivan Michael B. , Su Haibin 
Published: October 2015

AbstractComputations (density functional theory) of the post‐transmetallation stages (carborhodation, 1,4‐shift consisting of C–H oxidative addition/C–H reductive elimination, and hydrolysis) in the catalytic cycle for the arylation of 2‐butyne with phenylboronic acid mediated by [(dppe)RhI] catalyst [dppe = 1,2‐bis(diphenylphosphanyl)ethane] shows that (1) carborhodation is facile (ΔG‡ ≈ 10 kcal mol–1); (2) the barriers of the 1,4‐shift and hydrolysis are approximately equal (ΔG‡ ≈ 19–24 kcal mol–1); (3) the 1,4‐Rh shift product is ca. 5 kcal mol–1 more stable than the non‐rearranged product, in good agreement with the experimental results. Analogous computations for (Z)‐2‐butene as a model substrate show that (1) carborhodation is much slower (ΔG‡ ≈ 19 kcal mol–1); (2) the sp3 → sp2 1,4‐shift is faster than the sp2 → sp2 1,4‐shift; (3) the hydrolysis of Rh–C σ bonds depends more on the steric environment than the hybridization of the C atom; and (4) β‐hydride elimination is the most likely reaction after carborhodation.