bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transport Effects ‐ Homogeneous
Authors: Garland Marc 
Published: March 2010

AbstractIn the present contribution, the effects of different types of mass‐transfer on homogeneous catalytic reactions are addressed. In particular, emphasis is given to the effects of mass‐transfer on the precatalytic reactions as well as the turnover frequency. Various types of transport effects are considered. These include gas–liquid and liquid–liquid mass transfer, segregation and mixing of solutions, as well as dissolution kinetics of sparingly soluble organometallics and cage effects. A number of criteria are suggested for comparing the rates of mass transfer with various rates of reaction. A checklist is proposed for the experimentalist to assist in identifying potential mass‐transfer control issues. Simple steps to mitigate these complications are suggested.
How Catalysts Affect the Growth of Single‐Walled Carbon Nanotubes on Substrates
Authors: Li Yan , Cui Rongli , Ding Lei , Liu Yu , Zhou Weiwei , Zhang Yan , Jin Zhong , Peng Fei , Liu Jie 
Published: March 2010

AbstractDirect growth of single‐walled carbon nanotubes (SWNTs) on flat substrates by chemical vapor deposition (CVD) is very important for the application of SWNTs in nanodevices. In the growth process, catalysts play an important role in controlling the structure of SWNTs. Over the years, we have systematically studied the size‐controlled synthesis of Fe‐based nanoparticles and the CVD growth of SWNTs, especially the horizontally aligned SWNTs, catalyzed by these produced nanoparticles. Some new catalysts were also developed. Among them, Cu is shown to be a superior catalyst for growing SWNT arrays on both silicon and quartz substrates and Pb is a unique catalyst from which one can obtain SWNTs without any metallic contaminant. SWNTs prepared with both Cu and Pb are very suitable for building high‐performance nanodevices. These studies are also very helpful for further understanding the growth mechanism of SWNTs.
Facile Creation of 3‐Indolyl‐3‐hydroxy‐2‐oxindoles by an Organocatalytic Enantioselective Friedel–Crafts Reaction of Indoles with Isatins
Authors: Deng Jing , Zhang Shilei , Ding Peng , Jiang Hualiang , Wang Wei , Li Jian 
Published: March 2010

AbstractThe first direct enantioselective Friedel–Crafts reaction of indoles with isatins has been developed. The process is catalyzed by simple cupreine under mild reaction conditions and affords synthetically and biologically interesting, chiral 3‐indolyl‐3‐hydroxy‐2‐oxindoles in good yields (68–97%) and with high enantioselectivities (76–91%).
Mycophagy and its influence on habitat use and ranging patterns in Callimico goeldii
Authors: Porter Leila M. , Garber Paul A. 
Published: March 2010

AbstractMycophagy has been documented in a number of species of marmosets and lion tamarins (Callitrichinae) but its effect on ranging behavior is not known. We present the results of 10 years of research on five groups of Goeldi's monkey (Callimico goeldii) at a field site in northwestern Bolivia. We studied the diet and ranging behavior of two of the groups. On average, groups contained 4.5 individuals (range 2.0–9.0), but they gradually decreased in size until only the breeding female remained in the home range. The annual diet was composed of fungi (31.1–34.9%), fruits (34.0–40.6%), prey (17.4–30.1%), and exudates (1.0–10.9%). They had large home ranges (114–150 ha) and over time individuals tended to shift their core areas of use. They used secondary and bamboo forest and forest with dense understories more than expected based on availability. We suggest that the large home ranges and shifting core areas used by C. goeldii are components of a foraging strategy to track patchy, low density, and ephemeral fungal fruiting bodies. Our results, along with data published on other callitrichines, indicate that groups of Leontopithecus, Callithrix, and Callimico that eat fungi have larger home ranges than those that do not. Mycophagy is one of the several factors that evidently affect home range size in callitrichines. Fungi are clearly an important food source for a number of populations, but additional studies are needed to determine why some eat fungi frequently while others do not. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.
Asymmetrische Organokatalyse mit Sulfonen
Authors: Nielsen Martin , Jacobsen Christian Borch , Holub Nicole , Paixão Marcio Weber , Jørgensen Karl Anker 
Published: March 2010

AbstractDie asymmetrische Organokatalyse hat sich zu einer effektiven Methode für die Herstellung optisch aktiver Verbindungen entwickelt. Während sich erste Untersuchungen im Wesentlichen auf die Verwendung einfacher Reagentien als Nachweis der Realisierbarkeit konzentrierten, befassen sich neuere Studien der asymmetrischen Organokatalyse nun damit, das Konzept auf ziel‐ und diversitätsorientierte Synthesen zu erweitern. Dank ihrer zahlreichen Transformationsmöglichkeiten und ihrer Fähigkeit zur Generierung nucleophiler wie auch elektrophiler Reaktionspartner spielen dabei Sulfone als Substrate eine besondere Rolle in der Organokatalyse.
To Protonate or Alkylate? Stereoselective Brønsted Acid Catalysis of CC Bond Formation Using Diazoalkanes
Authors: Johnston Jeffrey N. , Muchalski Hubert , Troyer Timothy L. 
Published: March 2010

AbstractA new means to activate diazoalkanes has been discovered and applied broadly over the past few years. Brønsted acids, both achiral and chiral, have been used to promote the formation of carbon–carbon and carbon–heteroatom bonds with a growing number of diazoalkane derivatives. Aside from their straightforward ability to build structural and stereochemical complexity in innovative new ways, these transformations are remarkable owing to their ability to skirt competitive diazo protonation—a reaction that has long been used to prepare esters efficiently and cleanly from carboxylic acids. In cases where achiral Brønsted acids are used, high diastereoselection can be achieved. Meanwhile, chiral Brønsted acids can deliver products with both high diastereo‐ and enantioselectivity. More recently, systems have emerged that combine Brønsted acids and either Lewis acids or transition metals to promote carbon–carbon bond formation from diazoalkanes.
Asymmetric Organocatalysis with Sulfones
Authors: Nielsen Martin , Jacobsen Christian Borch , Holub Nicole , Paixão Marcio Weber , Jørgensen Karl Anker 
Published: March 2010

AbstractAsymmetric organocatalysis has become a powerful tool for the synthesis of optically active compounds. Whereas early research mainly focused on combining simple reagents as a proof‐of‐concept for asymmetric organocatalysis, recent investigations are directed towards extending the concept to more target‐ and diversity‐oriented synthesis. As a result of the many transformation possibilities and their ability to generate both nucleophilic and electrophilic reaction partners, sulfones have become especially important substrates in the field of organocatalysis.
Synthesis, characterization and single crystal structure determination of aluminum alkoxydisilanolates: precursors for silica–alumina composite
Authors: Amini Mostafa M. , Mohammadnezhad Gholamhossein , Mirzaee Mehdi , Khavasi Hamid Reza 
Published: March 2010

AbstractSeveral novel aluminum alkoxydisilanolate complexes were prepared by reaction of triphenylsilanol with aluminum 2‐methoxyethoxide, aluminum 2‐ethoxyethoxide, aluminum sec‐butoxide and aluminum iso‐propoxide. All new complexes, [(Ph3SiO)2Al(OR)]2 [where R = CH2CH2OCH3 (1), CH2CH2OC2H5 (2), CH(CH3)CH2CH3 (3) and CH(CH3)2 (4)] were characterized by elemental analysis, mass spectrometry and infrared spectroscopy (IR), as well as 1H, 13C, 29Si and 27Al NMR spectroscopies. The solid‐state structures of the representative compound 2 and 4 were also verified by single‐crystal X‐ray analyses. Complexes 2 and 4 are dimers having distorted trigonal bipyramidal and tetrahedral coordination at the aluminum center, respectively. The 27Al NMR spectrum of compound 2 showed that the solid‐state structure of the complex was not retained in solution, and tetracoordinated aluminum was found in solution in contrast to the pentacoordinated geometry in the solid state. The hydrothermal treatment of 1 and 4 at 200 °C and the subsequent calcination at 1000 °C resulted in the formation of alumina–silica composite (4SiO2·Al2O3) with γ‐alumina in the silica matrix. Copyright © 2010 John Wiley & Sons, Ltd.
Discovery and Syntheses of “Superbug Challengers”—Platensimycin and Platencin
Authors: Palanichamy Kalanidhi , Kaliappan Krishna P. 
Published: March 2010

AbstractBacteria have developed resistance to almost all existing antibiotics known today and this has been a major issue over the last few decades. The search for a new class of antibiotics with a new mode of action to fight these multiply‐drug‐resistant strains, or “superbugs”, allowed a team of scientists at Merck to discover two novel antibiotics, platensimycin and platencin using advanced screening strategies, as inhibitors of bacterial fatty acid biosynthesis, which is essential for the survival of bacteria. Though both these antibiotics are structurally related, they work by slightly different mechanisms and target different enzymes conserved in the bacterial fatty acid biosynthesis. This Focus Review summarizes the synthetic and biological aspects of these natural products and their analogues and congeners.
Modified [(IPr)Pd(R‐acac)Cl] Complexes: Influence of the acac Substitution on the Catalytic Activity in Aryl Amination
Authors: Marion Nicolas , Navarro Oscar , Stevens Edwin D. , Ecarnot Elise C. , Bell Andrew , Amoroso Dino , Nolan Steven P. 
Published: March 2010

AbstractThe synthesis of a series of [(IPr)Pd(R‐acac)Cl] precatalysts (acac=acetylacetonato; IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene), where the acac ligand on palladium has been systematically modified through terminal substitution, is reported. The following substituted acac ligands are employed in this study: dibenzoylmethanato (dbm), benzoylacetonato (bac), tetramethylheptanedionato (tmhd), and hexafluoroacetylacetonato (hfac). Full spectroscopic characterization of the new complexes is provided along with X‐ray studies for three of these. Investigation of their catalytic activity in cross‐coupling is also presented through a comparative study in an aryl amination reaction. The catalytic results show a strong correlation between the increased steric bulk of the acac substituents and an increased activation rate of the precatalyst, going from the acac to the tmhd ligand. This observation, along with the inertness of the hfac compound, seems to support our previous proposal for the activation mechanism of these complexes under cross‐coupling conditions.
Rational Design of Pseudozyma antarctica Lipase B Yielding a General Esterification Catalyst
Authors: Liu Danni , Trodler Peter , Eiben Sabine , Koschorreck Katja , Müller Monika , Pleiss Jürgen , Maurer Steffen C. , Branneby Cecilia , Schmid Rolf D. , Hauer Bernhard 
Published: March 2010

AbstractPseudozyma antarctica lipase B (CALB) shows activity in the acrylation of hydroxypropylcarbamate, a racemic mixture of enantiomers of primary and secondary alcohols. However, full conversion is hampered by the slowly reacting S enantiomer of the secondary alcohol. The same is true for a wide range of secondary alcohols, for example, octan‐2‐ and ‐3‐ol. In order to get high conversion in these reactions in a short time, the stereospecificity pocket of CALB was redesigned by using predictions from molecular modeling. Positions 278, 104, and 47 were targeted, and a library for two‐site saturation mutagenesis at positions 104 and 278 was constructed. The library was then screened for hydrolysis of acrylated hydroxypropylcarbamates. The best mutants L278A, L278V, L278A/W104F, and L278A/W104F/S47A showed an increased conversion in hydrolysis and transesterification of more than 30 %. While the wild‐type showed only 73 % conversion in the acrylation of hydroxypropylcarbamate after 6 h, 97 % conversion was achieved by L278A in this time. Besides this, L278A/W104F reached >96 % conversion in the acrylation of octan‐2‐ and ‐3‐ol within 48 h and showed a significant decrease in stereoselectivity, while the wild‐type reached only 68 and 59 % conversion, respectively. Thus the new biocatalysts can be used for efficient transformation of racemic alcohols and esters with high activity when the high stereoselectivity of the wild‐type hampers complete conversion of racemic substrates in a short time.
Gramicidin S Derivatives Containing cis‐ and trans‐Morpholine Amino Acids (MAAs) as Turn Mimetics
Authors: Kapoerchan Varsha V. , Spalburg Emile , de Neeling Albert. J. , Mars‐Groenendijk Roos H. , Noort Daan , Otero José M. , Ferraces‐Casais Patricia , Llamas‐Saiz Antonio L. , van Raaij Mark J. , van Doorn Joop , van der Marel Gijs A. , Overkleeft Herman S. , Overhand Mark 
Published: March 2010

AbstractThe cyclic decapeptide gramicidin S (GS) was used as a model for the evaluation of four turn mimetics. For this purpose, one of the D‐Phe‐Pro two‐residue turn motifs in the rigid cyclic β‐hairpin structure of GS was replaced with morpholine amino acids (MAA 2–5), differing in stereochemistry and length of the side‐chain. The conformational properties of the thus obtained GS analogues (6–9) was assessed by using NMR spectroscopy and X‐ray crystallography, and correlated with their biological properties (antimicrobial and hemolytic activity). We show that compound 8, containing the dipeptide isostere trans‐MAA 4, has an apparent high structural resemblance with GS and that its antibacterial activity against a panel of Gram positive and ‐negative bacterial strains is better than the derivatives 6, 7 and 9.
Direct Synthesis of Titanium Complexes with Chelating cis‐9,10‐Dihydrophenanthrenediamide Ligands through Sequential CC Bond‐Forming Reactions from o‐Metalated Arylimines
Authors: Zhao Dapeng , Gao Wei , Mu Ying , Ye Ling 
Published: March 2010

AbstractA series of new titanium(IV) complexes with o‐metalated arylimine and/or cis‐9,10‐dihydrophenanthrenediamide ligands, [o‐C6H4(CHNR)TiCl3] (R=2,6‐iPr2C6H3 (3 a), 2,6‐Me2C6H3 (3 b), tBu (3 c)), [cis‐9,10‐PhenH2(NR)2TiCl2] (PhenH2=9,10‐dihydrophenanthrene; R=2,6‐iPr2C6H3 (4 a), 2,6‐Me2C6H3 (4 b), tBu (4 c)), [{cis‐9,10‐PhenH2(NR)2}{o‐C6H4(HCNR)}TiCl] (R=2,6‐iPr2C6H3 (5 a), 2,6‐Me2C6H3 (5 b), tBu (5 c)), have been synthesised from the reactions of TiCl4 with o‐C6H4(CHNR)Li (R=2,6‐iPr2C6H3, 2,6‐Me2C6H3, tBu). Complexes 4 and 5 were formed unexpectedly from the reactions of TiCl4 with two or three equivalents of the corresponding o‐C6H4(CHNR)Li followed by sequential intramolecular CC bond‐forming reductive elimination and oxidative coupling reactions. Attempts to isolate the intermediates, [{o‐C6H4(CHNR)}2TiCl2] (2), were unsuccessful. All complexes were characterised by 1H and 13C NMR spectroscopy, and the molecular structures of 3 a, 4 a–c, 5 a, and 5 c were determined by X‐ray crystallography.
Enantioselective Organocatalytic Addition of Oxazolones to 1,1‐Bis(phenylsulfonyl)ethylene: A Convenient Asymmetric Synthesis of Quaternary α‐Amino Acids
Authors: Alba Andrea‐Nekane R. , Companyó Xavier , Valero Guillem , Moyano Albert , Rios Ramon 
Published: March 2010

AbstractA new, easy, and highly enantioselective method for the synthesis of quaternary α‐alkyl‐α‐amino acids based on organocatalysis is reported. The addition of oxazolones to 1,1‐bis(phenylsulfonyl)ethylene is efficiently catalyzed by simple chiral bases or thioureas. The reaction affords α,α‐disubstituted α‐amino acid derivatives with complete C4 regioselectivity and with excellent yields and enantioselectivities. This methodology is complementary to previously reported enantioselective approaches to quaternary α‐amino acids and allows the synthesis of α‐phenyl‐α‐alkyl‐α‐amino acids and α‐tert‐butyl‐α‐alkyl‐α‐amino acids. It has distinct advantages in terms of operational simplicity, enviromentally friendly conditions, and suitability for large‐scale reactions.
Preparation and Characterisation of Super‐Hydrophobic Surfaces
Authors: Crick Colin R. , Parkin Ivan P. 
Published: March 2010

AbstractThe interest in highly water‐repellent surfaces has grown in recent years due to the desire for self‐cleaning surfaces. A super‐hydrophobic surface is one that achieves a water contact angle of 150° or greater. This article explores the different approaches used to construct super‐hydrophobic surfaces and identifies the key properties of each surface that contribute to its hydrophobicity. The models used to describe surface interaction with water are considered, with attention directed to the methods of contact angle analysis. A summary describing the different routes to hydrophobicity is also given.
An Efficient Low‐Temperature Stille–Migita Cross‐Coupling Reaction for Heteroaromatic Compounds by Pd–PEPPSI–IPent
Authors: Dowlut Meenakshi , Mallik Debasis , Organ Michael G. 
Published: March 2010

AbstractThe reactivity of Pd–PEPPSI (Pyridine, Enhanced, Precatalyst, Preparation, Stabilization, and Initiation) precatalysts in the Stille–Migita cross‐coupling reaction between heteroaryl stannanes and aryl or heteroaryl halides was evaluated. In general, Pd–PEPPSI–IPent (IPent=diisopentylphenylimidazolium derivative) demonstrated high efficiency over a variety of challenging aryl or heteroaryl halides with thiophene‐, furan‐, pyrrole‐, and thiazole‐based organostannanes when compared with Pd–PEPPSI–IPr (IPr=diisopropylphenylimidazolium derivative). The transformations proceeded at appreciably lower temperatures (30–80 °C) than triarylphosphine‐based Pd catalysts, improving the scope of this useful carbon–carbon bond‐forming process.
Binding and Inhibition of Copper Ions to RecA Inteins from Mycobacterium tuberculosis
Authors: Zhang Liyun , Xiao Ning , Pan Yan , Zheng Yuchuan , Pan Zhiyun , Luo Zhaofeng , Xu Xiaolong , Liu Yangzhong 
Published: March 2010

AbstractProtein splicing is a unique post‐translational process in which an intein excises itself from a precursor with the concomitant ligation of flanking sequences. The binding of zinc to intein inhibits protein splicing reversibly and EDTA relieves the inhibition. Copper was found to inhibit protein trans splicing; however, the recovery of intein splicing required both EDTA and TCEP, suggesting a different inhibition mechanism for copper compared to zinc. In this work, we have investigated the binding properties and inhibition effects of copper ions on the RecA intein from Mycobacterium tuberculosis. Both Cu+ and Cu2+ exhibited high binding affinity to inteins, while different binding sites were identified. Cu2+ coordinates to Cys1, the key residue involved in the mechanism of protein splicing, however, Cu+ does not coordinate to cysteine. An in vitro inhibition assay indicated that monovalent Cu+ demonstrates reversible inhibition to protein splicing, and the inhibitory efficiency is comparable to Zn2+. Redox reaction between Cu2+ and cysteine in inteins were observed and the rate constants were determined. The results suggested a dual role for Cu2+ in the inhibition of intein splicing: strong coordination of Cu2+ to key residues (including Cys1) in the intein, and subsequent oxidation of Cys1, the residue required for the N→S acyl shift step in protein splicing. A kinetic study suggested that the coordination could be the major cause of inhibition effect of Cu2+ initially, whereas the redox reaction could play an additional role in inhibition at a later stage.
ChemInform Abstract: Analysis of Electronic Structures and Chemical Bonding of Metal‐Rich Compounds. Part 2. Presence of Dimer (T—T)4‐ and Isolated T2‐ Anions in the Polar Intermetallic Cr5B3‐Type Compounds AE5T3 (AE: Ca, Sr; T: Au, Ag, Hg, Cd, Zn).
Authors: Lee Changhoon , Whangbo Myung‐Hwan , Koehler Juergen 
Published: March 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Structure and Charge Density Analysis of Ca(BH4)2.
Authors: Noritake T. , Aoki M. , Matsumoto M. , Miwa K. , Towata S. , Li H.‐W. , Orimo S. 
Published: March 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Structure and Photoluminescence Properties of Strong Blue‐Emitting Alumina Film Developed from a Liquid Sol at Low Temperature.
Authors: Peng Cheng‐Hsiung , Hwang Chyi‐Ching , Hsiao Chi‐Sheng 
Published: March 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Effect of Co‐Doping with Sm3+, Bi3+, La3+, and Nd3+ on the Electrochemical Properties of Hydrothermally Prepared Gadolinium‐Doped Ceria Ceramics.
Authors: Dikmen Sibel 
Published: March 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Simple Solid Oxide Fuel Cells.
Authors: Lin Bin , Wang Songlin , Liu Xingqin , Meng Guangyao 
Published: March 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Size Effects in the Li4+xTi5O12 Spinel.
Authors: Borghols W. J. H. , Wagemaker M. , Lafont U. , Kelder E. M. , Mulder F. M. 
Published: March 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Hydrogen Absorption in the Intermetallic Compounds Zr2TM (TM: Cu, Ag and Au) with MoSi2‐Type Structure (C11b).
Authors: Endo Naruki , Kameoka Satoshi , Tsai An Pang , Lingling Zou , Hirata Toshiya , Nishimura Chikashi 
Published: March 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Enhanced Catalytic Hydrogen Release of LiBH4 by Carbon‐Supported Pt Nanoparticles.
Authors: Xu Juan , Cao Jianyu , Yu Xuebin , Zou Zhiqing , Akins Daniel L. , Yang Hui 
Published: March 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.