bluuebunny/crossref_metadata_2025 huggingface dataset:
Strategien zur Modulation von Protein‐Protein‐Wechselwirkungen mit synthetischen Substanzen
Authors: Yin Hang , Hamilton Andrew D.
Published: June 2005

Die Entwicklung niedermolekularer Modulatoren von Protein‐Protein‐Wechselwirkungen gilt als wichtiges Forschungsziel mit großem Potenzial für die Entdeckung neuer Therapeutika. Trotz anspruchsvoller Voraussetzungen gibt es eine Reihe von Beispielen für die Inhibierung der Wechselwirkung großer Proteinbindungspartner durch einen niedermolekularen Liganden. In diesem Aufsatz geben wir einen Überblick über die Strategien zur Modulierung von Protein‐Protein‐Wechselwirkungen und präsentieren den aktuellen Forschungsstand beim rationalen Design von Mimetika, die die Strukturen und Funktionen ihrer natürlichen Zielstrukturen abbilden.
Strategies for Targeting Protein–Protein Interactions With Synthetic Agents
Authors: Yin Hang , Hamilton Andrew D.
Published: June 2005

The development of small‐molecule modulators of protein–protein interactions is a formidable goal, albeit one that possesses significant potential for the discovery of novel therapeutics. Despite the daunting challenges, a variety of examples exists for the inhibition of two large protein partners with low‐molecular‐weight ligands. This review discusses the strategies for targeting protein–protein interactions and the state of the art in the rational design of molecules that mimic the structures and functions of their natural targets.
Morphological Characterization of Point Patterns
Authors: Mecke K. R. , Stoyan D.
Published: June 2005

A triplet of function s for the statistical characterization of planar point patterns is introduced. They are related to the integral‐geometric quantities area, boundary length and Euler number of patterns of discs centred at the given points. These functions are able to give information on the distribution of a given point pattern which the traditional summary statistics of point process theory do not offer and so can lead to an improved statistical description.

The paper describes the statistical estimation of the new characteristics. Some examples illustrate their application in the exploratory analysis of point patterns of tree positions in forests, in comparison to results obtained by means of second‐order and distance characteristics. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solution properties of (1→3)‐α‐D‐glucan and its sulfated derivative from Poria cocos mycelia via fermentation tank
Authors: Huang Qilin , Zhang Lina
Published: June 2005

From Poria cocos mycelia yielded via a pilot scale facility–fermentation tank, a water‐insoluble (1→3)‐α‐D‐glucan coded as Pi‐PCM3‐I was isolated by extraction with 0.5 M NaOH/0.01 M NaBH4 aqueous solution. Nine fractions from F1 to F9 with a weight‐average molecular mass (Mw) range from 7.75 × 104 to 57.3 × 104 were prepared from the Pi‐PCM3‐I sample by a nonsolvent addition method. The fractions were reacted with chlorosulfonic acid–pyridine complex to product water‐soluble sulfated derivatives coded as S1 to S8 with Mw from 2.36 × 104 to 14.5 × 104 and degree of substitution (DS) of 0.86–1.38. Mw, z‐average radius of gyration (〈s2〉 ), the second virial coefficient (A2), and the intrinsic viscosity ([η]) of the native and sulfated Pi‐PCM3‐I were measured by laser light scattering (LLS), size‐exclusion chromatography combined with LLS (SEC–LLS), and viscometry at 25°C. The Mark–Houwink equations for Pi‐PCM3‐I in 0.25 M LiCl/dimethylsulfoxide (DMSO) (Me2SO) and for its sulfated derivative in 0.15 M NaCl aqueous solution at 25°C were established to be [η] = 1.33 × 10−2 M (mL g–1) and [η] = 1.46 × 10−4 M (mL g–1), respectively. On the basis of theories for a wormlike cylinder model, the conformational parameters of the native and sulfated Pi‐PCM3‐I were calculated to be 760 ± 50 and 1060 ± 30 nm–1 for the molar mass per unit contour length (ML), 6.3 ± 0.5 and 13.1 ± 1 nm for the persistence length (q), and 14.9 ± 0.2 and 31.8 ± 1 for the characteristic ratio (C∝), respectively. The results revealed that Pi‐PCM3‐I existed as an extended flexible chain in 0.25 M LiCl/Me2SO, and its sulfated derivative existed as a semistiff chain in 0.15 M NaCl aqueous solution. Furthermore, Pi‐PCM3‐I possessed similar structure and molecular parameters to wc‐PCM3‐I from a rotary shaker; this suggests promising industrialization of Poria cocos polysaccharides. © 2005 Wiley Periodicals, Inc. Biopolymers 79: 28–38, 2005

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Critical thinking revisited: Its past, present, and future
Authors: Barnes Cynthia A.
Published: June 2005

More than a decade ago, community colleges across the nation mobilized legions of faculty to craft critical thinking initiatives on their campus. Were these initiatives simply the latest educational fad, or did the implementation provoke substantive, lasting changes not only in what we teach but in how we teach?
The state of critical thinking today
Authors: Paul Richard
Published: June 2005

Research demonstrates that most college faculty lack a substantive concept of critical thinking, though they mistakenly think otherwise. This chapter spells out the implications of such a robust concept and emphasizes that success in bringing a substantive concept of critical thinking to college faculty requires well‐planned, long‐term professional development based explicitly on the multiple dimensions of a substantive concept of critical thinking.
Critical thinking as the key to the Learning College: A professional development model
Authors: Elder Linda
Published: June 2005

Critical thinking is foundational to the effective teaching of any subject, and it must be at the heart of any professional development program. This chapter presents a long‐term professional development model based on a substantive concept of critical thinking, and ties critical thinking to the concept of the Learning College.
Overcoming impostorship, cultural suicide, and lost innocence: Implications for teaching critical thinking in the community college
Authors: Brookfield Stephen D.
Published: June 2005

Teaching critical thinking in community college classrooms involves helping students overcome emotional barriers and question and critique commonly held assumptions.
Problems with two standard models for teaching critical thinking
Authors: Nosich Gerald M.
Published: June 2005

Two common models of teaching critical thinking in a discipline fail to do justice to the essential role critical thinking plays in all learning or to its role in the discipline as a whole. This chapter describes a model that emphasizes a more central role for critical thinking in shaping all course activity and in focusing on the most fundamental and powerful discipline‐based concepts.
Thwarting expectations: Assignments from a critical thinking class
Authors: Herman Jerry
Published: June 2005

Challenged by unconventional assignments, students examine untested assumptions and in the process become better critical thinkers.
Dramatic Change in the Tertiary Structure of Giant DNA without Distortion of the Secondary Structure Caused by Pteridine–Polyamine Conjugates
Authors: Chen Ning , Murata Shizuaki , Yoshikawa Kenichi
Published: June 2005

Pteridine–polyamine conjugates, such as 2‐polyamine (1,3‐diaminopropane and spermine) substituted 6,7‐dimethyl‐3H‐pteridine‐4‐one, induce a folding transition of a giant DNA molecule more effectively than the corresponding polyamines. However, since neither a DNA high‐temperature shift of denaturation (Tm) curve nor distortion of the UV/fluorescence spectra is observed in a mixture of these compounds with DNA, they do not interact with the DNA duplex strongly.
Synthesis of the C(1)–C(11) Polyene Fragment of Apoptolidin with a New Sulfur Dioxide‐Based Organic Chemistry
Authors: Bouchez Laure C. , Vogel Pierre
Published: June 2005

A new sulfur dioxide‐based organic chemistry has been developed as a novel approach for the stereoselective synthesis of polyene fragments based on our one‐pot, four‐component synthesis of polyfunctional ε‐alkanesulfonyl‐γ,δ‐unsaturated ketones. The flexibility and efficiency of this methodology are illustrated by the preparation of (+)‐methyl (2E,4E,6E,8R,9S)‐9‐{[(tert‐butyl)dimethylsilyl]oxy}‐2,4,6,8‐tetramethyl‐11‐(triethylsilyl)undeca‐2,4,6‐trien‐10‐ynoate, a synthetic intermediate of Nicolaou and co‐workers, that corresponds to the C(1)–C(11) fragment of apoptolidin, which was used by the authors in their total synthesis of this promising anticancer agent.
2,5‐Dioxido‐1,4‐benzoquinonediimine (H2L2−), A Hydrogen‐Bonding Noninnocent Bridging Ligand Related to Aminated Topaquinone: Different Oxidation State Distributions in Complexes [{(bpy)2Ru}2(μ‐H2L)]n (n=0,+,2+,3+,4+) and [{(acac)2Ru}2(μ‐H2L)]m (m=2−,−,0,+,2+)
Authors: Kar Sanjib , Sarkar Biprajit , Ghumaan Sandeep , Janardanan Deepa , van Slageren Joris , Fiedler Jan , Puranik Vedavati G. , Sunoj Raghavan B. , Kaim Wolfgang , Lahiri Goutam Kumar
Published: June 2005

The symmetrically dinuclear title compounds were isolated as diamagnetic [(bpy)2Ru(μ‐H2L)Ru(bpy)2](ClO4)2 (1‐(ClO4)2) and as paramagnetic [(acac)2Ru(μ‐H2L)Ru(acac)2] (2) complexes (bpy=2,2′‐bipyridine; acac−=acetylacetonate=2,4‐pentanedionato; H2L=2,5‐dioxido‐1,4‐benzoquinonediimine). The crystal structure of 2⋅2 H2O reveals an intricate hydrogen‐bonding network: Two symmetry‐related molecules 2 are closely connected through two NH(H2L2−)⋅⋅⋅O(acac−) interactions, while the oxygen atoms of H2L2− of two such pairs are bridged by an (H2O)8 cluster at half‐occupancy. The cluster consists of cyclic (H2O)6 arrangements with the remaining two exo‐H2O molecules connecting two opposite sides of the cyclo‐(H2O)6 cluster, and oxido oxygen atoms forming hydrogen bonds with the molecules of 2. Weak antiferromagnetic coupling of the two ruthenium(III) centers in 2 was established by using SQUID magnetometry and EPR spectroscopy. Geometry optimization by means of DFT calculations was carried out for 12+ and 2 in their singlet and triplet ground states, respectively. The nature of low‐energy electronic transitions was explored by using time‐dependent DFT methods. Five redox states were reversibly accessible for each of the complexes; all odd‐electron intermediates exhibit comproportionation constants Kc>108. UV‐visible‐NIR spectroelectrochemistry and EPR spectroscopy of the electrogenerated paramagnetic intermediates were used to ascertain the oxidation‐state distribution. In general, the complexes 1n+ prefer the ruthenium(II) configuration with electron transfer occurring largely at the bridging ligand (μ‐H2Ln−), as evident from radical‐type EPR spectra for 13+ and 1+. Higher metal oxidation states (iii, iv) appear to be favored by the complexes 2m; intense long‐wavelength absorption bands and RuIII‐type EPR signals suggest mixed‐valent dimetal configurations of the paramagnetic intermediates 2+ and 2−.
Gas Phase Epoxidation of Propylene with O2 Induced by Alternating Electric Field
Authors: Ming‐Xing Guo , Hong‐Chen Guo , Xiang‐Sheng Wang , Wei‐Min Gong
Published: June 2005

In non‐catalytic direct conversion of propylene with oxygen to propylene oxide by using dielectric barrier discharge under conditions of room temperature and atmospheric pressure, the selectivity to propylene oxide from propylene was >30% at propylene conversion ranging from 3.91% to 81.72%.
Synthesis and Characteristics of LiNi0.85Co0.15O2 Cathode Materials by Particulate Sol‐Gel Method for Lithium Ion Batteries
Authors: Xian‐Jun Zhu , Hong‐Hao Chen , Hui Zhan , Han‐Xing Liu , Dai‐Ling Yang , Yun‐Hong Zhou
Published: June 2005

A particulate sol‐gel (PSG) method has been successfully used to prepare LiNi0.85Co0.15O2 cathode materials, utilizing the reaction of LiOH·H2O with Ni(CH3COO)2·4H2O and Co(CH3COO)2·4H2O in water‐ethanol system. The thermal history of the as‐prepared xerogel was established by differential thermal analysis and thermogravimetric analysis. Powder X‐ray diffraction confirmed the formation of layered α‐NaFeO2 structure at temperature of 700 °C under flowing oxygen. Scanning electron microscope exhibited that the crystalline powder prepared by PSG method had relatively smaller particle size with narrow distribution than the one prepared by solid state reaction. The first discharge capacity of the material by PSG method was 196.4 mAh/g, and the 10th discharge capacity was 189.1 mAh/g at the current density of 18 mA/g between 3.0 and 4.3 V. Its cycling reversibility was observed to be much better than that by solid state reaction, which had 187.3 mAh/g of the first discharge capacity and 167.1 mAh/g of the 10th discharge capacity.
A Theoretical Study on the Mechanism of the Cycloaddition Reaction between Alkylidenestannylene and Ethylene
Authors: Xiu‐Hui Lu , Hai‐Bin Yu , Wei‐Rong Wu
Published: June 2005

The mechanism of a cycloaddition reaction between singlet alkylidenestannylene and ethylene has been investigated with MP2/3‐21G* and B3LYP/3‐21G* methods, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. Energies for the involved conformations were calculated by CCSD(T)//MP2/3‐21G* and CCSD(T)//B3LYP/3‐21G* methods, respectively. The results show that the dominant reaction pathway of the cycloaddition is that an intermediate (INT) is firstly formed between the two reactants through a barrier‐free exothermic reaction of 39.7 kJ/mol, and the intermediate then isomerizes to a four‐membered ring product (P2.1) via a transition state TS2.1 with a barrier of 66.8 kJ/mol.
Synthesis, Characterization and Electrochemical Behavior of Hepta‐O‐acetyl‐β‐lactosyl Isothiocyanate
Authors: Shu‐Sheng Zhang , Bo Yang , Ji‐Zhi Li , Xue‐Mei Li , Gui‐Fen Jie , Kui Jiao
Published: June 2005

A new compound of hepta‐O‐acetyl‐β‐lactosyl isothiocyanate has been synthesized and its structure was determined by X‐ray crystallography. The compound crystallizes in the orthorhombic system, with space group P212121 and cell dimensions of a=1.23282(7) nm, b=1.80012(10) nm, b=1.85230(10) nm, α=β=γ=90°, V=4.1107(4) nm3, and Z=4. The electrochemical experimental results indicate that both dsDNA and ssDNA had obvious reduction effect on the peak current of the title compound, which was bound to DNA mainly through electrostatic binding.
Heat Capacity and Enthalpy of Fusion of Fenoxycarb
Authors: Xiao‐Hong Sun , Yuan‐Fa Liu , Zhi‐Cheng Tan , Ying‐Qi Jia , Jian‐Wu Yang , Mei‐Han Wang
Published: June 2005

Fenoxycarb was synthesized and its heat capacities were precisely measured with an automated adiabatic calorimeter over the temperature range from 79 to 360 K. The sample was observed to melt at (326.31±0.14) K. The molar enthalpy and entropy of fusion as well as the chemical purity of the compound were determined to be (26.98±0.04) kJ·mol‐1, (82.69±0.09) J·K‐1·mol‐1 and 99.53%±0.01%, respectively. The thermodynamic functions relative to the reference temperature (298.15 K) were calculated based on the heat capacity measurements in the temperature range between 80 and 360 K. The extrapolated melting temperature for the absolutely pure compound obtained from fractional melting experiments was (326.62±0.06) K. Further research on the melting process of this compound was carried out by means of differential scanning calorimetry technique. The result was in agreement with that obtained from the measurements of heat capacities.
Dispersion of Metal Phthalocyanines on Surface of TiO2
Authors: Jian‐Feng Zhu , Chun‐Ming Wang , Yue‐Xiang Zhu , Bi‐Ying Zhao , You‐Chang Xie
Published: June 2005

Dispersion of copper(II) phthalocyanine (CuPc), copper(II) phthalocyaninesulfonate (CuPcS) and cobalt(II) phthalocyaninetetrasulfonate (CoPcTS) on the surface of titanium dioxide was investigated by XRD, XPS, FT‐IR and UV‐Vis techniques. Results show that interaction between CuPc and TiO2was very weak and CuPc was difficult to disperse on the surface of the support. While partly sulfurized CuPcS could be dispersed on the surface of support through sulfo‐groups and its dispersion capacity was determined to be 0.085 g CuPcS/g TiO2. Completely sulfurized CoPcTS could also be dispersed on the surface of TiO2as a monolayer and its dispersion capacity was 0.12 g CoPcTS/g TiO2. Interactions of the sulfo‐groups as well as the electrons of CoPcTS with the surface of TiO2could be evidenced by FT‐IR characterization. Therefore, it was suggested that CoPcTS molecules be adsorbed on the surface of TiO2in a flat‐lying mode while CuPcS in a slanting one. UV‐Vis spectra show that the dispersed CuPcS and CoPcTS molecules exist in both forms of monomers and dimers.
Efficient Preparation of Metal Organosols by Phase Transfer
Authors: Ji‐Kuan Zhao , Xiao Chen , Chun‐Jie Yang , Zhen‐Ming Sui , Guo‐Dong Zhang , Yong‐Cun Chai , Jie Liu
Published: June 2005

Organosols of silver and gold nanoparticles stabilized by sodium oleate were prepared with high efficiency by simple phase transfer of their hydrosols to isooctane. Concentrations of sodium oleate and magnesium chloride have crucial effects on the phase transfer efficiency. UV‐visible absorption spectroscopy and transmission electron microscopy have been used to characterize the nanoparticles. A possible phase transfer mechanism was proposed based on the anchoring positions of oleate deduced by molecular modeling calculations.
AM1 Transition State Modeling for the Enantioselectivities in the Chiral Oxazaborolidine‐Catalyzed Reductions of α‐ and β‐Aminoketones
Authors: Jian‐Fen Fan , Yun‐Xiang Lu , Qiu‐Xia Wang , Li‐Fen Wu
Published: June 2005

AM1 transition state (TS) models were developed for the enantioselectivities in the reductions of α‐ and β‐aminoketones catalyzed by (S)‐4‐benzyl‐5,5‐diphenyl‐1,3,2‐oxazaborolidine. The result showed that β‐aminoketone gave better enantioselectivity than its α‐analog. Different chiralities of the final products were obtained, R for the former and S for the latter. These semiempirical TS models are consistent with the experimental data.
Study on the Binding Mode of a Co(II) Complex with DNA
Authors: Qing‐Hua Zhou , Pin Yang
Published: June 2005

The mode of binding of CoLCl2, here L=bis(2‐benzimidazolylmethyl)amine, with calf thymus DNA has been investigated by fluorescence measurements, equilibrium dialysis, viscosity experiments and gel electrophoresis. The complex was found to bind but weakly to DNA, with binding constant of 1.96×104 L/mol determind at 20 °C in a solution containing 5 mmol/L Tris‐HCl (pH 7.1) and 50 mmol/L NaCl. Polyelectrolyte theory was applied to analyse these values. Viscosity experiments show that binding did not alter the relative viscosity of DNA with any complexes to an appreciable extent. Electrophoresis test displayed that the compound could not cleave the DNA. These results show that the complex is essentially electrostatically bound to DNA.
Synthesis, Crystal Structures and Properties of Tetrametallic Complexes: [M2(phen)4(FCA)2](ClO4)2·(H2O)2 (M=Zn or Co, phen=1,10‐phenanthroline, FCA=anion of 3‐ferrocenyl‐2‐crotonic acid)
Authors: Jia‐Xiang Yang , Zhang‐Jun Hu , Ze Zhang , Yu‐Peng Tian , Qing‐Liang Liu , Suchada Chantrapromma , Hoong‐Kun Fun
Published: June 2005

Two new complexes [Zn2(phen)4(FCA)2](ClO4)2·(H2O)2 (1) and [Co2(phen)4 (FCA)2](ClO4)2·(H2O)2 (2) (FCA=anion of 3‐ferrocenyl‐2‐crotonic acid, phen=1,10‐phenanthroline) have been synthesized, and characterized by elemental analysis, IR, UV‐Vis spectra, thermal analyses, and single‐crystal X‐ray diffraction. Two M(II) (M=Zn or Co) ions are bridged by two FCA anions with syn‐anti bridging ligands, leading to dimeric cores, [M2(phen)4(FCA)2]2+, and each M(II) ion is six‐coordinated in a distorted octahedral geometry by two chelate phen ligands and two μ2‐carboxylate oxygen atoms from two FCA groups. The M(II)…M(II) intradimer distances are 0.4391 and 0.4462 nm in 1 and 2, respectively. Electrochemical properties of the complexes have been discussed.
Experimental and Density Functional Theory Calculational Studies on 2,3‐Diaryl‐tetrazole‐5‐thione
Authors: Fang‐Fang Jian , Pu‐Su Zhao , Yu‐Xia Ou , Feng‐Li Bei
Published: June 2005

2,3‐Diaryl‐tetrazole‐5‐thione (diaryl=diphenyl, di(p‐methylphenyl) and di(p‐chlorophenyl)) has been synthesized and characterized by elemental analysis, IR and electronic absorption spectroscopy. Two of them have also been characterized by X‐ray diffraction analysis. Density functional theory calculations of the structures, charge distribution, natural bond orbital and topological analysis of the three compounds were performed at B3LYP/6‐31G* level. The calculational results are in good agreement with the X‐ray data and show that different substitute group results in different charge distribution, the exocyclic sulfur atom has the biggest negative charge value and this site is the most likely site of protonation and methylation as well as the potential coordination site with metallic ions. The predicted harmonic vibration frequencies were compared with the experimental values. On the basis of vibrational analyses, the thermodynamic properties of these compounds at different temperatures were calculated, which reveal that$ S^{0}_{\rm m} $,$ H^{0}_{\rm m} $and temperatures have good linear correlations. The calculations of second order optical nonlinearity have also been carried out and relatively high molecular hyperpolarizability values of 1.0913×10‐29‐1.6518×10‐29esu were predicted.
Thermodynamics of Solvent Extraction of Thallium(I) with Di(2‐ethylhexyl)dithiophosphoric Acid
Authors: Xing‐Zhi Liu , Da‐Wei Fang , Yan‐Hong Kang , Jun Li , Shu‐Liang Zang
Published: June 2005

In Tl2SO2+Na2SO4+di(2‐ethylhexyl)dithiophosphoric acid+n‐C8H18+water system, the Tl+ equilibrium molalities were measured at ionic strength from 0.1 to 2.0 mol·kg‐1 containing Na2SO4 as supporting electrolyte in aqueous phase and at constant molality of extractant at temperatures from 278.15 to 303.15 K in organic phase. The standard extraction constants K0 at various temperatures were obtained by methods of extrapolation and polynomial approximation. Thermodynamic quantities for the extraction process were calculated.
QCM Coated with Self‐assembled Cystine‐bearing 1,3‐Bridged Calix[4]arenes for Recognizing Gas‐phase Butylamines
Authors: Yuan‐Yuan Li , Hong‐Zong Yin , Xi‐Wen He , Lang‐Xing Chen , Guo‐Zhu Zhang , Jia‐Qi He
Published: June 2005

Two cystine‐bearing 1,3‐bridged calix[4]arenes were used as the coatings of the quartz crystal microbalance (QCM) with gold electrodes. The two calix[4]arene derivatives were self‐assembled onto the gold electrode surface by the covalent attachment between the di‐sulfur and gold. The compound of cystine‐bearing bi‐phenylalanine 1,3‐bridged calix[4]arene (CPC) with longer alkyl chain had better self‐assembled capacity onto the fresh surfaces of gold electrode than that of cystine‐bearing 1,3‐bridged calix[4]arene (CC) with comparably shorter alkyl chain. The modified QCM sensors were used to recognize the butylamine isomers in gas. The results showed that the QCM coated with both compounds had preferential affinity to n‐butylamine, then i‐butylamine, t‐butylamine in the range of low concentrations, indicating that in the recognition process, the steric hindrance effect played an important role when forming complex with guest molecules. When the concentrations of the analytes were increased, the polarity and the magnetism of the butylamine became determinative factors. The reversibility was improved greatly and the equilibrium time was much shorter on the self‐assembled film than on the film obtained by dropping coating.
A Novel and Efficient Process for Preparation of 2,4‐Diphenyl‐4‐methyl‐1‐pentene in Brönsted Acidic Ionic Liquid [Hmim]+B${\rm F}^{-}_{4} $
Authors: Peng‐Rong Zhang , Ji‐Yan Du , Fan Yang , Gang Zou , Jie Tang
Published: June 2005

Highly selective dimerization of α‐methylstyrene (AMS) was effected using a Brönsted acidic ionic liquid, [Hmim]+B${\rm F}^{-}_{4} $, as solvent as well as catalyst, providing the industrial high‐value olefin, 2,4‐diphenyl‐4‐methyl‐1‐pentene (1‐PT). The desired dimer 1‐PT could be obtained in 90% yield at 96% conversion in the dimerization of AMS under optimized conditions. Features of the procedure include use of readily available ionic liquid‐catalyst, exclusion of volatile organic solvents, higher selectivity and efficiency for 1‐PT.
Proline Catalyzed Asymmetric Aldol Reaction between Methyl Ketones and 1‐Aryl‐2,2,2‐trifluoroethanones
Authors: Li‐Hua Qiu , Zong‐Xuan Shen , Chang‐Qing Shi , Yan‐Hua Liu , Ya‐Wen Zhang
Published: June 2005

Direct asymmetric aldol addition of methyl ketones to 2,2,2‐trifluoro‐1‐phenylethanone and its ring‐substituted derivatives was achieved using L‐proline as a chiral promoter. Various optically active β‐trifluoromethyl‐β‐hydroxy ketones were obtained in almost quantitative yields with moderate enantioselectivities up to 64 % ee.
Syntheses of Benzimidazoles, Quinoxalines and 3,3‐Dihydro‐1H‐1,5‐benzodiazepines Starting from o‐Phenylenediamine
Authors: Yong Cui , Xiu‐Bo Tang , Chang‐Xing Shao , Ji‐Tai Li , Wen‐Hua Sun
Published: June 2005

A series of benzo‐fused heteroaromatic compounds with 5‐, 6‐ and 7‐membered rings, such as benzimidazole, quinoxaline and 1H‐1,5‐benzodiazepine derivatives, were synthesized through condensation reaction of o‐phenylenediamine with aryl aldehydes or ketones. The experimental conditions were carefully examined, and the products were characterized by 1H NMR, 13C NMR, MS, IR and elemental analyses. In addition, the structure of a benzodiazaepine derivative with 7‐membered ring was confirmed by single crystal X‐ray diffraction analysis.
One‐pot Synthesis of Bis(dihydropyrimidinone‐4‐yl)benzene Using Boric Acid as a Catalyst
Authors: Shu‐Jiang Tu , Xiao‐Tong Zhu , Fang Fang , Xiao‐Jing Zhang , Song‐Lei Zhu , Tuan‐Jie Li , Da‐Qing Shi , Xiang‐Shan Wang , Shun‐Jun Ji
Published: June 2005

A simple effective synthesis of bis(dihydropyrimidinone‐4‐yl)benzene derivatives, using boric acid as catalyst, from isophthalic aldehyde or terephthalic aldehyde, 1,3‐dicarbonyl compounds and urea or thiourea in glacial acetic acid was described. As the expansion of the classical Biginelli reaction, this method has the advantage of excellent yields 83%–94% and short reaction time 0.5–1.5 h.
VSMP for Modeling the Biodegradability of Substituted Benzenes Based on Electrotopological State Indices for Atom Types
Authors: Shu‐Shen Liu , Da‐Qiang Yin , Shi‐Hai Cui , Lian‐Sheng Wang
Published: June 2005

The electrotopological state (E‐state) index was employed to characterize the structures of 51 substituted benzenes. Eleven E‐state indices of the compounds were calculated by the computer program developed in our laboratory. The method for variable selection and modeling based on prediction (VSMP) was used to select an optimal combination of the variables from 11 E‐state descriptors. Then the optimal descriptors were employed to model the relationship between the relative biodegradability of the substituted benzenes and their molecular structures. A novel 5‐descriptor linear model was developed and the model has a high quality with the correlation coefficient and the root mean square error in estimation step being 0.9378 and 0.35, respectively, and these in leave‐one‐out cross‐validation procedure being 0.9210 and 0.39, respectively.
Studies on the Stablest Geometries and CP Bonding Nature in P‐ylide CH2PH3and P‐ylide‐like Radical ·CHPH3
Authors: Yan‐Li Zeng , Ling‐Peng Meng , Shi‐Jun Zheng
Published: June 2005

Studies on the geometries, electronic structures and bonding nature of P‐ylide CH2PH3and P‐ylide‐like radical ·CHPH3have been carried out at the level of MP4(SDTQ)/6‐311++G(d,p) and B3LYP/6‐311++G(d,p). The CP bonding nature of them was discussed by means of topological analysis of electronic density. The following conclu‐sions were obtained: the CP bonding nature of the P‐ylide‐like radical is similar to that of the P‐ylide, and π bonds exist in both of them. But there are two electrons in the π bond of P‐ylide, while there is only one electron in the π bond of P‐ylide‐like radical,i.e., there is a single‐electron π bond in the P‐ylide‐like radical. The electron in the π bond of P‐ylide‐like radical appears mainly near the carbon atom. The bond CP in P‐ylide‐like radical is weaker than that in the corresponding product, ·CH2PH2.
Recycling Chiral Organocatalyst (4S)‐Phenoxy‐(S)‐proline for Direct Asymmetric Aldol Reaction in Ionic Liquid (bmim)PF6
Authors: Yan‐Hua Liu , Ya‐Wen Zhang , Yi‐Ping Ding , Zong‐Xuan Shen , Xiao‐Qing Luo
Published: June 2005

Room temperature ionic liquid (bmim)PF6 was evaluated for recycling an organocatalyst (4S)‐phenoxy‐(S)‐proline for direct asymmetric aldol reactions. The desired aldol products were obtained with good yields up to 93.2% and enantioselectivities up to 88.5%, and isolation of the products by simple extraction allowed recycling the ionic liquid containing the immobilized catalyst in subsequent reactions without significant decrease of yields and enantioselectivities.
Synthesis of Fragment Derivatives of Delta Sleep‐inducing Peptide (1‐4) Catalyzed by Enzymes in Organic Solvents
Authors: Hong‐Yan Shen , Gui‐Ling Tian , Yi‐Ying Hong , Heng Li , Yun‐Hua Ye
Published: June 2005

Synthesis of two fragment derivatives of delta sleep‐inducing peptide (DSIP) (1‐4), Boc‐Trp‐Ala‐Gly‐GlyNH‐NHPh (1) and Boc‐Trp‐Ala‐Gly‐GlyOEt (2), catalyzed by proteases via 2+2 or 1+3 synthetic routes with different protecting groups at C‐terminal in organic solvents was reported. The yield of N‐Boc tetrapeptide with phenylhy‐drazinyl protecting carboxyl group at C‐terminal (1) was higher than that of N‐Boc tetrapeptide ethyl ester (2) by2+2 route. The factors influencing the synthetic yield of the fragments of DSIP (1‐4) were discussed.
Detection and Analysis of Strong Oscillating Electric Fields in a Picosecond Laser Plasma with the Help of Plasma Satellites of X‐ray Spectral Lines
Authors: Belyaev V. S. , Kurilov A. S. , Matafonov A. P. , Vinogradov V. I. , Lisitsa V. S. , Gavrilenko V. P. , Faenov A. Ya. , Pikuz T. A. , Skobelev I. Yu. , Magunov A. I. , Pikuz S. A.
Published: June 2005

X‐ray lines of ions in a solid target interacting with picosecond laser pulses of the intensity ∼3 × 1017 W/cm2 were studied on the “Neodim” laser facility. We observed X‐ray Lyα emission spectra of hydrogen‐like fluorine ions. Satellite lines were also recorded, evidencing the presence of intense plasma oscillations with an amplitude of the electric field larger than 108 V/cm and a frequency of about 1015 s–1. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coulomb instability of dusty particle system in gas‐discharge plasma
Authors: Filinov V. S. , Petrov O. F. , Fortov V. E. , Molotkov V. I. , Khakhaev A. D. , Podrjadchikov S. F.
Published: June 2005

An effective anisotropic potential is proposed for the interaction between dust particles in a gas‐discharge plasma. In addition to the Coulomb repulsion this potential takes into account attraction due to the spatial positive plasma charge originating from focusing of the ionic fluxes by dusty particles. The time evolution of the dust particle kinetic and potential energies from random initial configurations have been investigated by the Brownian dynamics method. Results of our simulation showed that the attraction between dusty particles can be the main physical reason of formation and decay of classical bound dust particle pairs and many particle complexes with low potential energy, while the kinetic energy (temperature) of unbound dust particles and particle oscillating in bound complexes may increase on three order as observed in experiments. In the model without dust particle attraction the bound complexes are absent and increase of kinetic energy is much less pronounced. The influence of the high frequency and low frequency random‐charge fluctuations on the obtained results has been investigated. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface Tension of Plasma Sheath
Authors: Ignatov A. M. , Schram P. P. J. M. , Trigger S. A.
Published: June 2005

A simple model is developed for the self‐consistent charging of a dust layer in an electrode plasma sheath, as well as for the force balance in this layer. The anisotropy of the plasma pressure near the plasma boundary makes it possible to introduce the notion of surface tension. The equilibrium charge, the height at which the dust layer levitates above the electrode, and the plasma surface tension are calculated numerically as functions of the dust density. In all of the cases under analysis, the presence of dust is shown to increase the plasma surface tension, which indicates that the plasma sheath may become structurally unstable. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanisms for Generating High Energy Electron Beams by Intense Laser Radiation
Authors: Galkin A. L. , Shiryaev O. B. , Romanovsky M. Yu. , Korobkin V. V.
Published: June 2005

The possibility of electron acceleration during the laser radiation relativistic and charge‐displacement selfchanneling is studied theoretically. A new acceleration mechanism related to the formation of an ion cloud traveling in matter with the laser pulse (due to the effect of the ponderomotive force) is considered. The quasistationary electric and magnetic fields generated by the moving ion cloud can accelerate electrons to energies of tens of MeV and result in the formation of an electron beam going forward coaxially with the laser pulse. The angular distribution of accelerated electron calculated matches the experimental results found in the available publications. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurements of the Dust‐Ion Momentum Transfer Frequency and Ion Drag Force in Complex Plasmas
Authors: Yaroshenko V. V. , Ratynskaia S. , Khrapak S. A. , Thoma M. H. , Kretschmer M. , Morfill G. E.
Published: June 2005

A simple self‐consistent method to estimate the effect of the streaming ions on microparticles in a positive column of a dc discharge plasma is presented. The momentum transfer frequency in dust‐ion collisions and the ion drag force are determined within a wide range of gas pressures, p = 20–120 Pa. The method does not require a priory knowledge of the particle charge, but involves only the particle charge gradient which is recovered from the same experimental data. The method depends only on two experimental quantities: dust particle drift velocity and electric field, thus minimizing the errors in the estimates. Reasonable agreement is found between our force measurements and theoretical predictions, corresponding to the regime of moderate ion‐dust particle coupling. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Studies of Strongly Coupled Plasmas Using Intense Heavy Ion Beams at the Future FAIR Facility: the HEDgeHOB Collaboration
Authors: Tahir N. A. , Deutsch C. , Fortov V. E. , Gryaznov V. , Hoffmann D. H. H. , Lomonosov I. V. , Piriz A. R. , Shutov A. , Spiller P. , Temporal M. , Udrea S. , Varentsov D.
Published: June 2005

This paper shows with the help of numerical simulations that the high intensity bunched beam of uranium that will be available at the future FAIR (Facility for Antiprotons and Ion Research) facility [W.F. Henning, Nucl. Inst. Meth. B, 214 (2004) 211] at Darmstadt, will be a very efficient tool to create High‐Energy‐Density (HED) states in matter (including strongly coupled plasmas) in the laboratory. We have simulated hydrodynamic and thermodynamic response of targets made of different materials including aluminum and lead. These simulations have been carried out using a two‐dimensional hydrodynamic computer code, BIG‐2. Our simulations show that one can create a plasma with a plasma coupling parameter, Γ, of the order of 5. Such plasmas are believed to exist in stars, brown dwarfs and giant planets. Experimental study of such systems is therefore of great importance to our understanding of the universe. It has also been theoretically predicted that the stopping power of strongly coupled plasmas will be less than that of ideal plasmas. This could have very important implications for inertial confinement fusion energy production schemes. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Progress in Measurements of the Electrical Conductivity of Metal Plasmas
Authors: DeSilva A. W. , Rakhel A. D.
Published: June 2005

Progress in the exploding wire techniques for the measurements of the electrical conductivity of dense metal plasmas is reviewed. It is demonstrated that the data on the conductivity obtained by means of quite different techniques give results in good agreement. Recent results of direct measurements of the conductivity, internal energy and density of tungsten over a wide density and temperature ranges are presented. It is speculated that the data may lead to improvements in the conductivity and EOS databases. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Equation of State of Fluid Hydrogen
Authors: Kremp D. , Bezkrovniy V. , Kraeft W. D. , Schlanges M.
Published: June 2005

A review is given about some selected aspects of the development of the equation of state of hydrogen. Recent results are presented for low temperature fluid hydrogen. Reaction Ensemble Monte Carlo data determined thus are combined with Path Integral Monte Carlo results to give an Hugoniot covering the entire pressure range. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear Ionic Excitations, Dynamic Bound States, and Nonlinear Currents in a One‐dimensional Plasma
Authors: Chetverikov A. , Ebeling W. , Velarde M. G.
Published: June 2005

We study the role of nonlinear effects in a classical one‐dimensional model of a conducting electron–ion system. In particular we investigate the excitations of strongly nonlinear deformed phonons (cnoidal waves, solitons) on electric currents. We show that in a nonlinear lattice a new type of dynamic bound states of solitons and electrons (“solectrons”) may be formed. In our simulations we use Langevin dynamics with N = 10 ions and periodic boundary conditions. The electron‐ion interaction is modelled by screened Coulomb forces with appropriate cut‐off at small distance; the ion‐ion interaction is approximated by an exponential repulsion. Under the influence of a weak external electrical field, the charged particles and “solectrons” yield a stochastic current in the direction of the field. We study several mechanisms to generate and maintain the “solectrons”. Then we show how the system develops driven ionic solitons moving opposite to the field. Since the extra current driven by the solitons is (nearly) independent on the external field we find a strongly nonlinear current field characteristics corresponding for small fields to a highly conducting state. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Density functional calculations of the reflectivity of shocked xenon with ionization based gap corrections
Authors: Desjarlais M. P.
Published: June 2005

Experimental results [1] for the reflection coefficient of shock compressed xenon are compared with results from quantum molecular dynamics calculations with density functional theory (DFT). The real part of the optical conductivity is calculated within the Kubo‐Greenwood formalism and the Kramers‐Krönig relations are used to generate the reflectivity and other optical properties. Improved agreement over non‐ideal plasma theory [2] is found with the DFT calculations, but significant differences with the data remain. Since DFT in the various local density approximations tends to underestimate the band gap and overestimate the free electron population, we have used the ionizations from [2] to correct the DFT band gaps. This results in much improved agreement with the xenon reflectivity data and demonstrates a new approach to correcting DFT band gaps. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Relationship between the Structure and Magnetic Properties of Bioinspired Iron(ii/iii) Complexes with Schiff‐Base‐Like Chelate Ligands, Part I: Complexes with Dianionic [N4] Macrocycles
Authors: Weber Birgit , Käpplinger Indira , Görls Helmar , Jäger Ernst‐G.
Published: June 2005

The molecular structures and the spin ground‐state of the iron(ii/iii) complexesFe1,Fe2andFe3, which contain dianionic macrocyclic [N4] ligands derived from substituted acetylacetaldehydes and 1,2‐diamines, have been investigated by X‐ray analysis and temperature‐dependent susceptibility measurements, respectively. The iron(II) complexesFeII1(which is dimeric by intermolecular coordination of one peripheral carbonyl group),FeII1MeOH,(FeIIL)2dabco(L =1,2,3; dabco = 1,4‐diazabicyclo[2.2.2]octane) and the iron(III) complexFeIII1Clare pentacoordinate and have an intermediate‐spin ground‐state at room temperature (S= 1 for FeII;S= 3/2 for FeIII). The intermediate‐spin state was confirmed by DFT‐MO calculations forFeII1MeOHandFeIII1Cland is also in agreement with the Mössbauer data ofFeII1and ESR measurements ofFeIII1Cl. The iron centre inFeII2is nearly square‐planar and shows a strong decrease of the magnetic moment belowT≈ 250 K. This is probably due to anS= 0 toS= 1 spin‐crossover or, more likely, to intermolecular antiferromagnetic interactions (shortest Fe–Fe distance of 3.4 Å). A new pair of octahedral iron(ii/iii) complexes with an N‐heterocyclic axial ligand,FeII3(Py)2/[FeIII3(Py)2]PF6, could be crystallised. In contrast to the previously described pairsFeII1(Him)2/[FeIII1(Him)2]PF6andFeII2Py2/[FeIII2Py2]ClO4, the orientation of the planes of the axial ligands is nearly independent of the oxidation step of the central atom. Octahedral derivatives with biologically relevant anions as axial ligands have been crystallised for the first time, namely [BzEt3N][FeIII1(NCS)2], [Et4N][FeIII2(CN)2](H2O)0.5, Na[FeIII2(NO2)2](MeOH)2(H2O)0.5and [FeIII2(NO2)OH2](MeOH). The latter shows a magnetic moment ofμeff≈ 2.85 μBat room temperature, which decreases to 1.85 μBat lower temperature. This indicates an incompleteS= 1/2 toS= 3/2 spin‐crossover, which is probably due to the presence of H2O as a weak axial ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Multidimensional Cyanide‐Bridged Heterometallic FeII–CuI and Homometallic CuI Coordination Polymers from Solvothermal Reactions Involving either K3[Fe(CN)6] or KCN as the Source of Cyanide Anions
Authors: Colacio Enrique , Debdoubi Ahderrahmane , Kivekäs Raikko , Rodríguez Antonio
Published: June 2005

The reaction between K3[Fe(CN)6], CuCl2·2H2O and 1,10‐phenanthroline (phen) under hydrothermal conditions gives rise to the formation of the 3D cyanide‐bridged heterometallic FeII–CuI complex [Fe(CN)4(phen)2Cu2] (1). Its 3D network structure is constructed from two types of fused cyanide‐bridged 10‐ and 14‐metal‐membered centrosymmetric rings (Fe2Cu8 and Fe2Cu12), which are defined by the general sequences {(CuI)4‐FeII‐(CuI)4‐FeII} and {(CuI)6‐FeII‐(CuI)6‐FeII}, respectively. The copper(I) and iron(II) atoms exhibit distorted triangular planar and distorted octahedral coordination environments, respectively. Complex 1 is the first example of a 3D cyanide‐bridged bimetallic complex prepared by hydrothermal methods. The use of methanol as solvent, KCN as source of cyanide anions and 2,2',6,6'‐bipyrimidine as the bridging ligand results in the isolation of the 2D homometallic copper(I) complex [Cu2(CN)2(bpym)]·H2O (2). Its structure consists of neutral 2D (6,3) honeycomb layers in the ab plane made of fused Cu6(CN)4(bpym)2 rings, in which the copper(I) atoms exhibit a distorted tetrahedral geometry. The layers are interdigitated in such a way that the bpym ligands lie above and below the ring cavities of neighbouring networks, with an ABCD repeat sequence of layers. Water molecules are located in the free space between the A/D and B/C layers. Under the same conditions as used for 1, but with 4‐methyl‐2,2',6,6'‐bipyrimidine 2‐oxide instead of phen, the 3D complex [Cu2(CN)2(mbpym] (3) was obtained (mbpym = 4‐methyl‐2,2',6,6'‐bipyrimidine). During the reaction the oxygen atom of the N‐oxide group is eliminated and the novel ligand mpym formed. Its structure consists of distorted tetrahedral copper(I) atoms connected by cyanide and mpym bridging ligands to give rise to a 3D chiral network. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis, Structure and Spectroscopic Properties of Novel9,10‐Bis{[6‐(diphenylphosphanyl)‐2‐pyridylmethyl]propylaminomethyl}anthracene‐Bridged Group 11 Metal (M = CuI and AgI) Dinuclear Complexes
Authors: Xu Hu , Xu Feng‐Bo , Li Qing‐Shan , Duo Wei‐Guo , Song Hai‐Bin , Zhang Zheng‐Zhi
Published: June 2005

Dinuclear complexes [M2(μ‐BPNNAn)]X2 (M = CuI, X = ClO4– 1, X = BF4– 2; M = AgI, X = BF4– 3, X = ClO4– 4) have been prepared by treating 9,10‐bis{[6‐(diphenylphosphanyl)‐2‐pyridylmethyl]propylaminomethyl}anthracene (BPNNAn) with M(CH3CN)4X in CH2Cl2. The structures of complexes 1, 2 and 3 have been determined by single‐crystal X‐ray diffraction studies. In the complexes, BPNNAn acts as a chelating ligand and two metal ions riding on two bridgehead carbon atoms in the anthracene group leads to the deformation of the anthracenyl ring. The Cu–Arene charge transfer interaction is observed from the nonfluorescent emission of Cu complex 1, while the Ag complex 3 exhibits dual emission at high concentrations in a CH2Cl2 solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Fenton Reaction in Aerated Aqueous Solutions Revisited
Authors: Rachmilovich‐Calis Sandra , Masarwa Alexandra , Meyerstein Naomi , Meyerstein Dan
Published: June 2005

The oxidation of alcohols in aerated acidic aqueous solutions by the Fenton reagent is a chain reaction. The length of the chain depends linearly on the number of CHnOR (n = 1 or 2) groups in the alcohol. The reaction is accelerated by increasing the concentration of Fe(H2O)62+, but this cation is also active in at least one of the termination steps of the chain reaction. Addition of ethanol to a solution containing sucrose shortens the chain length. Saturation with dioxygen, instead of air, increases the chain length. An increase in alcohol concentration increases the chain length up to a limiting value. A complicated mechanism, which is in agreement with all these observations, is proposed. However, efforts to simulate the mechanism succeed only in simulating the Fe(H2O)63+ yield, but indicate that the observed process is considerably faster than the predicted one. In the latter the rate‐determining step is the Fenton reaction, the rate constant of which is well known. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Ethylene Homo‐ and Copolymerization Activity of a Series of [ONNO]‐Type Amine Bis(phenolate) Based Vanadium(II–V) Catalysts
Authors: Lorber Christian , Wolff Fabien , Choukroun Robert , Vendier Laure
Published: June 2005

The synthesis and structural characterization of new paramagnetic amine bis(phenolate) [ONNO]‐vanadium(III) and‐vanadium(II) complexes, VIII(acac)[ONNO], VIII(Cl)(THF)[ONNO], and VII(TMEDA)[ONNO], is described. These compounds complete the family of [ONNO]‐vanadium(IV/V) complexes previously reported. The members of the [ONNO]‐vanadium family at various oxidation states that range from vanadium(II) to vanadium(V), in association with EtAlCl2 cocatalyst, were studied in the polymerization of ethylene and in the copolymerizations of ethylene‐1‐hexene and ethylene‐norbornene. Poly(ethylene‐co‐1‐hexene) and poly(ethylene‐co‐norbornene) were produced with co‐monomer content of up to 11 mol‐% and 29 mol‐% for 1‐hexene and norbornene, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)