bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Helical Zinc Complexes with Schiff Base Derivatives of β‐Diketonates or β‐Keto Esters and Ethylenediamine
Authors: Kotova Oxana , Semenov Sergey , Eliseeva Svetlana , Troyanov Sergey , Lyssenko Konstantin , Kuzmina Natalia 
Published: July 2009

AbstractThe tetradentate Schiff bases H2L = H2AC [N,N′‐ethylene‐bis(4‐iminopentan‐2‐one)], H2MAL1 [N,N′‐ethylene‐bis(methyl‐3‐iminobutanoate)], and H2MAL2 [N,N′‐ethylene‐bis(tert‐butyl‐3‐iminobutanoate)] were found to possess sufficient flexibility and were tailored to self assemble with zinc ions to form neutral bimetallic helicates with the overall composition Zn2L2. In solution for all ligands, an equilibrium between the tautomeric forms exists, which was confirmed by IR and NMR spectroscopy. X‐ray single‐crystal analysis performed for H2MAL1 (1) and H2MAL2 (2) reveals that they have similar geometrical parameters and crystallize in a trans conformation. In the crystal structures of the zinc complexes [Zn2(AC)2]·C6H6 (3), [Zn2(MAL1)2]·0.5C7H8 (4), and [Zn2(MAL2)2]·C7H8 (5), the Schiff base ligands are helically wrapped around the two four‐coordinate metal ions, which leads to an idealized D2 symmetry. The coordination polyhedron around the Zn ions in 3–5 can be described as a tetrahedral geometry comprising two O‐ and two N‐donor atoms of the Schiff base ligands. The intramolecular separation Zn···Zn varies from 3.465 to 3.628 Å. The total length of the helix is 5.85, 5.84, and 6.01 Å for structures 3, 4, and 5, respectively, while the helical pitch values are in the range 7.8–9.2 Å. Both the ligands H2L and the zinc helicates are thermally stable up to ≈150–160 °C, as shown by thermogravimetric analysis under a nitrogen atmosphere. The formation of the zinc complexes in solution is confirmed by spectrophotometric titrations, along with ESI‐MS, and has almost no effect on the absorption spectra of H2L. The Schiff bases and the Zn2L2 complexes display broad‐band, blue emission in the range 350–600 nm under a 337‐nm excitation at 77 K. Finally, the impact of electronic effects of the Schiff base substituents on the structure of the Zn complexes, especially on bond lengths within the chelate rings, and the absorption and photoluminescence spectra, are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Gas chromatographic behavior of fatty acid derivatives for mass spectrometry on low‐polarity capillary columns
Authors: Dubois Nolwenn , Barnathan Gilles , Gouygou Jean‐Paul , Bergé Jean‐Pascal 
Published: July 2009

AbstractThe gas chromatographic properties of four derivatives of fatty acids (FA), namely fatty acid methyl esters, picolinyl esters, N‐acyl pyrrolidides and 4,4‐dimethyloxazoline derivatives, which contain various structural features (double bonds, branching, hydroxyl group) in their acyl chains have been compared on a low‐polarity capillary column with a mass spectrometer as detector. Temperature programming rates yielding the highest resolution were optimized for each derivative by means of computer‐assisted column temperature optimization software. Indeed, the Drylab software represents a valuable assistance for estimating the optimum analysis conditions. Time and efforts required for such method development can greatly be reduced. Different parameters (derivatization procedure, total run time, resolution and response factor) are discussed. N‐Acyl pyrrolidides and picolinyl esters appear quite powerful for structure elucidation of polyunsaturated FA by GC‐MS, and both these types of FA derivatives can be very well separated on a low‐polarity phase.
Consecutive reactions in an oleic acid and acetic anhydride reaction medium
Authors: Peydecastaing Jerome , Vaca‐Garcia Carlos , Borredon Elisabeth 
Published: July 2009

AbstractWhen mixing acetic anhydride and oleic acid, two consecutive reactions take place. The first one yields acetic‐oleic anhydride (AOA) and acetic acid. In the second one, oleic acid reacts with AOA to form oleic anhydride at 5% in a mixture when the initial molar ratio is 1:1. Therefore, at equilibrium, the global reaction yields a mixture of AOA, acetic anhydride, oleic acid, acetic acid and oleic anhydride. Based on a new HPLC protocol, all the species of the reaction medium could be separated and quantified. This permitted for the first time to study the kinetics and thermodynamics of the reaction. In the 30–70 °C range, reactions were of order 2 with partial orders of 1 for each reactant. Equilibrium constants were determined for both reactions. Enthalpy, entropy and activation energies were calculated for the main reaction. The influence of molar ratio on the composition at equilibrium was also investigated. The synthesis of AOA could thus be understood and new data were obtained for this singular molecule scarcely cited in the CAS database.
Chemical composition of Pinus sibirica nut oils
Authors: Zadernowski Ryszard , Naczk Marian , Czaplicki Sylwester 
Published: July 2009

AbstractThe chemical composition of oil obtained from Pinus sibirica was investigated. The nonpolar lipids were the predominant lipid fraction while the triacylglycerols were the major component of this fraction. α‐ and γ‐tocopherols were the dominant tocopherols in pine oils. Eleven fatty acids (FA) were identified in pine nut oil. The unsaturated FA comprised over 90% of the total FA. Of these, polyunsaturated FA accounted for 66% of the total FA. 18:2 and 18:3 acids were the dominant unsaturated FA, while palmitic and stearic acids were the major saturated FA. Three unusual FA, namely 10,13‐octadecadienoic, gorlic and 11,13‐eicosadienoic acid, were tentatively identified in pine nut oil.
Effect of biodiesel blends on North American heavy‐duty diesel engine emissions
Authors: Yanowitz Janet , McCormick Robert L. 
Published: July 2009

AbstractWe conducted an assessment of North American heavy‐duty engine emission test results for biodiesel from 49 experimental studies, including both engine dynamometer and vehicle test results. Comparison with a commercial database showed that the engines in the emissions database are not representative of the existing North American in‐use fleet as of 2007; more than 50% of the tested engines were of 1995 or earlier vintage. Nevertheless, the results show that the use of a common biodiesel blend (B20) consistently reduces emissions of particulate matter, hydrocarbons, and carbon monoxide by 10–20%. Tests with B20 show varying effects on oxides of nitrogen (NOx). If results for pre‐1992 two‐cycle 6V‐92TA(E) engines (which represent 0.2% of the 2007 in‐use fleet but 28% of the engines tested) are removed, then there is no statistical evidence that the average NOx emissions from B0 and B20 are different (p value of 0.50 for an estimated average increase of 1%). Several researchers have used changes in engine calibration to eliminate any NOx penalty associated with B20 (in engines that show an increase in NOx with B20), while still maintaining the advantages of B20 in reducing other pollutants. The emissions effect of B20 on heavy‐duty diesel truck emissions did not show any correlation with model year or type of fuel injection equipment.
Extraction, transesterification and process control in biodiesel production from Jatropha curcas
Authors: Nazir Novizar , Ramli Nazaruddin , Mangunwidjaja Djumali , Hambali Erliza , Setyaningsih Dwi , Yuliani Sri , Yarmo Mohd. Ambar , Salimon Jumat 
Published: July 2009

AbstractBiodiesel has gained worldwide popularity as an alternative energy source due to its renewable, non‐toxic, biodegradable and non‐flammable properties. It also has low emission profiles and is environmentally beneficial. Biodiesel can be used either in pure form or blended with conventional petrodiesel in automobiles without any major engine modifications. Various non‐edible and edible oils can be used for the preparation of biodiesel. With no competition with food uses, the use of non‐edible oils as alternative source for engine fuel will be important. Among the non‐edible oils, such as Pongamia, Argemone and Castor, Jatropha curcas has tremendous potential for biodiesel production. J. curcas, growing mainly in tropical and sub‐tropical climates across the developing world, is a multipurpose species with many attributes and considerable potentials. In this article, we review the oil extraction and characterization, the role of different catalysts on transesterification, the current state‐of‐the‐art in biodiesel production, the process control and future potential improvement of biodiesel production from J. curcas.
Extraction, purification and characterization of wax from flax (Linum usitatissimum) straw
Authors: Athukorala Yasantha , Mazza Giuseppe , Oomah B. Dave 
Published: July 2009

AbstractThe chemical composition and selected physical parameters of wax extracted from flax straw with supercritical CO2 (SC‐CO2) and hexane have been determined. From the GC/MS results, clear variations in composition and component distributions were observed between SC‐CO2‐ and hexane‐extracted samples. The major components of the SC‐CO2 and hexane extracts from three flax cultivars were: fatty acids (36–49%), fatty alcohols (20–26%), aldehydes (10–14%), wax esters (5–12%), sterols (7–9%) and alkanes (4–5%). Purification of SC‐CO2‐extracted wax with silica gel chromatography yielded 0.4–0.5% (dry matter) and was composed primarily of wax esters (C44, C46 and C48) and alkanes (C27, C29 and C31). UV‐Vis scans of the purified wax samples exhibited two main peaks indicating the presence of conjugated dienes and carotenoids or related compounds. Fourier transform infrared results showed prominent peaks at 2918 (‐C‐H), 2849 (‐C‐H), 1745 (‐C=O), 1462 (‐C‐H), 1169 (‐C‐O) and 719 cm–1 (‐(CH2)n‐), with NorLin wax showing a slightly deviating pattern compared to the other samples. Thermal analysis by differential scanning calorimetry revealed a mean melting point of 55–56 °C and oxidation temperatures of 146–153 °C for purified wax from flax straw processed using different procedures.
Oxidation products of free polyunsaturated fatty acids in wheat varieties
Authors: Levandi Tuuli , Püssa Tõnu , Vaher Merike , Toomik Peeter , Kaljurand Mihkel 
Published: July 2009

AbstractOxygenated fatty acids (oxylipins) are secondary metabolites of polyunsaturated fatty acids (PUFA). Here, we present a novel high‐performance liquid chromatograpic separation on a reversed‐phase column (RP‐HPLC) coupled with electrospray ionization‐tandem mass spectrometry (ESI‐MS/MS) for the determination of various (per)oxidation products of linoleic (cis,cis‐9,12‐octadecadienoic) acid in eight different varieties (four spring and four winter varieties) of wheat (Triticum aestivum). The procedure includes extraction of oxylipins, chromatograpic separation using a linear gradient of aqueous formic acid and acetonitrile, with subsequent identification of compounds by MS/MS. Among the identified oxylipins, leukotoxin (LTX)‐diol and its isomer (iso‐LTX‐diol) are known as potentially toxic substances. The obtained data was used further for comparison of different wheat varieties by principal component analysis (PCA). From the results of PCA, differences can be observed in the patterns of wheat varieties.
Preparation of diacylglycerol‐enriched palm olein by phospholipase A1‐catalyzed partial hydrolysis
Authors: Wang Yong , Zhao Mouming , Ou Shiyi , Song Keke , Han Xue 
Published: July 2009

AbstractPartial hydrolysis of palm olein catalyzed by phospholipase A1 (Lecitase Ultra) in a solvent‐free system was carried out to produce diacylglycerol (DAG)‐enriched palm olein (DEPO). Four reaction parameters, namely, reaction time (2–10 h), water content (20–60 wt‐% of the oil mass), enzyme load (10–50 U/g of the oil mass), and reaction temperature (30–60 °C), were investigated. The optimal conditions for partial hydrolysis of palm olein catalyzed by Lecitase Ultra were obtained by an orthogonal experiment as follows: 45 °C reaction temperature, 44 wt‐% water content, 8 h reaction time, and an enzyme load of 34 U/g. The upper oil layer of the reaction mixture with an acid value of 54.26 ± 0.86 mg KOH/g was first molecularly distilled at 150 °C to yield a DEPO with 35.51 wt‐% of DAG. The DEPO was distilled again at 250 °C to obtain a DAG oil with 74.52 wt‐% of DAG. The composition of the acylglycerols of palm olein and the DEPO were analyzed and identified by high‐performance liquid chromatography (HPLC) and HPLC/electrospray ionization/mass spectrometry. The released fatty acids from the partial hydrolysis of palm olein catalyzed by phospholipase A1 showed a higher saturated fatty acid content than that of the raw material.
Molecular Tailored Histidine‐Based Complexing Surfactants: From Micelles to Hydrogels
Authors: Gizzi Patrick , Pasc Andreea , Dupuy Nicolas , Parant Stéphane , Henry Bernard , Gérardin Christine 
Published: July 2009

AbstractNovel histidine‐based complexing surfactants, designed as AA‐His‐EOm‐Cn, containing trifunctional moduli (peptidic/hydrophilic/hydrophobic) were synthesized by a modular step‐by‐step procedure, which allowed easy structural changes, and consequently correlations between their molecular structures and their self‐assembling properties could be established. Thus, micelles or hydrogels could be obtained by simply modifying the hydrophobic tail lengths or the junction between the different moduli of the designed compounds. At low pH values, all compounds were surface active in aqueous solutions. At higher pH values, in the range 8–10, micellization took place for decyl compounds (n = 10), whereas hydrogelation occurred for longer chain lengths (n = 12, 14), and this, at very‐low concentrations of surfactant (<0.3 wt.‐%), could thus act as low molecular weight gelator (LMWG). The driving forces for gel formation were noncovalent intermolecular interactions such as π‐stacking and hydrophobic and hydrogen‐bonding interactions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of Unusually Substituted Ureas Starting from Bis(1,3,4‐thiadiazolo)‐1,3,5‐triazinium Halides via Oxo‐imidothioate Zwitterions
Authors: Schulz Martin , Michnacs Marion , Görls Helmar , Anders Ernst 
Published: July 2009

AbstractBis(1,3,4‐thiadiazolo)‐1,3,5‐triazinium halides 1 can be converted into various products such as guanidines or bis(azolyl)alkanes. However, they also react with hydroxide ions in aqueous solution to form novel heterocyclic‐substituted ureas 2a–i. The yields were increased from moderate to good or excellent in the presence of excess guanidine 3. The assumption that hydrogen‐bonded intermediate encounter complexes EC are formed gives a reasonable explanation for the observed reaction path. The molecular structures of some of the crystalline products 2 were determined by X‐ray analysis. Furthermore, with copper(II) a dinuclear complex 8 is formed with the two metal ions in a distorted octahedral environment; a water molecule acts as a bridging ligand between the CuII ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Efficient Regiospecific Conjugated Ring Fusion in N‐Confused Porphyrin
Authors: Chmielewski Piotr J. , Maciołek Justyna , Szterenberg Ludmiła 
Published: July 2009

AbstractAcid‐catalyzed exocyclic ring formation in meso‐tetrakis(3′,5′‐dimethoxyphenyl)‐2‐aza‐21‐carbaporphyrin takes place regioselectively between the external carbon atom of the confused pyrrole and the ortho‐carbon atom of the adjacent meso‐aryl group. The ring fusion strongly alters the spectroscopic properties of the macrocycle, but its aromaticity is preserved, as shown by NMR spectroscopy as well as DFT calculations. A tendency to self‐associate is observed for partially protonated and nickel(II)‐metalated systems. A novel silver(I)‐bridged dimer is formed in the reaction of the fused carbaporphyrin with AgBF4. Cyclic voltammetry studies of this system indicate an interaction between the subunits. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Syntheses and15N NMR Spectra of Iminodiaziridines – Ring‐Expansions of 1‐Aryl‐3‐iminodiaziridines to 1H‐ and 3aH‐Benzimidazoles, 2H‐Indazoles, and 5H‐Dibenzo[d,f][1,3]diazepines
Authors: Quast Helmut , Ross Karl‐Heinz , Philipp Gottfried , Hagedorn Manfred , Hahn Harald , Banert Klaus 
Published: July 2009

AbstractIminodiaziridines are synthesized by (i) 1,3‐dehydrochlorination with potassiumtert‐butoxide ofN‐chloroguanidines, generated in situ fromN,N′,N″‐substituted guanidines withtert‐butyl hypochlorite, and (ii) base‐mediated 1,3‐elimination of sulfuric acid fromN,N′,N″‐substituted hydroxyguanidineO‐sulfonic acids. At elevated temperatures, (alkylimino)diaziridines undergo valence isomerization by 1,3‐shift, [2+1] cycloelimination to afford isocyanides and diazenes, and ring‐opening elimination to yield alkylideneguanidines.N′‐Aryl‐N‐hydroxyguanidineO‐sulfonic acids furnish (N‐arylimino)diaziridines, but no 1‐aryl‐3‐iminodiaziridines, instead giving rearranged isomers. Precursors containing perdeuteratedtert‐butyl groups give rearranged products that show complete scrambling. This indicates that 1‐aryl‐3‐iminodiaziridines are intermediates that undergo very rapid degenerate valence isomerization. Provided that theortho‐aryl positions are substituted, high yields of (arylimino)diaziridines are obtained, along with 2‐imino‐2,3‐dihydro‐3aH‐benzimidazoles. Otherwise, 2‐amino‐1H‐benzimidazoles and strongly fluorescent 3‐amino‐2H‐indazoles, originating from rearrangements of the elusive 1‐aryl‐3‐iminodiaziridines, predominate.N′,N″‐Diaryl‐N‐hydroxyguanidineO‐sulfonic acids give only rearranged products: a 2‐amino‐1H‐benzimidazole and a 6‐amino‐5H‐dibenzo[d,f][1.3]diazepine if aryl = phenyl, or a 2‐imino‐2,3‐dihydro‐3aH‐benzimidazole if aryl = mesityl. 3aH‐Benzimidazoles slowly dimerize through Diels–Alder reactions.15N NMR signals were assigned to thesynandantiring nitrogen atoms of iminodiaziridines with the help of a combination of homonuclear NOE and HN‐HMBC or HN‐gHMBC experiments. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Towards Long‐Living Metathesis Catalysts by Tuning the N‐Heterocyclic Carbene (NHC) Ligand on Trifluoroacetamide‐Activated Boomerang Ru Complexes
Authors: Clavier Hervé , Caijo Fréderic , Borré Etienne , Rix Diane , Boeda Fabien , Nolan Steven P. , Mauduit Marc 
Published: July 2009

AbstractThe synthesis and characterization of three novel trifluoromethylamido‐containing “boomerang” precatalysts bearing various N‐heterocyclic carbene (NHC) ligands are reported. Comparative kinetic and stability studies show the significant effect of the NHC on the catalyst reaction profile. An investigation of the reaction scope for diverse metathesis transformations has allowed us to establish the influence of the NHC on catalyst activity, especially as a function of substrate steric bulk. The excellent stability of one of the novel precatalysts is disclosed, and allowed for its recovery at the end of catalytic reactions. Large‐scale ring‐closing metathesis, enyne‐metathesis and cross‐metathesis experiments have revealed the recoverability of the catalyst. ICP‐MS analyses of the synthesized products reveal Ru contamination levels of less than 2.5 ppm.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Facile Access to Fluorinated Aryl and Vinyl Ethers through Copper‐Catalysed Reaction of Fluoro Alcohols (Eur. J. Org. Chem. 21/2009)
Authors: Vuluga Daniela , Legros Julien , Crousse Benoit , Bonnet‐Delpon Danièle 
Published: July 2009

AbstractThe cover picture shows the reaction between fluoro alcohols and aryl halides in the presence of copper iodide to afford fluoro ethers. The incorporation of the trifluoroethoxy moiety generally brings lipophilicity and metabolic stability to the substrate, and this group is found in numerous pharmaceuticals such as Flecainide. Details are discussed in the article by J. Legros, B. Crousse et al. on p. 3513 ff. The Région Ile‐de‐France is kindly acknowledged for support.
Women's reactions to ingroup members who protest discriminatory treatment: The importance of beliefs about inequality and response appropriateness
Authors: Garcia Donna M. , Schmitt Michael T. , Branscombe Nyla R. , Ellemers Naomi 
Published: July 2009

AbstractOur goal was to identify factors that shape women's responses to ingroup members who protest gender discrimination. We predicted and found that women who perceived gender discrimination as pervasive regarded a protest response as being more appropriate than a no protest response and expressed greater liking and less anger towards a female lawyer who protested rather than did not protest an unfair promotion decision. Further, beliefs about the appropriateness of the response to discrimination contributed to evaluations of the protesting lawyer. Perceptions that the complaint was an appropriate response to the promotion decision led to more positive evaluations of an ingroup discrimination protester. Copyright © 2009 John Wiley & Sons, Ltd.
Reopening the study of extreme social behaviors: Obedience to authority within an immersive video environment
Authors: Dambrun Michaël , Vatiné Elise 
Published: July 2009

AbstractIn this study, we used a paradigm similar to the one used by Milgram in his classic obedience study, using an immersive video environment. We manipulated the victim's degree of visibility and his ethnicity. When the victim was hidden, the level of obedience we obtained was similar to Milgram's. Replicating previous findings observed in real environments, participants were more obedient when the victim was hidden than when he was visible, and the more obedient participants negated their own responsibility by projecting responsibility on both the victim and the experimenter. State‐anger and right‐wing authoritarianism (RWA) emerged as two significant predictors of the level of obedience. Illustrating an underlying process of racial‐dehumanization, participants reported less anxiety and distress when the victim was a North African than when the victim was of the same racial origin as the participant. These results underscore the usefulness of using immersive environments when studying extreme social behaviors. Copyright © 2009 John Wiley & Sons, Ltd.
A group just like me: The moderating role of conservation values on social projection
Authors: Amit Adi , Roccas Sonia , Meidan Michal 
Published: July 2009

AbstractWe examined the moderating role of personal values on social projection. Study 1 was conducted prior to the 1999 Israeli elections among activists of the Center party, a newly established centrist party. The more importance activists attributed to conservation values (values that emphasize stability and certainty) the more they projected their political views to their party. Study 2 was conducted prior to the 2003 Israeli elections among students with varied attitudes toward the Kadima party, another newly established centrist party. Conservation values interacted with support for the Kadima party in their effect on social projection: The more importance participants attributed to conservation values, the more positive was the relationship between support for the party and social projection. In Study 3, we examined the role of conservation values in an experimental study in which participants were members of a virtual team: Raising the accessibility of conservation values resulted in higher levels of social projection. Taken together, findings indicate that emphasizing conservation values leads to greater social projection. Copyright © 2009 John Wiley & Sons, Ltd.