bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymatic Synthesis of Optically Active Lactones via Asymmetric Bioreduction using Ene‐Reductases from the Old Yellow Enzyme Family
Authors: Turrini Nikolaus G. , Hall Mélanie , Faber Kurt 
Published: May 2015

AbstractIn contrast to the widely studied asymmetric bioreduction of α,β‐unsaturated carboxylic acid esters catalyzed by ene‐reductases, the reaction applied to lactones remains unexplored. A broad set of ene‐reductases was found to reduce various α‐, β‐ and γ‐substituted α,β‐unsaturated butyrolactones to yield the corresponding saturated non‐racemic lactones. Substitution patterns greatly influenced activities and stereoselectivities and lactone products were obtained in moderate to excellent yields; importantly, enzyme‐based stereocontrol allowed access to both enantiomers in up to >99% ee. Chiral recognition of a distant γ‐center led to kinetic resolution with remarkable enantioselectivities (E values up to 49). An unprecedented case of dynamic kinetic resolution was observed with 3‐methyl‐5‐phenylfuran‐2(5H)‐one, whereby spontaneous racemization of the substrate furnished the product in up to 73% conversion and >99% ee and 96% de.magnified image
Is the area of the orbital opening in humans related to climate?
Authors: Tomaszewska Agnieszka , Kwiatkowska Barbara , Jankauskas Rimantas 
Published: May 2015

ObjectivesThe aim of this study was to evaluate whether climatic conditions impact the size of the anterior orbital opening in humans. The previous research has shown that morphology of the human orbit, a trait strongly related to the shape of the cranium, varies significantly among populations. However, the mechanisms of this variation are still debatable. Besides such evolutionary forces as genetic drift, climatic conditions may be involved. Thermoregulatory processes affect skull shape, and thus may also influence orbital morphology.MethodsA total of 846 dry skulls of male and female adults from three climatic areas (i.e., warm, temperate, and cold) of Europe were evaluated. The areas of the left and right orbital openings were measured using the three‐dimensional contact scanner MicroScribe G2L, and analyzed with regard to climate.ResultsThe results reveal a statistically significant association with climatic conditions on the area of orbital opening in accordance with Bergmann's rule. The anterior orbital opening area was smaller in male individuals from the cold climate, and larger in individuals from the warm climate areas.ConclusionsThese data may support the hypothesized association between size of the orbital opening and adaptation to different climatic conditions, but only in males. Am. J. Hum. Biol. 27:845–850, 2015. © 2015 Wiley Periodicals, Inc.
Water Structure Recovery in Chaotropic Anion Recognition: High‐Affinity Binding of Dodecaborate Clusters to γ‐Cyclodextrin
Authors: Assaf Khaleel I. , Ural Merve S. , Pan Fangfang , Georgiev Tony , Simova Svetlana , Rissanen Kari , Gabel Detlef , Nau Werner M. 
Published: May 2015

AbstractDodecaborate anions of the type B12X122− and B12X11Y2− (X=H, Cl, Br, I and Y=OH, SH, NH3+, NR3+) form strong (Ka up to 106 L mol−1, for B12Br122−) inclusion complexes with γ‐cyclodextrin (γ‐CD). The micromolar affinities reached are the highest known for this native CD. The complexation exhibits highly negative enthalpies (up to −25 kcal mol−1) and entropies (TΔS up to −18.4 kcal mol−1, both for B12I122−), which position these guests at the bottom end of the well‐known enthalpy‐entropy correlation for CDs. The high driving force can be traced back to a chaotropic effect, according to which chaotropic anions have an intrinsic affinity to hydrophobic cavities in aqueous solution. In line with this argument, salting‐in effects revealed dodecaborates as superchaotropic dianions.
Thermally Responsive Hydrogel Blends: A General Drug Carrier Model for Controlled Drug Release
Authors: Ma Chongbo , Shi Ye , Pena Danilo A. , Peng Lele , Yu Guihua 
Published: May 2015

AbstractThermally responsive hydrogels have drawn significant research attention recently because of their simple use as drug carrier at human body temperature. Here we design a hybrid hydrogel that incorporates a hydrophilic polymer, polyethyleneimine (PEI), into the thermally responsive hydrogel poly(N‐isopropylacrylamide) (PNIPAm), as a general drug carrier model for controlled drug release. In this work, on one hand, PEI modifies the structure and the size of the pores in the PNIPAm hydrogel. On the other hand, PEI plays an important role in tuning the water content in the hydrogel and controls the water release rate of the hydrogel below the lower critical solution temperature (LCST), resulting in a tunable release rate of the drugs at human body temperature (37 °C). Different release rates are shown as different amounts of PEI are incorporated. PEI controls the release rate, dependent on the charge characteristics of the drugs. The hydrogel blends described in this work extend the concept of a general drug carrier for loading both positively and negatively charged drugs, as well as the controlled release effect.
A Halogen‐Bonded Dimeric Resorcinarene Capsule
Authors: Beyeh Ngong Kodiah , Pan Fangfang , Rissanen Kari 
Published: May 2015

AbstractIodine (I2) acts as a bifunctional halogen‐bond donor connecting two macrocyclic molecules of the bowl‐shaped halogen‐bond acceptor, N‐cyclohexyl ammonium resorcinarene chloride 1, to form the dimeric capsule [(1,4‐dioxane)3@12(I2)2]. The dimeric capsule is constructed solely through halogen bonds and has a single cavity (V=511 Å3) large enough to encapsulate three 1,4‐dioxane guest molecules.
Organocatalytic, Asymmetric Eliminative [4+2] Cycloaddition of Allylidene Malononitriles with Enals: Rapid Entry to Cyclohexadiene‐Embedding Linear and Angular Polycycles
Authors: Brindani Nicoletta , Rassu Gloria , Dell'Amico Luca , Zambrano Vincenzo , Pinna Luigi , Curti Claudio , Sartori Andrea , Battistini Lucia , Casiraghi Giovanni , Pelosi Giorgio , Greco Daniela , Zanardi Franca 
Published: May 2015

AbstractA direct aminocatalytic synthesis has been developed for the chemo‐, regio‐, diastereo‐, and enantioselective construction of densely substituted polycyclic carbaldehydes containing fused cyclohexadiene rings. The chemistry utilizes, for the first time, remotely enolizable π‐extended allylidenemalononitriles as electron‐rich 1,3‐diene precursors in a direct eliminative [4+2] cycloaddition with both aromatic and aliphatic α,β‐unsaturated aldehydes. The generality of the process is demonstrated by approaching 6,6‐, 5,6‐, 7,6‐, 6,6,6‐, and 6,5,6‐fused ring systems, as well as biorelevant steroid‐like 6,6,6,6,5‐ and 6,6,6,5,6‐rings. A stepwise reaction mechanism for the key [4+2] addition is proposed as a domino bis‐vinylogous Michael/Michael/retro‐Michael reaction cascade. The utility of the malononitrile moiety as traceless activating group of the dicyano nucleophilic substrates is demonstrated.
Textile/Metal–Organic‐Framework Composites as Self‐Detoxifying Filters for Chemical‐Warfare Agents
Authors: López‐Maya Elena , Montoro Carmen , Rodríguez‐Albelo L. Marleny , Aznar Cervantes Salvador D. , Lozano‐Pérez A. Abel , Cenís José Luis , Barea Elisa , Navarro Jorge A. R. 
Published: May 2015

AbstractThe current technology of air‐filtration materials for protection against highly toxic chemicals, that is, chemical‐warfare agents, is mainly based on the broad and effective adsorptive properties of hydrophobic activated carbons. However, adsorption does not prevent these materials from behaving as secondary emitters once they are contaminated. Thus, the development of efficient self‐cleaning filters is of high interest. Herein, we report how we can take advantage of the improved phosphotriesterase catalytic activity of lithium alkoxide doped zirconium(IV) metal–organic framework (MOF) materials to develop advanced self‐detoxifying adsorbents of chemical‐warfare agents containing hydrolysable PF, PO, and CCl bonds. Moreover, we also show that it is possible to integrate these materials onto textiles, thereby combining air‐permeation properties of the textiles with the self‐detoxifying properties of the MOF material.
Stable π Radical from a Contracted Doubly N‐Confused Hexaphyrin by Double Palladium Metalation
Authors: Hisamune Yutaka , Nishimura Keiichi , Isakari Koji , Ishida Masatoshi , Mori Shigeki , Karasawa Satoru , Kato Tatsuhisa , Lee Sangsu , Kim Dongho , Furuta Hiroyuki 
Published: May 2015

AbstractA contracted doubly N‐confused dioxohexaphyrin derivative served as a dinucleating metal ligand for unsymmetrical coordination. The complexation of two palladium(II) cations led to the formation of π‐radical species that were persistent in atmospheric air in the presence of moisture. Effective delocalization of an unpaired electron over the hexaphyrin backbone could contribute to the distinct chemical stability.
Mechanochemical Rhodium(III)‐Catalyzed CH Bond Functionalization of Acetanilides under Solventless Conditions in a Ball Mill
Authors: Hermann Gary N. , Becker Peter , Bolm Carsten 
Published: May 2015

AbstractIn a proof‐of‐principle study, a planetary ball mill was applied to rhodium(III)‐catalyzed CH bond functionalization. Under solventless conditions and in the presence of a minute amount of Cu(OAc)2, the mechanochemical activation led to the formation of an active rhodium species, thus enabling an oxidative Heck‐type cross‐coupling reaction with dioxygen as the terminal oxidant. The absence of an organic solvent, the avoidance of a high reaction temperature, the possibility of minimizing the amount of the metallic mediator, and the simplicity of the protocol result in a powerful and environmentally benign alternative to the common solution‐based standard protocol.
Aerogen Bonding Interaction: A New Supramolecular Force?
Authors: Bauzá Antonio , Frontera Antonio 
Published: May 2015

AbstractWe report evidence of the favorable noncovalent interaction between a covalently bonded atom of Group 18 (known as noble gases or aerogens) and a negative site, for example, a lone pair of a Lewis base or an anion. It involves a region of positive electrostatic potential (σ‐hole), therefore it is a totally new and unexplored σ‐hole‐based interaction, namely aerogen bonding. We demonstrate for the first time the existence of σ‐hole regions in aerogen derivatives by means of high‐level ab initio calculations. In addition, several crystal structures retrieved from the Cambridge Structural Database (CSD) give reliability to the calculations. Energetically, aerogen bonds are comparable to hydrogen bonds and other σ‐hole‐based interactions but less directional. They are expected to be important in xenon chemistry.
Enantioselective Construction of 3‐Hydroxypiperidine Scaffolds by Sequential Action of Light and Rhodium upon N‐Allylglyoxylamides
Authors: Ishida Naoki , Nečas David , Masuda Yusuke , Murakami Masahiro 
Published: May 2015

Abstract3‐Hydroxypiperidine scaffolds were enantioselectively constructed in an atom‐economical way by sequential action of light and rhodium upon N‐allylglyoxylamides. In a formal sense, the allylic CH bond was selectively cleaved and enantioselectively added across the ketonic carbonyl group with migration of the double bond (carbonyl‐ene‐type reaction).
Chiral Selective Chemistry Induced by Natural Selection of Spin‐Polarized Electrons
Authors: Rosenberg Richard A. , Mishra Debabrata , Naaman Ron 
Published: May 2015

AbstractThe search to understand the origin of homochirality in nature has been ongoing since the time of Pasteur. Previous work has shown that DNA can act as a spin filter for low‐energy electrons and that spin‐polarized secondary electrons produced by X‐ray irradiation of a magnetic substrate can induce chiral selective chemistry. In the present work it is demonstrated that secondary electrons from a substrate that are transmitted through a chiral overlayer cause enantiomeric selective chemistry in an adsorbed adlayer. We determine the quantum yields (QYs) for dissociation of (R)‐ or (S)‐epichlorohydrin adsorbed on a chiral self‐assembled layer of DNA on gold and on bare gold (for control). The results show that there is a significant difference in the QYs between the two enantiomers when adsorbed on DNA, but none when they are adsorbed on bare Au. We propose that the effect results from natural spin filtering effects cause by the chiral monolayer.
Michael Addition Catalyzed by Chiral Secondary Amine Phosphoramide Using Fluorinated Silyl Enol Ethers: Formation of Quaternary Carbon Stereocenters
Authors: Yu Jin‐Sheng , Liao Fu‐Min , Gao Wei‐Ming , Liao Kui , Zuo Run‐Lin , Zhou Jian 
Published: May 2015

AbstractA chiral secondary amine phosphoramide was developed and identified as a powerful catalyst for the Mukaiyama–Michael addition of fluorinated enol silyl ethers to tetrasubstituted olefins. The resulting products are obtained with high enantioselectivities and contain a quaternary carbon stereocenter bearing either a difluoroalkyl or monofluoroalkyl group.
Highly Amino Acid Selective Hydrolysis of Myoglobin at Aspartate Residues as Promoted by Zirconium(IV)‐Substituted Polyoxometalates
Authors: Ly Hong Giang T. , Absillis Gregory , Janssens Rik , Proost Paul , Parac‐Vogt Tatjana N. 
Published: May 2015

AbstractSDS‐PAGE/Edman degradation and HPLC MS/MS showed that zirconium(IV)‐substituted Lindqvist‐, Keggin‐, and Wells–Dawson‐type polyoxometalates (POMs) selectively hydrolyze the protein myoglobin at AspX peptide bonds under mildly acidic and neutral conditions. This transformation is the first example of highly sequence selective protein hydrolysis by POMs, a novel class of protein‐hydrolyzing agents. The selectivity is directed by Asp residues located on the surface of the protein and is further assisted by electrostatic interactions between the negatively charged POMs and positively charged surface patches in the vicinity of the cleavage site.
Preparation and characterization of poly(o‐anisidine) with the influence of surfactants on stainless steel by electrochemical polymerization as a counter electrode for dye‐sensitized solar cells
Authors: Menaka Chandrasekaran , Manisankar Paramasivam , Stalin Thambusamy 
Published: May 2015

ABSTRACTEfficient fast electron transfer from counter electrode to an electrolyte is a key process during the operation of dye‐sensitized solar cells (DSSCs). We introduce a surfactants assisted electro‐polymerized poly(o‐anisidine) (POA) counter electrodes (CE) for DSSCs. Commencing the electrochemical impedance spectroscopy, the POA/sodium dodecyl sulphate (SDS) CE exhibited very low series and charge‐transfer resistance. This is due to high electrocatalytic activity confirmed by cyclic voltammetry, surface area and the conductivity of the stainless steel film. The photovoltaic performance of POA/SDS counter electrode shows an energy conversion efficiency of 2.5% under 1 sun illumination. Short‐term stability test for POA/SDS point out that CE have almost uphold its initial performance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42310.
Cognitive Reflection Predicts Real‐Life Decision Outcomes, but Not Over and Above Personality and Decision‐Making Styles
Authors: Juanchich Marie , Dewberry Chris , Sirota Miroslav , Narendran Sunitha 
Published: May 2015

AbstractThe Cognitive Reflection Test (CRT), designed to assess the ability to inhibit intuition to process a problem analytically, predicts people's performance in many normative judgement and decision‐making tasks (e.g., Bayesian reasoning, conjunction fallacy and ratio bias). However, how the CRT predicts normative decision‐making performance is unclear, and little is known about the extent to which the CRT predicts real‐life decision outcomes. We investigate the role of the CRT in predicting real‐life decision outcomes and examine whether the CRT predicts real‐life decision outcomes after controlling for two related individual differences: the Big Five personality traits and decision‐making styles. Our results show that greater CRT scores predict positive real‐life decision outcomes measured by the Decision Outcome Inventory. However, the effect size was small, and the relationship became non‐significant after statistically controlling for personality and decision‐making styles. We discuss the limited predictive role of cognitive reflection in real‐life decision‐making outcomes, along with the roles of personality and decision‐making styles. Copyright © 2015 John Wiley & Sons, Ltd.
Influence of rurality, deprivation and distance from clinic on uptake in men invited for abdominal aortic aneurysm screening
Authors: Crilly M A , Mundie A , Bachoo P , Nimmo F 
Published: May 2015

AbstractBackgroundEffective abdominal aortic aneurysm (AAA) screening requires high uptake. The aim was to assess the independent association of screening uptake with rurality, social deprivation, clinic type, distance to clinic and season.MethodsScreening across Grampian was undertaken by trained nurses in six community and three hospital clinics. Men aged 65 years were invited for screening by post (with 2 further reminders for non-responders). AAA screening data are stored on a national call–recall database. The Scottish postcode directory was used to allocate to all invited men a deprivation index (Scottish Index of Multiple Deprivation), a Scottish urban/rural category and distance to clinic. Multivariable analysis was undertaken.ResultsThe cohort included 5645 men invited for screening over 12 months (October 2012 to October 2013); 42·6 per cent lived in urban areas, 38·9 per cent in rural areas and 18·5 per cent in small towns (uptake 87·0, 89·3 and 90·8 per cent respectively). Overall uptake was 88·6 per cent with 76 new AAAs detected: 15·2 (95 per cent c.i. 11·8 to 18·6) per 1000 men screened. Aberdeen city (large urban area) had the lowest uptake (86·1 per cent). Uptake declined with increasing deprivation, with the steepest decline in urban areas. On multivariable analysis, a 1-point increase in deprivation deciles was associated with a 0·08 (95 per cent c.i. 0·06 to 0·11) reduction in the odds of being screened (P &lt; 0·001). Clinic type (community versus hospital), distance to clinic and season were not associated independently with uptake.ConclusionBoth urban residence and social deprivation were associated independently with uptake among men invited for AAA screening.
Biomass‐Derived Porous Carbon Materials: Synthesis and Catalytic Applications
Authors: De Sudipta , Balu Alina Mariana , van der Waal Jan C. , Luque Rafael 
Published: May 2015

AbstractNovel biomass‐derived porous carbons are attractive candidates for the preparation of carbon‐supported catalysts with a wide range of catalytic applications. Such carbonaceous catalysts are environmentally benign and could provide a cost‐competitive advantage as compared to existing heterogeneous catalysts. Tunable surface properties of carbon materials and excellent physical properties (e.g., hydrophobicity, chemically inert nature, etc.) are compatible with diverse catalysis reactions including organic transformations, as well as electro‐ and photochemical processes in aqueous solutions. This contribution provides an overview on the utilization of different biomass feedstocks and/or biomass‐derived precursors for the synthesis of carbonaceous materials to design advanced catalytic systems and their emerging applications in catalysis.
Comparison of the Full Catalytic Cycle of Hydroformylation Mediated by Mono‐ and Bis‐Ligated Triphenylphosphine–Rhodium Complexes by Using DFT Calculations
Authors: Jacobs Ivo , de Bruin Bas , Reek Joost N. H. 
Published: May 2015

AbstractThe coordination mode of triphenylphosphine to rhodium is considered to be important for the outcome of hydroformylation catalysis. The difference in reactivity between mono‐ and bis‐ligated rhodium species has not been investigated systematically, mostly because it is impossible to obtain pure mono‐ligated rhodium under hydroformylation conditions. Therefore, we performed detailed computational studies to get an insight into the effect of the coordination of triphenylphosphine to rhodium on hydroformylation catalysis. The DFT‐calculated catalytic pathway of the monophosphine‐based catalyst shows a lower free energy barrier (24.5 kcal mol−1) compared to the pathway of the bisphosphine catalyst (28.9 kcal mol−1). This confirms that monophosphine catalysts have an intrinsically higher activity than bisphosphine catalysts and indicates that the rate enhancement seen with the tetraphenylporphyrin‐based catalyst reported by our group previously is at least partly due to the monocoordination enforced by this encapsulating ligand.
Complex Reaction Environments and Competing Reaction Mechanisms in Zeolite Catalysis: Insights from Advanced Molecular Dynamics
Authors: De Wispelaere Kristof , Ensing Bernd , Ghysels An , Meijer Evert Jan , Van Speybroeck Veronique 
Published: May 2015

AbstractThe methanol‐to‐olefin process is a showcase example of complex zeolite‐catalyzed chemistry. At real operating conditions, many factors affect the reactivity, such as framework flexibility, adsorption of various guest molecules, and competitive reaction pathways. In this study, the strength of first principle molecular dynamics techniques to capture this complexity is shown by means of two case studies. Firstly, the adsorption behavior of methanol and water in H‐SAPO‐34 at 350 °C is investigated. Hereby an important degree of framework flexibility and proton mobility was observed. Secondly, the methylation of benzene by methanol through a competitive direct and stepwise pathway in the AFI topology was studied. Both case studies clearly show that a first‐principle molecular dynamics approach enables unprecedented insights into zeolite‐catalyzed reactions at the nanometer scale to be obtained.
Cage‐like Copper(II) Silsesquioxanes: Transmetalation Reactions and Structural, Quantum Chemical, and Catalytic Studies
Authors: Bilyachenko Alexey N. , Dronova Marina S. , Yalymov Alexey I. , Lamaty Frédéric , Bantreil Xavier , Martinez Jean , Bizet Christelle , Shul'pina Lidia S. , Korlyukov Alexander A. , Arkhipov Dmitry E. , Levitsky Mikhail M. , Shubina Elena S. , Kirillov Alexander M. , Shul'pin Georgiy B. 
Published: May 2015

AbstractThe transmetalation of bimetallic copper–sodium silsesquioxane cages, namely, [(PhSiO1.5)10(CuO)2(NaO0.5)2] (“Cooling Tower”; 1), [(PhSiO1.5)12(CuO)4(NaO0.5)4] (“Globule”; 2), and [(PhSiO1.5)6(CuO)4(NaO0.5)4(PhSiO1.5)6] (“Sandwich”; 3), resulted in the generation of three types of hexanuclear cylinder‐like copper silsesqui‐ oxanes, [(PhSiO1.5)12(CuO)6(C4H9OH)2(C2H5OH)6] (4), [(PhSiO1.5)12(CuO)6(C4H8O2)4(PhCN)2(MeOH)4] (5), and [(PhSiO1.5)12(CuO)6(NaCl)(C4H8O2)12(H2O)2] (6). The products show a prominent “solvating system–structure” dependency, as determined by X‐ray diffraction. Topological analysis of cages 1–6 was also performed. In addition, DFT theory was used to examine the structures of the Cooling Tower and Cylinder compounds, as well as the spin density distributions. Compounds 1, 2, and 5 were applied as catalysts for the direct oxidation of alcohols and amines into the corresponding amides. Compound 6 is an excellent catalyst in the oxidation reactions of benzene and alcohols.
Iron‐Catalyzed C(sp2)H and C(sp3)H Methylations of Amides and Anilides
Authors: Graczyk Karolina , Haven Tobias , Ackermann Lutz 
Published: May 2015

AbstractThe so‐called magic methyl effect significantly boosts the bioactivities and physical properties of pharmacologically active drugs. Direct introduction of the methyl group by CH activation was accomplished with a versatile iron catalyst, which enabled the CH methylation of (hetero)benzamides, anilides, alkenes, and even alkanes by triazole assistance in a chemo‐, site‐ and diastereo‐selective fashion.
ChemInform Abstract: Three Alkali Metal Lead Orthophosphates ‐ Syntheses, Crystal Structures and Properties of APbPO4(A:K, Rb, Cs).
Authors: Huang Shengshi , Jing Qun , Han Jian , Pan Shilie , Wu Hongping , Yang Zhihua 
Published: May 2015

AbstractSingle crystals of the title compounds are prepared by solid state reactions of M2CO3 (M: K, Rb, Cs), PbO, PbF2, H3BO3, and (NH4)H2PO4 in a molar ratio of 2:5:5:4:3 (Pt crucible, 700 °C, 10 h).