bluuebunny/crossref_metadata_2025_split huggingface dataset:
Palladium(II) Complexes Containing P∼N∼O Donors. Preparation and Reactivity
Authors: Shi Ping‐Yung , Liu Yi‐Hong , Peng Shie‐Ming , Liu Shiuh‐Tzung 
Published: May 2015

AbstractPalladium complexes [(P∼N∼O)PdR]BF4 containing imine‐phosphine‐ether tridentate donor were prepared. The behavior of an ether donor, a hemi‐labile one, influences the coordination mode of a carbon ligand around the metal center. Reaction of excess styrene with [(P∼N∼O)PdMe]BF4 results in the formation of [(P∼N∼O)Pd(η3‐CH(CH3)C6H5)]BF4, which is characterized by spectral and crystal structural determination. Copolymerization of olefin and carbon monoxide catalyzed by [(P∼N∼O)PdMe]BF4 is addressed.
Reactions of Sydnone Rings with Cyclopentadiene and/or Dicyclopentadiene: Formation of Pyrazole by Utilization of Sydnones as the Synthetic Presursors
Authors: Lin Shaw‐Tao , Tien Hsien‐Ju , Huang Shul‐Man , Chen Jinn‐Tsair , Shu Jinn‐Tsair 
Published: May 2015

AbstractSydnone can be converted to pyrazoles by reacting with cyclopentadiene. These products result from direct reaction of sydnone with either cyclopentadiene or dicyclopentadiene. Among the four products, two of the compounds are verified by X‐ray diffraction analysis.
Direct Oxidative Amidation of Aldoses by Iodine in Ammonia Water
Authors: Chen Ming‐Yi , Hsu Jue‐Liang , Shie Jiun‐Jie , Fang Jim‐Min 
Published: May 2015

AbstractAldopentoses, aldohexoses and the benzylated derivatives reacted with iodine in ammonia water at room temperature to give their corresponding saccharide amides in high yields. The reactions proceeded with oxidation of the aldose hemiacetals by iodine to generate the saccharide lactone intermediates, which underwent ammonolysis in situ to give the saccharide amides.
Cytotoxic and Antiplatelet Aggregation Principles of Ruta Graveolens
Authors: Wu Tian‐Shung , Shi Li‐Shian , Wang Jhi‐Joung , Iou Song‐Chou , Chang Hsien‐Chang , Chen Yuh‐Pan , Kuo Yao‐Haur , Chang Ya‐Ling , Tenge Che‐Ming 
Published: May 2015

AbstractNineteen compounds have been isolated from the methanol extract of the root and aerial parts of Ruta graveolens. The structural elucidation of these isolated compounds were determined by the spectroscopic methods and/or comparison of the physical data with literature values. Their antiplatelet aggregation and cytotoxic activities were examined to find potent antiplatelet aggregation and cytotoxic compounds from natural resources. Among them, dictamine (5), skimmianine (7), psoralen (8), chalepensin (12), clausindin (13), and graveolinine (16) showed significant inhibition of platelet aggregation, induced by arachidonic acid and collagen. Arborinine (2), dictamine (5), isopimpinellin (11), clausindin (13), and graveoline (17) exhibited cytotoxic activity against KB, Hela, DLD, NCI and Hepa tumor cell lines.
Rice Bran as an Excellent Sorbent for Heavy Metals from Aqueous Media, 2. Determination of Related Parameters
Authors: Farajzadeh Mir Ali , Vardast Mohammad Reza 
Published: May 2015

AbstractIn part 2 of this report related parameters of the rice bran (as a sorbent of heavy metals) such as exchange capacity, distribution coefficients and isotherms, etc. were studied. The obtained results show that selectivity of the bran towards heavy metals such as Cu(II), Cd(II), Fe(III), Ni(II), Zn(II) and Pb(II) is very high. Also, distribution coefficients between aqueous solution and bran are more than 104 so that all cations are completely adsorbed by the bran in relatively low concentrations. The principal advantages of this sorbent are as follows: high efficiency, very high exchanging speed, cheapness (in comparison with conventional resins), performance in batch and continuous conditions and producing no environmental pollution. The only disadvantage of the bran is low exchanging capacity for some elements (but for lead it is comparable to classical resins); however, it is able to eliminate heavy metals in mg/L level and above. On the other hand, due to low cost of bran and high cost of recovery of ion exchangers there is no necessity to recover the bran. Reproducibility of the proposed method in removal of heavy metals is excellent and the relative standard deviations for eight repeated removals for all cations with the exception of iron are less than 1%.
First and Efficient Method for Reduction of Aliphatic and Aromatic Nitro Compounds with Zinc Borohydride as Pyridine Zinc Tetrahydroborato Complex: A New Stable Ligand‐Metal Borohydride
Authors: Zeynizadeh Behzad , Zahmatkesh Karam 
Published: May 2015

AbstractPyridine zinc tetrahydroborate, [(Py)Zn(BH4)2], as a new stable ligand‐metal borohydride, is prepared quantitatively by complexation of 1:1 zinc borohydride and pyridine at room temperature. This reagent efficiently reduces different aromatic and aliphatic nitro compounds to their primary amines in refluxing THF. In addition, the reduction shows chemoselectivity for aliphatic nitro compounds over the aromatic nitro compounds.
Synthesis of 8‐Desoxythunberginol A and (±)‐8‐Desoxy‐3,4‐Dihydrothunberginol A
Authors: Saeed Aamer 
Published: May 2015

AbstractA two step synthesis of title isocoumarin isolated from Homalium longifolium and its conversion into corresponding 3,4‐dihydroisocoumarin has been described. 3,4‐Dimethoxybenzoyl chloride on condensation with homophthalic acid afforded 3‐(3′,4′‐dimethoxyphenyl)isocoumarin which was demethylated to furnish the 8‐desoxythunberginol A, whereas its sequential saponification, reduction and demethylation yielded the (±)‐8‐desoxy‐3,4‐dihydrothunberginol A. The synthesized compounds were examined in vitro for antibacterial activity.
Synthesis, Characterization and Bio‐activities of Novel Organotin(IV) Complexes with N‐Phthaloyl‐D‐valine
Authors: Ashfaq Muhammad , Baloch Musa Kaleem , Majeed Abdul , Khanzada Abdul Wahab Khan , Shah Wali Ullah 
Published: May 2015

AbstractThe synthesis and spectroscopic characterization of novel organotin(IV) complexes are described. The monomeric compound possesses trans octahedral, and the dimeric complex is of six‐coordinated skew trapezoidal bipyramidal geometry. The triorganotin(IV) complexes are assigned a polymeric trigonal bipyramidal and a tetrahedral structure. The ED50 test showed toxicity to brine shrimp naupli and bio‐activities tests of the compounds exhibited antibacterial, antifungal and excellent anti‐tumour activities.
New Annulation Techniques; Condensations of Phosphonium Ylides and Substituted 2H‐Pyran‐5‐carboxylates; Preparation of Cyclohexenonedicarboxylates and Cyclohexadienedicarboxylates
Authors: Moorhoff Cornelis M. 
Published: May 2015

AbstractSubstituted alkyl 2H‐pyran‐5‐carboxylates condensed with alkyl 3‐oxo‐4‐(triphenylphosphoranylidene)butanoate and alkyl 4‐(triphenylphosphoranylidene)‐2‐butenoate to form substituted 2‐vinyl‐6‐oxo‐4‐cyclohexene‐1,3‐dicarboxylates, some of which showed ecto‐parasiticidal activity in pets and cattle, and substituted 2‐vinyl‐3,5‐cyclohexadiene‐1,3‐dicarboxylates, respectively. The last mentioned product is in marked contrast to the product obtained using the corresponding arsonium analogue.
Solvent‐Free Synthesis of N,N′‐Diarylureas Using Microwave Technology
Authors: Sun Ting , Li Jing , Wang Yu‐Lu 
Published: May 2015

AbstractA simple and rapid solvent‐free synthesis of N,N′‐diarylureas in a microwave oven has been reported for the first time. Nine compounds were synthesized. The reaction time is short (2∼5 min) and gives excellent yield (80–95%).
A New Method for the Synthesis of Acyl‐diazenes Using NaNO2‐Ac2O
Authors: Li Jian‐Ping , Liu Ping , Xue Wan‐Xin , Wang Yu‐Lu 
Published: May 2015

AbstractAn efficient and convenient method for the synthesis of acyl‐diazenes from acylhydrazines using NaNO2‐acetic anhydride as a novel oxidant agent is reported. The reaction gives excellent yields and the reaction time is not long.
Chemical Composition and the Origin of Suspension Particles in Liang‐Dong Bay (Yin‐Yang Sea), Northern Taiwan
Authors: Fang Jiann‐Neng , Yu Being‐Sheng , Chen Yaw‐Lin , Song Sheng‐Rong , Lo Huann‐Jih , Lin I‐Chieh , Liu Chia‐Mei , Liu Ya‐Jiun 
Published: May 2015

AbstractA phenomenon of mixing blue and brown seawater, called “Yin‐Yang Sea”, has existed for decades in Liang‐Dong Bay. In order to determine the chemical composition and origin of pollutants in the bay, each of 5 water samples from the stream and bay were collected for chemical analyses. Meanwhile, suspension particles in the bay, the sediments on the bottom of bay and the precipitation on the bottom of the stream were also collected for chemical, X‐ray diffraction and particle size analyses.The suspension particles are amorphous and are predominantly composed of Fe(OH)3. This is showen by the solubility products of water samples in the bay being higher than the ksp of Fe(OH)3. The deposits on the bottom of the stream also show similar results. However, the chemical concentrations of major ions, e.g. Na+, K+, Ca+2, Mg+2, Cl− and SO4−2, are much higher in the bay water than of the stream water. Nevertheless, Fe+2, Mn+2, Cu+2 and Si+4 show positive anomalies in the lower stream where the abandoned pits are located. Thus, it is assumed that minerals in the pits, such as pyrite and marcasite, are the main source supplying iron through weathering. Iron released by minerals is carried by the stream and arrives in the bay in hours. Since the oxidation rate becomes very slow in the bay because of the effects of salts and neutral pH values, most of the particles of Fe(OH)3 form in the bay gradually.
Single Molecule Spectroscopy
Authors: Latychevskaia Tatiana Y U. , Liang Kuo Kan , Hayashi Michitoshi , Chang Chung‐Hung , Renn Alois , Wild Ur S. P. , Hsu Jui‐Hung , Chang Ta‐Chau , Lin Sheng Hsien 
Published: May 2015

AbstractSingle molecular experiments carried out in the group of Prof. Wild in ETH Zurich, as well as the experimental and theoretical studies of several research groups in Taiwan, have been summarized in this review. It is shown that with the contemporary technologies, single molecular experiments can be carried out under a broad range of physical conditions. These includes low and room temperatures; in vacuum, in solution, in the air, or with specific pressure applied on the sample; in applied direct‐current or alternating‐current electric fields; on molecules in solid matrices, in gel, or even functioning biomolecules in vitro. Theoretical efforts have been able to help identifying the interactions of single molecules with their surroundings that modulate their static or time‐resolved spectroscopic properties. The joint experimental and theoretical effort to develop the research techniques in single molecular experiments is shown to be fruitful, and future works in this direction are important for many fields in chemistry, physics, and biology.
A Theoretical Study of N‐methlyformamide Photolysis
Authors: Chen Xue‐Bo , He Hong‐Yuan , Fang Wei‐Hai 
Published: May 2015

AbstractThe potential energy surfaces for N‐methlyformamide(HCONHCH3) dissociation into HCO + NHCH3 and CONHCH3 + H in the ground and lowest triplet states have been characterized with DFT, MP2 and CASSCF methods with the cc‐pVDZ basis set, while the S1 potential energy surfaces for the dissociation reactions were determined by the CASSCF/cc‐pVDZ optimizations followed by MRSDCI single‐point calculations. The mechanism of the HCONHCH3 photodissociation has been elucidated on the basis of the computed potential energy surfaces and surface crossing points.
Bifurcation Analysis of the Trans ↔ Cis Rotation of Monorotor Molecules
Authors: Cheng Hsiu‐Yao , Lai Chi‐Jung , Chang Shyang 
Published: May 2015

AbstractThe bifurcation analyses of the internal rotation of three different series of monorotor molecules are investigated in this paper. Our results indicate that the types of catastrophe and topological regions are related to the generic form of potential energy function and the critical points. Namely, when the double‐barrier energy function is represented as the third‐order generic polynomial of the reduced reaction coordinate, the process is isomorphic to the elementary fold catastrophe. Similarly, when the triple‐barrier energy functions are represented as the fourth‐order generic polynomial of the reduced reaction coordinate, the process is isomorphic to the elementary cusp catastrophe.
Theoretical Study of the X+YCl (X, Y=H, D) Reactions
Authors: Yao Li , Han Ke‐Li , Song He‐Shan , Zhang Dong‐Hui 
Published: May 2015

AbstractTime‐dependent wave packet calculations for the reaction H+HCl and its isotopic reactions are carried out on the potential energy surface (PES) of Bian and Werner (BW2) [Bain, W.; Werner, H.‐J. J. Chem. Phys. 2000, 112, 220]. Reaction probabilities for the exchanged and abstraction channels are calculated from various initial rotational states of the reagent. Those have then been used to estimate reaction cross sections and rate constants which also are calculated and explained by the zero‐point energy and the tunneling effect. The results of this work were compared with that of previous quasiclassical trajectory calculations and reaction dynamics experiments on the abstraction channel. In addition, the calculated rate constants are in reasonably good agreement with experimental measurements for both channels.
Computations on a Series of Substituted Quinolines
Authors: Slanina Zdenêk , Hsu Ming‐Ann , Chow Tahsin J. 
Published: May 2015

AbstractComputations are reported for a series of eight substituted quinolines. Their computed HOMO‐LUMO gaps have particularly been of interest as they can be measured and should correlate with some physico‐chemical properties. Structures and energetics of the selected substituted quinolines have been evaluated at several levels of theory. Interesting deviations from planarity are found in some cases. There is a good agreement with available observed thermochemical data. Effects of various computational approximations are discussed.
Clustering, Saturated Vapors, and the Atmosphere
Authors: Slanina Zdenêk 
Published: May 2015

AbstractRecent heuristic computational findings of temperature increase of clustering degree in several, quite different saturated vapors are analyzed. A thermodynamic proof is presented, showing that this event should be rather common. Illustrations are primarily based on saturated steam and also on carbon vapor. Consequences for the atmosphere are discussed.
Computation of the Protein Structure Entropy and Its Applications to Protein Folding Processes
Authors: Chan Chen‐Hsiung , Lyu Ping‐Chiang , Hwang Jenn‐Kang 
Published: May 2015

AbstractWe have developed a general method to compute the structure entropies of protein sequences. Structure entropy gives a quantitative measure of structure conservation. This relationship is similar to that between sequence entropy and sequence conservation. Experimental studies in protein folding have suggested that residues relevant to protein folding, or the so‐called “hot spot” residues, are usually structurally conserved, though not necessarily conserved in sequences. Hence, the ability to compute structure entropy can help identify important residues related to protein folding. In this work, we have applied our approach to several model proteins frequently used in protein folding experiments. Our results suggest a close relationship between the structure entropies of residues and their rates of amide proton exchange, and we are able to identity regions of residues that are important in protein folding.
Theoretical Study of the Fragmentation of Glycine Radical Cation
Authors: Lu Hsiu‐Feng , Li Feng‐Yin , Lin S. H. 
Published: May 2015

AbstractUsing the CCSD(T)//B3LYP method with 6–31+G(d,p) basis sets, we report the preliminary result about four fragmentation reactions of glycine cation radical and propose possible mechanisms for several ion products found in glycine mass spectrum. There are intermediates in the reaction pathway of the fragmentation of glycine radical cation. Our result shows that the dominant fragmentation process arises from the Cα‐R cleavage by losing COOH, corresponding to the m/z 30 peck (NH2CH2+). There are two reactions generating this fragment in the four fragmentation reactions discussed in this report.
σπ Scheme in Atom‐bond Electronegativity Equalization Method
Authors: Yang Zhong‐Zhi , Cong Yao , Zhao Dong‐Xia , Wang Chang‐Cheng , Bao Xin‐He 
Published: May 2015

AbstractAlthough, as we know, the traditional ab initio quantum chemical methods can deal with molecules of medium size, it is still a tremendous task to treat very big organic and biological systems. So even today it is still valuable to develop some meaningful relatively simple methods, such as EEM or ABEEM, to see how well and to what extent those kinds of methods can be employed with a huge savings of time to study very large systems. This kind of effort, including what has been done in this paper, may continue for quite a long period, especially considering dynamic problems in the near future. We will develop an atom‐bond electronegativity equalization method plus σπ (ABEEM σπ) scheme on the basis of DFT, in which the structure of double bond is explicitly treated in the electronegativity equalization method. In this scheme, the effective electronegativity of a region can be expressed as one valence‐state electronegativity (χ*) term, one valence‐state hardness (η*) term, and some other contributing terms coming from other regions' charges in the molecule. By dealing with more than 200 molecules, the parameters χ*, η*, C, and D in the expression of electronegativity are determined through a regression and least‐squares optimization procedure, and their meaning is also discussed. As testing examples, the ABEEM σπ scheme is used to calculate the charge distributions of C18N3O3H27, C15NO2H21, and thyrotropin‐releasing hormone (TRH), and the results show good agreement with those obtained by the ab initio method. However, this scheme is far more time saving and computational‐source saving compared to the conventional ab initio method. All of this indicates that the ABEEM σπ scheme is a reasonable and potential tool for predicting the properties of very large organic and biological systems such as poly‐peptides and proteins, etc.
Preparation and Application of Cholesteryl‐Macrocyclic Polyether Liquid Crystals and Surfactants
Authors: Lee Juei‐Ling , Shen Ya‐Chi , Shih Jeng‐Shong 
Published: May 2015

AbstractMacrocyclic polyethers containing a cholesteryl moiety, e.g., cholesteryl benzo‐15‐crown‐5 (C27H45OOC‐B15C5) and cholesteryl cryptand22 (C27H45OOC‐Cryptand22), were synthesized. The cholesteryl crown ether C27H45OOC‐B15C5 showed liquid crystal characteristics which were observed by polarizing microscopy. In contrast, the cholesteryl cryptand C27H45OOC‐Cryptand22 showed no liquid crystal characteristics. The doping effect of inorganic salts on the liquid crystal formation of cholesteryl benzo‐15‐crown‐5 was also investigated, revealing that the addition of salts resulted in narrower liquid crystal temperature ranges. Both cholesteryl cryptand C27H45OOC‐Cryptand22 and cholesteryl crown ether C27H45OOC‐B15C5 also exhibited the distinctive characteristics of surfactants in solutions. Fluorescence probe of pyrene and surface tension measurement were applied as sensitive tools to study the formation of the micelles and determine the critical micellar concentration (CMC) of the cholesteryl cryptand and crown ether surfactants. The salt effect on the CMC of the cholesteryl cryptand surfactant was also investigated and is discussed. Furthermore, the cholesteryl benzo‐15‐crown‐5 was successfully employed as a quite good phase transfer catalyst for the oxidation of alcohols, e.g., benzhydrol, with NaMnO4 as an oxidant. Effects of temperature, solvent and concentration of the crown ether catalyst on the oxidation of benzhydrol were also investigated.
Immobilization of a Monolayer of Bovine Serum Albumin on Gold Nanoparticles for Stereo‐specified Recognition of Dansyl‐norvaline
Authors: Liu Fu‐Ken , Wei Guor‐Tzo , Cheng Fu‐Chou 
Published: May 2015

AbstractThe assembly strategy to prepare a monolayer of bovine serum albumin on the surface of silica gel supported gold nanoparticles is described. The stereo‐specific recognition ability of this material was evaluated by enantioresolution of Dansyl‐norvaline. For enantiomeric separation, the influences of buffer concentration and the concentration of organic modifier on the separation performance were investigated. A better separation in terms of enantioresolution and peak shape was found with the phosphate concentration at 30 mM. Moreover, the peak shape and resolution can be improved by the addition of methanol solution. Enantioresolution of Dansyl‐norvaline was obtained from this material at optimized conditions. It appears that the immobilization of a monolayer of bovine serum albumin on gold nanoparticles as the chiral selector of Dansyl‐derivative amino acid is promising.
The Torsional Stability Around a Single Bond Analyzed by Extended Hückel Orbital Forces
Authors: Federico Eisner S. , Jorge Ricardo Letelier D. 
Published: May 2015

AbstractA simple pencil and paper method to calculate the forces acting on individual atoms in a molecule, due to the electrons in the different populated molecular orbitals, has been developed within the Extended Hückel formalism. The method is applied to study the torsional stability around a single bond of some simple molecules. The results show good agreement with the experimental evidence of stable conformers.
Preparation and Characterization of Trimethylsilylpyridylacetylene Bridged, Dicobalt Carbonyl Complexes Containing Bis(diphenylphosphino)methylene or Bis(diphenylphosphino)ethylene Ligand
Authors: Hong Fung‐E , Chang Yu‐Chang , Chen Cheng‐Wei , Huang Yi‐Luen 
Published: May 2015

AbstractReaction of an alkyne‐bridged dicobalt complex, [Co2(CO)6(μ‐Me3SiC=Cpy)] 4, with bis(diphenylphosphino)methylene (DPPM) or bis(diphenylphosphino)ethylene (DPPE) in THF at 55 °C yielded a DPPM or DPPE doubly bridged dicobalt compound, [{μ‐P,P‐PPh2CH2PPh2}Co2(CO)4(μ‐Me3SiC=Cpy)] 5 or [{μ‐P,P‐PPh2CH2CH2PPh2}Co2(CO)4(μ‐Me3SiC≡Cpy)] 6. Compound 5 and 6 were characterized by spectroscopic means as well as X‐ray crystal structure determination.
Cyclic Voltammetric and Ac Impedance Behavior of TiO2 Electrodes under UV Illumination
Authors: Cui Xiaoli , Jiang Zhiyu 
Published: May 2015

AbstractElectrochemical behavior of an ITO/TiO2 electrode both under ultraviolet (UV) illumination and in the dark was investigated using the methods of cyclic voltammetry and ac impedance spectroscopy. A new oxidative peak is observed at 0.15 V when the TiO2 electrode was illuminated by UV light for a certain time. The peak current and the anodic photocurrent increased with the increase of UV light intensity. It is assumed that the new peak belonging to the oxidation of Ti3+, which was formed on the electrode surface during the UV illumination. It is also found that the apparent resistance was decreased but the capacitance was increased when the TiO2 electrode was illuminated by UV light according to the measurement results of ac impedance. Based on the results in this paper, it was directly proved that Ti3+ was actually formed when the electrode was irradiated by UV light.