bluuebunny/crossref_metadata_2025_split huggingface dataset:
ChemInform Abstract: Claisen‐Schmidt Condensation in Solvent‐Free Conditions via the Use of Microwave Irradiation and Pestle/Mortar.
Authors: Mogilaiah K. , Chandra A. Vinay , Praveena D. 
Published: January 2014

AbstractBoth the methods are attractive due to their simplicity, ease of workability, enhanced yields, reduced reaction time period and practical applicability.
ChemInform Abstract: N‐Heterocyclic Carbene‐Catalyzed Stereoselective Cascade Reaction: Synthesis of Functionalized Tetrahydroquinolines.
Authors: Zhang Hai‐Rui , Dong Zhen‐Wen , Yang Yu‐Jie , Wang Ping‐Luan , Hui Xin‐Ping 
Published: January 2014

AbstractThe construction of chiral functionalized tetrahydroquinolines with three consecutive stereogenic centers is achieved by the first NHC‐catalyzed stereoselective aza‐Michael‐Michael‐lactonization cascade reaction of aminophenylenones with bromoenals.
ChemInform Abstract: Stereoselective Amine Addition of Six‐Membered Cyclic Nitronates Promoted by Silyl Triflate.
Authors: Mikhaylov Andrey A. , Dilman Alexander D. , Khomutova Yulia A. , Arkhipov Dmitry E. , Korlyukov Alexander A. , Ioffe Sema L. 
Published: January 2014

AbstractThe reaction products occur in different conformations depending on the substitution pattern.
ChemInform Abstract: An Efficient One‐Pot Synthesis of Pyrazolyl‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazin‐6‐yl‐2H‐pyran‐2‐one Derivatives via Multicomponent Approach and Their Potential Antimicrobial and Nematicidal Activities.
Authors: Penta Santhosh , Gadidasu Kranthi Kumar , Basavoju Srinivas , Rao Vedula Rajeswar 
Published: January 2014

AbstractTitle compounds (IV) and (VI) are synthesized and evaluated for their in vitro antimicrobial activity against both gram‐positive and gram‐negative bacteria as well as their antifungal and nematicidal activity.
ChemInform Abstract: Potassium (E)‐Alkenylaryltrifluoroborates: Orthogonal Functionalization of Haloaryltrifluoroborates via Heck—Mizoroki Reaction.
Authors: Song Jung Ho , Kim Taejung , Lee Jae Wook , Moon Soo‐Yeon , Kim Won‐Suk , Ham Jungyeob 
Published: January 2014

AbstractThe target compounds are prepared from arylolefins or activated olefins.
ChemInform Abstract: Antimycobacterial Agent, (E)‐Phytol and Lauric Amide from the Plant Lagascea mollis.
Authors: Bhattacharya Asish K. , Rana Kalpeshkumar C. 
Published: January 2014

Abstractisolation and characterization of the antimycobacterial diterpene alcohol, (E)‐phytol (I), and lauric amide
ChemInform Abstract: A Facile Synthesis of N/C‐Terminal Selenourea Tethered Glycosylated Amino Acids
Authors: Sureshbabu Vommina V. , Vasantha B. , Madhu C. 
Published: January 2014

Abstractvia coupling of isoselenocyanates (II) or (IV) with O‐protected glycosylamines (I)
ChemInform Abstract: Practical Silyl Protection of Ribonucleosides.
Authors: Blaisdell Thomas P. , Lee Sunggi , Kasaplar Pinar , Sun Xixi , Tan Kian L. 
Published: January 2014

AbstractA selective silylation of the 3′‐ or 2′‐hydroxyl groups is achieved by choosing the enantiomer of the catalyst.
ChemInform Abstract: DNA Modification under Mild Conditions by Suzuki—Miyaura Cross‐Coupling for the Generation of Functional Probes.
Authors: Lercher Lukas , McGouran Joanna F. , Kessler Benedikt M. , Schofield Christopher J. , Davis Benjamin G. 
Published: January 2014

AbstractA new efficient method for Pd‐catalyzed Suzuki—Miyaura cross‐coupling to iododeoxyuridine in DNA is described.
ChemInform Abstract: Low‐Temperature Solution Processing of Mesoporous Metal—Sulfide Semiconductors as Light‐Harvesting Photoanodes.
Authors: O'Mahony Flannan T. F. , Cappel Ute B. , Tokmoldin Nurlan , Lutz Thierry , Lindblad Rebecka , Rensmo Haakan , Haque Saif A. 
Published: January 2014

AbstractMesoporous films of highly crystalline Sb2S3 are prepared from a precursor paste of Sb(S2CO‐Et)3, hexylamine, and chlorobenzene by annealing at 120 °C.
ChemInform Abstract: Nickel Dichalcogenide Hollow Spheres: Controllable Fabrication, Structural Modification, and Magnetic Properties.
Authors: Ma Wei , Guo Yanfeng , Liu Xiaohe , Zhang Dan , Liu Tao , Ma Renzhi , Zhou Kechao , Qiu Guanzhou 
Published: January 2014

AbstractNiS2 hollow spheres are hydrothermally synthesized from a mixture of Ni(NO3)2, L‐cysteine, urea, and H2O (autoclave, 140 °C, 24 h).
ChemInform Abstract: Complexes with Nitrogen‐Centered Radical Ligands: Classification, Spectroscopic Features, Reactivity, and Catalytic Applications
Authors: Suarez Alma I. Olivos , Lyaskovskyy Volodymyr , Reek Joost N. H. , van der Vlugt Jarl Ivar , de Bruin Bas 
Published: January 2014

AbstractReview: 106 refs.
Synthesis, Characterization and Cytotoxicity of (η6‐p‐cymene)ruthenium(II) Complexes of α‐Amino Acids
Authors: Egbewande Folake A. , Paul Lydia E. H. , Therrien Bruno , Furrer Julien 
Published: January 2014

AbstractArene ruthenium complexes of α‐amino acids, obtained by mixing aqueous solutions of [(η6‐p‐cymene)RuCl2]2in the presence of AgCF3SO3with various amino acids, have been studied at 37 °C using NMR spectroscopy and electrospray ionization mass spectrometry (ESI‐MS). Small hydrophobic α‐amino acid anions were found to form bidentateN,O‐chelate complexes, whereas α‐amino acids with coordinating side chains (e.g. serine, aspartic acid, histidine) acted as tridentate ligands. For many amino acids, more than two chelate complexes were formed. Presumably, complexes with the general formula [(η6‐p‐cymene)Ru(AA)2]n+and bridged complexes with the general formula [{(η6‐p‐cymene)Ru}2(μ‐AA)2(μ‐OH)]+were observed together with the expected bi‐ and tridentate chelate complexes. All complexes, isolated as triflate salts, were evaluated for their in vitro anticancer activity against the human ovarian cancer cell line A2780 and its cisplatin‐resistant mutant A2780cisR. All complexes were found to be highly cytotoxic, with IC50values ranging from 0.16–19.8 μM. Interestingly, all complexes were selectivity active against A2780 cells relative to the A2780cisR variants, indicating a distinct mechanism of action that differs from that of many previously reported cytotoxic ruthenium complexes. No direct correlation between the kinetics of complex formation and cytotoxicity was apparent, suggesting that other physicochemical parameters such as complex stability and ligand exchange kinetics may play important roles in the biological activity.
A Convenient Approach to N‐(Di‐tert‐butylphosphanyl)‐ and N‐(Di‐tert‐butylphosphoroselenoyl)formamidinium Salts: Carbene Precursors
Authors: Marchenko Anatoliy , Koidan Georgyi , Hurieva Anastasiya , Savateev Aleksandr , Rozhenko Alexander B. , Sotiropoulos Jean‐Marc , Shishkina Svitlana V. , Shishkin Oleg V. , Kostyuk Aleksandr 
Published: January 2014

AbstractThe reactions of (di‐tert‐butylphosphanyl)amines and P,P‐di‐tert‐butylphosphinoselenoic amides with Alder's dimer were studied. For di‐tert‐butylphosphanylamines, the reaction proceeds by primary electrophilic attack of Alder's dimer at the phosphorus atom to afford a dicationic salt 3. The deprotonation of 3 led to N‐phosphanylformamidine 5 (“phosfam”). Alkyl(di‐tert‐butylphosphanyl)amines reacted with Alder's dimer in a 2:1 molar ratio to give N‐phosphanylformamidinium salts; the second equivalent of (alkylamino)phosphane acts as a base. (Arylamino)phosphanes reacted with Alder's dimer to give benzazaphospholium derivatives. To direct the electrophilic attack of Alder's dimer at the nitrogen atom, phosphinoselenoic amides were used. They reacted with Alder's dimer at the selenium atom followed by a selenium–phosphorus shift to give N‐(di‐tert‐butylphosphoroselenoyl)formamidinium salts. The phosphinoselenoic amides with bulky substituents (adamantyl, tBu) underwent cleavage of the N–alkyl bond to afford phosfams. Various key intermediates such as 3 and 22b were isolated and characterized. A convenient method for the synthesis of carbene precursor PIII and PV N‐substituted formamidinium salts was developed.
Theoretical Study of Thorium and Uranium Tetracarbide Molecules
Authors: Pogány Peter , Kovács Attila , Konings Rudy J. M. 
Published: January 2014

AbstractThe electronic structure and ground‐state molecular properties of neutral Th and U tetracarbides were investigated by relativistic multireference calculations using complete active space self‐consistent field/multiconfiguration second‐order perturbation theory (CASSCF/CASPT2) with an all‐electron basis set as well as by density functional theory (B3LYP) in conjunction with relativistic pseudopotentials. The former calculations were extended with complete active space state interaction (CASSI) calculations accounting for spin–orbit coupling. The four carbon atoms can be arranged in various forms around the actinide atom to result in ten structural isomers found altogether in our study. The electronic ground state in both molecules corresponds to a planar fan‐type structure of C2v symmetry, in which the actinide atom is connected to a bent C4 moiety. Three structures arise from various arrangements of C2 moieties around the Th and U, whereas six isomers contain a C3 moiety and a lone C bonded to the actinide. The latter CAnC3‐type structures are very high‐energy structures (over 200 kJ mol–1 with respect to the ground state). The bonding characteristics in the most relevant structures were analysed on the basis of the valence molecular orbitals and the natural bond orbital method. We evaluated and interpreted the vibrational and electronic spectra. The present computed data for UC4 suggest a revision of the assignment of a previously observed IR absorption band to a different isomer.
A Catalyst with Two‐Coordinate Nickel: Theoretical and Catalytic Studies
Authors: Mondal Kartik Chandra , Samuel Prinson P. , Li Yan , Roesky Herbert W. , Roy Sudipta , Ackermann Lutz , Sidhu Navdeep S. , Sheldrick George M. , Carl Elena , Demeshko Serhiy , De Susmita , Parameswaran Pattiyil , Ungur Liviu , Chibotaru Liviu F. , Andrada Diego M. 
Published: January 2014

AbstractThe bisadduct (cAAC)2NiIICl2 [1; cAAC = cyclic (alkyl)(amino)carbene] was directly synthesized by treating cAAC with NiCl2. Compound 1 was reduced to (cAAC)2Ni0 (2) by using lithium diisopropylamide or KC8. Crystals of 2 were stable under an inert gas for several months and decomposed upon heating above 165 °C. On the basis of the calculated natural bond orbital charge values of the nickel atom in 2, the oxidation state of nickel was determined to be between NiI and Ni0 (+0.34). Theoretical calculations suggested a closed‐shell singlet electronic configuration of 2 with little biradical character. Ab initio multiconfigurational C(R)ASSCF/CASPT2 calculations predicted a closed‐shell singlet electronic configuration (Ni0), whereas excited spin states possessed NiI character with unpaired electrons on neighboring carbon atoms. The catalytic activity of complex 2 was investigated for the homocoupling of various unactivated aryl chlorides/fluorides. The biaryls were obtained in good yields at moderate temperature. Theoretical studies showed that an intermediate containing NiIII was more favored than one with NiIV.
A Convergent Strategy for the Synthesis of Second‐Generation Iminosugar Clusters Using “Clickable” Trivalent Dendrons
Authors: Joosten Antoine , Schneider Jérémy P. , Lepage Mathieu L. , Tarnus Céline , Bodlenner Anne , Compain Philippe 
Published: January 2014

AbstractA convergent strategy to access high‐valency iminosugar clusters based on two successive CuI‐catalysed azide–alkyne cycloadditions is reported. The key step of this approach relies on the grafting of azide‐armed trivalent iminosugar dendrons onto polyalkyne “clickable” scaffolds, thus tripling their initial valency. As a proof of concept, the synthesis of cyclodextrin‐based clusters containing the highest number of peripheral iminosugar ligands reported to date has been achieved. Evaluation of these compounds as mannosidase inhibitors revealed one of the strongest multivalent effects observed so far in glycosidase inhibition.
Synthesis of Tetrasubstituted Olefins by Palladium‐Catalyzed Double Heck Cycli­zation of Bromoenynes
Authors: Naveen Kanagaraj , Muralidharan Doraiswamy , Perumal Paramasivan Thirumalai 
Published: January 2014

AbstractPalladium‐catalyzed regio‐ and stereoselective synthesis of tetrasubstituted olefins incorporating an indene scaffold was developed through 6‐exo‐dig carbocyclization followed by Heck cyclization with anti β‐hydrogen elimination. The starting materials for the domino reaction were designed through an A3‐coupling reaction.
An assessment of biodegradability of quaternary carbon–containing fragrance compounds: Comparison of experimental OECD screening test results and in silico prediction data
Authors: Seyfried Markus , Boschung Alain 
Published: January 2014

Abstract

An assessment of biodegradability was carried out for fragrance substances containing quaternary carbons by using data obtained from Organisation for Economic Co-operation and Development (OECD) 301F screening tests for ready biodegradation and from Biowin and Catalogic prediction models. Despite an expected challenging profile, a relatively high percentage of common-use fragrance substances showed significant biodegradation under the stringent conditions applied in the OECD 301F test. Among 27 test compounds, 37% met the pass level criteria after 28 d, while another 26% indicated partial breakdown (≥20% biodegradation). For several compounds for which structural analogs were available, the authors found that structures that were rendered less water soluble by either the presence of an acetate ester or the absence of oxygen tended to degrade to a lesser extent compared to the primary alcohols or oxygenated counterparts under the test conditions applied. Difficulties were encountered when attempting to correlate experimental with in silico data. Whereas the Biowin model combinations currently recommended by regulatory agencies did not allow for a reliable discrimination between readily and nonbiodegradable compounds, only a comparably small proportion of the chemicals studied (30% and 63% depending on the model) fell within the applicability domain of Catalogic, a factor that critically reduced its predictive power. According to these results, currently neither Biowin nor Catalogic accurately reflects the potential for biodegradation of fragrance compounds containing quaternary carbons. Environ Toxicol Chem 2014;33:1005–1016. © 2014 SETAC
New phase‐based B1 mapping method using two‐dimensional spin‐echo imaging with hyperbolic secant pulses
Authors: Lee Yoojin , Han Yeji , Park HyunWook , Watanabe Hidehiro , Garwood Michael , Park Jang‐Yeon 
Published: January 2014

PurposeTo propose a new phase‐based B1‐mapping method that exploits phase information created by hyperbolic secant (HS) pulses in conventional 2D spin‐echo imaging.MethodsIn this B1‐mapping method, HS pulses are used to accomplish π/2 excitation and π refocusing in standard multislice spin‐echo imaging. When setting the ratio of pulse lengths of the π/2 and π HS pulses to 2:1, the spin‐echo phase is independent of offset frequency and varies as a function of B1 strength. To eliminate undesired phase accumulations induced by unknown factors other than the B1 strength, two spin‐echo images are acquired using HS pulses applied with opposite frequency‐sweep directions, and the resulting phase images are subtracted from each other. To demonstrate the performance of the proposed method, phantom and in vivo experiments were performed using a surface coil and a volume coil.ResultsThe B1 maps obtained by using the proposed method were in accordance with the B1 maps obtained using previous methods in both phantom and in vivo experiments.ConclusionThe proposed method is easy to implement without any sequence modification, is insensitive to B0 inhomogeneity and chemical shift, and is robust in a reasonably wide range of B1 field strength. Magn Reson Med 73:170–181, 2015. © 2014 Wiley Periodicals, Inc.
Modelling the potential distribution of Bemisia tabaci in Europe in light of the climate change scenario
Authors: Gilioli Gianni , Pasquali Sara , Parisi Simone , Winter Stephan 
Published: January 2014

AbstractBACKGROUNDBemisia tabaci is a serious pest of agricultural and horticultural crops in greenhouses and fields around the world. This paper deals with the distribution of the pest under field conditions. In Europe, the insect is currently found in coastal regions of Mediterranean countries where it is subject to quarantine regulations. To assess the risk presented by B. tabaci to Europe, the area of potential establishment of this insect, in light of the climate change scenario, was assessed by a temperature‐dependent physiologically based demographic model (PBDM).RESULTSThe simulated potential distribution under current climate conditions has been successfully validated with the available field records of B. tabaci in Europe. Considering climate change scenarios of +1 and +2 °C, range expansion by B. tabaci is predicted, particularly in Spain, France, Italy, Greece and along the Adriatic coast of the Balkans. Nonetheless, even under the scenario of +2 °C, northern European countries are not likely to be at risk of B. tabaci establishment because of climatic limitations.CONCLUSIONModel validation with field observations and evaluation of uncertainties associated with model parameter variability support the reliability of model results. The PBDM developed here can be applied to other organisms and offers significant advantages for assessing the potential distribution of invasive species. © 2014 Society of Chemical Industry
Interaction of protamine with gram‐negative bacteria membranes: possible alternative mechanisms of internalization in Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa
Authors: Pink David. A. , Hasan Fida M. , Quinn Bonnie E. , Winterhalter Mathias , Mohan Mukund , Gill Tom A. 
Published: January 2014

This study was concerned with the interaction between the cationic antimicrobial peptide, protamine (Ptm) and the cytoplasmic membranes of the gram‐negative bacteria Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa. The objective of the study was to explain the observed paradox of internalization without permanent disruption of the cell envelope. We carried out Monte Carlo computer simulation of Ptm in an aqueous environment in the presence of ~100 mM NaCl and model membranes consisting of either (65:35) or (75:25) PE:PG molar ratios. The (75:25) model, representative of the gram‐negative cytoplasmic membrane, showed that the Ptm center of mass remained at least 7 nm from the membrane surface leading to the prediction that Ptm would not internalize via disruption of the inner membrane.By using immunoelectron microscopy of Ptm‐treated cells, we showed that Ptm internalization to the cytoplasm took place rapidly in the presence or absence of the outer envelope. Ultrastructural examination revealed no obvious morphological changes to cells that were treated with subinhibitory or bactericidal levels of Ptm. Reconstituted phospholipid bilayers were constructed and were unperturbed by Ptm treatment over a wide range of concentrations and applied transmembrane voltages. We conclude that in the cases of the cell envelopes of E. coli, S. typhimurium and P. aeruginosa, Ptm internalized by means independent of the phospholipid bilayer, most likely mediated by one or more membrane proteins such as cation‐selective barrel‐like proteins. Work is currently underway to test this hypothesis. © 2014 The Authors. Journal of Peptide Science published by John Wiley & Sons, Ltd.
Measurement of electric field enhanced optical absorption in hydrogenated amorphous silicon
Authors: Pirc Matija , Furlan Jože , Levstek Andrej , Topič Marko 
Published: January 2014

AbstractOptical properties of amorphous semiconductors are influenced by applied or built‐in electric fields. Measurements of the optical absorption change of device grade intrinsic hydrogenated amorphous silicon were performed indirectly by measuring the optical transmission of the samples with and without an applied DC electric field. Effects of ambient temperature changes were limited by strict control of the ambient temperature. Temperature effects caused by self‐heating of the samples were compensated in two different ways to ensure the validity of the results. The influence of temperature change on optical absorption was identified and compensated by the analysis of measurements of multiple samples with different levels of power dissipation brought about by sample conductivity variations. The second method of temperature compensation consisted of determining the temperature change of each sample during the measurements, modelling absorption coefficient change caused by the temperature change and by subtracting the calculated absorption change caused by the temperature change from the measured absorption change. Results of both methods of temperature compensation are in good agreement. The obtained results are also in agreement with the results of other researchers up to photon energies slightly above the mobility edge, where our measurements exhibit a slightly different dependency on photon energy than previously published measurements. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of carrier injection in Si nanoparticle‐SiOx film based MOS devices
Authors: Jacques E. , Pichon L. , Labbe C. , Khomenkova L. , Gourbilleau F. 
Published: January 2014

AbstractThe electrical properties of silicon rich oxide (SRO) layers integrated in metal‐oxide‐semiconductor device are analysed. The layers are deposited using the magnetron co‐sputtering of a pure SiO2 and Si targets under a pure argon plasma. Each SRO layer embedding silicon nanoparticles (Si‐np‐SiOx) was subsequently submitted to an optimized annealing treatment. Three types of Al/Si‐np‐SiOx/p‐Si devices are fabricated with different incorporated silicon excesses (9, 11, or 16 at.%) in the active layer. Analysis of static electrical properties of the devices showed a semi‐resistive behaviour for each device. Carrier injection into the SiOx matrix in terms of Poole‐Frenkel and Fowler‐Nordheim mechanisms is analysed in relation with the incorporated silicon excess. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structures with two‐dimensional distributed feedback for a laser realization on Si:Er basis
Authors: Stepikhova Margarita , Baryshev Vladimir , Ginzburg Naum , Vdovichev Sergey , Gribkov Boris , Klimov Alexander , Krasilnik Zachary 
Published: January 2014

AbstractUsing 2D distributed feedback (DFB) exploiting 2D Bragg resonators for a Si:Er lasers is suggested. Self excitation conditions are defined analytically. Numerical simulation of the nonlinear dynamics demonstrates that 2D DFB can provide synchronization of radiation for wide active media. A test laser‐like Si/SOI structure is fabricated and described. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental investigations on the punching behaviour of reinforced concrete footings with structural dimensions
Authors: Siburg Carsten , Hegger Josef 
Published: January 2014

AbstractPunching tests on 13 specimens under uniform soil pressure were conducted to evaluate the punching shear behaviour of footings with practical dimensions. The test series included square footings with and without punching shear reinforcement. The dimensions of the footings varied between 1.20 × 1.20 m and 2.70 × 2.70 m and the slab thickness varied between 0.45 and 0.65 m, resulting in shear span‐depth ratios aλ/d between approx. 1.25 and 2.00.In addition to the measured steel strains in the flexural reinforcement and the stirrups, the increase in the slab thickness as well as the saw‐cuts were examined to investigate the internal cracking and failure characteristic. In combination with previous tests conducted at RWTH Aachen University, this test series permits a description of the effect of the main parameters on the punching shear strength of footings. These parameters are the size effect of the effective depth, the concrete compressive strength, the flexural reinforcement ratio and the punching shear reinforcement.