bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction and Interfacial Molecular Recognition of Calix [4] arene Derivatives Bearing Nucleobases for Complementary Nucleoside
Authors: Zhen‐Sheng Wang , Guo‐Yuan Lu , Xin Sheng , Xun Guo , Chuan‐Ming Jin 
Published: September 2010

AbstractThe p‐tert‐butyl calix[4] arene derivatives la with uracils and lb with adenines at the lower rim were synthesized. The Interaction between la and lb in CDCl3 solution was demonstrated by 1H NMR spectra. The interfacial molecular recognitions of la and lb for the complementary nucleosides in aqueous subphases were investigated by Langmuir‐Blodgett technique.
Synthesis of Chlorin‐enediyne Dyads by Palladium‐catalyzed Coupling Reaction
Authors: Jin‐Jun Wang , Jun‐Gang Yin , Xu‐Ran Wu , Yan Zhao , Bao‐An Gong , Guang‐Fan Han , Key Shim Young 
Published: September 2010

AbstractMethyl 9‐ethylenedioxpyropheophorbide‐d was prepared from methyl pyropheophorbide‐a by protection of cyclic ketone with ethylene glycol, and oxidation with OsO4 in vinyl group at 2‐position. The terminal alkyne was introduced into chlorin chromophore by Grignard reaction, and the enediyne moiety was constructed by a palladium‐catalyzed coupling reaction with (Z)‐chloroenynes.
Microcalorimetric Studies of the Toxic Action of La3+ on Halobacterium Halobium R1 Growth
Authors: Peng Liu , Yi Liu , You‐Gui Chen , Song‐Sheng Qu , Zhi‐Xiong Xie , Ru‐Ming Zhao , Ping Shen 
Published: September 2010

AbstractA microcalorimetric technique was used to evaluate the influence of La3+ on Halobacterium halobium Rl growth. By means of LKB‐2277 bioactivity monitor, ampoule method at 37 °C, the thermogenic curves of Halobacterium halobium R1 growth were obtained. In order to analyze the results, the maximum power Pm and the growth rate constants k were determined, showing that values of Pm and k are linked to the concentration of La3+. Addition of low concentration of La3+ can cause a decrease of the maximum heat production and growth rate constant. However, high concentration of La3+ may promote growth of Halobacterium halobium R1, but at much higher concentration of La3+, the growth of Halobacterium halobium R1 is inhibited again. For comparison, the shapes of Halobacterium halobium R1 cell were observed by means of transmission electron microscope. According to the thermogenic curves and TEM photos of Halobacterium halobium R1 under different conditions, it is clear that metabolic mechanism of Halobacterium halobium R1 growth is changed with the addition of La3+.
One‐pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐one Using TsOH as a Catalyst under Microwave Irradiation
Authors: Shn‐Jiang Tu , Fang Fang , Chun‐Bao Miao , Hong Jiang , Da‐Qing Shi 
Published: September 2010

AbstractA series of Biginelli compounds was synthesized using TsOH as a catalyst under microwave irradiation. This simple method provided the title compounds in 86%–98% yields by the reaction of aromatic aldehydes with 1,3‐carbonyl compound and urea. The structure of 4o was determined by single crystal X‐ray diffraction analysis.
CD Spectroscopic Study on the Molecular Recognition of Chiral Salen‐Metal Complexes
Authors: Liu Tao , Ruan Wen‐Juan , Nan Jing , Zhu Zhi‐Ang 
Published: September 2010

AbstractThe molecular recognition behavior of the chiral salen‐metal complexes towards guest molecules, such as imidazole derivatives and amino‐acid ester, was systematically investigated by means of circular dichroism (CD) spectra. The coordination numbers of the host‐guest complexes as well as the recognition capability of the salen‐metal complexes were explained by character and intensity analyses of the CD spectra.
Mercaptolysis of the E/F Rings of Steroidal Sapogenins: A Concise Synthesis of Δ20(22)‐Furostene‐26‐thioethers
Authors: Tian Wei‐Sheng , Guan Hui‐Ping , Pan Xin‐Fu 
Published: September 2010

AbstractLewis acid catalyzed mercaptolysis of steroidal sapogenins was reinvestigated. Besides obtaining the reported 26‐thioacetals 5 under milder conditions, a new type of compounds Δ20(22)‐furostene‐26‐thioethers 6 were also synthesized through the mercaptolysis of steroidal sapogenins, which can be used to the synthesis of the steroidal molecule with side chains.
Studies Towards the Total Synthesis of Methyl Isosartortuoate: The Synthesis of a Cyclic Precusor of the Diene Unit
Authors: Liu Peng , Liao Xi‐Bin , Xu Xing‐Xiang 
Published: September 2010

AbstractThe preparation of the key intermediate 4 of the methyl isosartortuoate is described. The macrocyclization was completed through an intramolecular [2, 3]‐Wittig ring contraction. The four necessary stereogenic carbons were established by Sharp‐less asymmetric AE and AD reaction.
Sn‐Mediated Catalytic Asymmetric Reduction of Carbonyl Groups by Sodium Borohydride (or Sodium Borodeuteride)
Authors: Zhao Gang , Hu Jian‐Bing 
Published: September 2010

AbstractTwo remarkable reducing agents NaBH4 (or NaBD4)/SnCl2(or SnCl4·2Et2O) with chiral ligands are applied to the asymmetric reduction of carbonyl compounds with excellent chemical yields and enantioselective excesses.
Highly Chemical and Regio‐selective Catalytic Oxidation with a Novel Manganese Catalyst
Authors: Liu Bin , Chen Yi , Yu Cheng‐Zhi , Shen Zheng‐Wu 
Published: September 2010

AbstractThe chemical selectivity of a novel active manganese compound [MnIV/2μ‐O)3(TMTACN)2](PF6)2(1) in catalytic oxidation reactions depended on the structure of substrates and 1 was able to catalyze the oxidation of toluene into benzaldehyde and/or benzoic acid under very mild conditions. The following results were obtained; (1) The selectivity of the oxidation depended on the electronic density of double bonds. Reactivity was absent when strong electron‐witherawing groups were conjugated with double bonds. (2) Allylic oxidation reactions mostly take place when double bond is present inside a ring system, whilst epoxidation reactions occur when the alkene moiety is part of linear chain. (3) In ring systems, the methylene group was more likely to be oxidized than the methyl group on allylic position. As expected, the C—H bonds at the bridgeheads were unreactive. The secondary hydroxyl groups are more easily to be oxidized than the primary hydroxyl groups.
Asymmetric Syntheses Aided by Biocatalysts
Authors: Pei‐Ran Chen, , Jian‐Xin Gu, , Zbi‐Liang Wei, , Shi‐Qing Han, , Zn‐Yi Li, , Guo‐Qiang Lin, 
Published: September 2010

AbstractThis article summarizes the achievements of the authors' group in the area of biocatalyst‐catalyzed organic reactions in recent 10 years. A strain ofGeotrichumsp. obtained by screening is capable of stereoselectively reducing a number of carbonyl compounds. In many cases, the stereochemistry is complementary with that obtained by baker' s yeast. Therefore, this microorganism provides a useful pathway to the preparation of alcohol compounds with specific configurations. On the other hand, a number of plant sources have been screened for oxynitrilases and the hydrocyanation reactions of various arylcarboxaldehydes have been investigated. A “micro‐aqueous reaction system” was invented, by which a series of novel optically active cyanohydrins were prepared. On this basis, a high through‐put continuous reaction system has been designed. This paper also describes examples of the syntheses of bio‐active compounds by using the optically active compounds obtained from the above‐mentioned catalytic reactions as precursors.
Low Temperature Solvent Evaporation‐induced Crystallization Synthesis of Nanocrystalline TiO2 Photocatalyst
Authors: Jia‐Guo Yu , Jimmy C Yu 
Published: September 2010

AbstractA novel and efficient methodology for obtaining highly active photocatalyst of bi‐phase TiO2 with small particle size and high specific surface area was developed by solvent evaporation‐induced crystallization (SEIC) method at low temperature. The prepared TiO2 powder was characterized with X‐ray diffraction (XRD), transmission electron microscopy (TEM) and BET surface areas. The photocatalytic activity was evaluated by the photocatalytic oxidation of acetone in air. The results showed that the photocatalytic activity of the TiO2 powder prepared by this method approached that of Degussa P25. This may be attributed to the fact that the prepared TIO2 powder had larger specific surface areas (265 nr2. g−1) and smaller crystallite size (about 5 nm), but relatively low crystallinity, as compared with Degussa P25.
Crystal Structure of Adduct 2‐Phenyl‐imidazo[4,5‐/]1,10‐phenanthroline Methanol
Authors: Hui‐Wen Lin , Wen‐Xiang Zhu 
Published: September 2010

AbstractThe structure of the title adduct comprises a phenanthroline derivative 2‐phenyl‐imidazo[4,5‐/]1,10‐phenanthroline and a methanol. The composition of the crystalline adduct was characterized as C19H12N4 CH3OH. It belongs to orthorhombic system, space group Pna21 with a = 1.3693(4) nm, b = 2.2988(7) nm, c =0.51338(15) nm, V = 1.6160(8) nm3, Z = 4, and final R1 = 0.0423, wR2 = 0.1012. Crystal structure shows that all the 19 carbon atoms and 4 nitrogen atoms are coplanar. The bond length data indicated that a very extensive conjugation system was formed. This conjugation makes the compound being a potentially excellent energy transformer used for luminescent materials.
Direct Electron Transfer between Glucose Oxidase and Multi‐walled Carbon Nanotubes
Authors: Jin‐Zhong Xu, , Jun‐Jie Zhu, , Qiang Wu, , Zheng Hu, , Hong‐Yuan Chen, 
Published: September 2010

AbstractThe direct electrochemical behavior between the glucose oxidase (GOD) and the multi‐walled carbon nanotubes (MWNTs) has been studied. Two pairs of cyclic voltammetric peaks corresponding to the two different processes, i.e. mass‐transport and surface reaction of GOD are observed on this MWNTs. The formal potentials with Eo' =‐0.45 V and Eo' =‐0.55 V were obtained respectively. The GOD film was observed on the carbon nanotube by the TEM.
Mineralization of 4‐Chlorophenol under Visible Light Irradiation in the Presence of Aluminum and Zinc Phthalocyaninesulfonates
Authors: Yi‐Ming Xü , Mei‐Qin Hu , Zu‐Xu Chen , Dong‐Yun Zeng 
Published: September 2010

AbstractPhotosensitized oxidation of 4‐chlorophenol (4CP) by the title complexes (AlPcS and ZnPcS) in aerated aqueous solution upon visible light irradiation (δ ≥ 450 nm) has been investigated using methanol as a disassociating reagent. It is confirmed that the monomeric species of the sensitizer is more active than the corresponding dimer in singlet oxygen generation for 4CP oxidation. However, the monomer is also the main component found in the sensitizer's photobleaching. In this regard, AlPcS is much more stable than ZnPcS, and the photobleaching is observed to proceed via singlet and triplet oxygen, respectively. The final products of 4CP oxidation in alkaline solution are carbon dioxide and chloride ions, while at pH = 7 and pH = 3 the p‐benzoquinone is the product. The temperature is found to have influence on both the photosensitized degradation of methyl orange and ZnPcS photobleaching, with an activation energy of 15.8 and 24.2 kJ/mol, respectively.
A Convenient Approach to the Enantiopure (15,25,45,55)‐and (1R,2S,4R,5S)‐2,5‐Bis(phenylmethyl)‐l,4‐diazabicyclo[2.2.2]‐octane
Authors: Li‐Hua Qiu, , Zong‐Xuan Shen, , Wu‐Hong Chen, , Yong Zhang, , Ya‐Wen Zhang, 
Published: September 2010

AbstractCyclodipeptide (3S, 6S)‐bis (phenylmethyl) piperazine‐2,5‐dione was prepared in high yield by heating phenylalanine methyl ester in toluene under reflux. The reduction of this cyclodipeptide with sodium NaBR4‐BF3 in DME gave the (2S, 5S)‐bis(phenylmethyl) piperazine, which, on heating with ethylene bromide and triethylamine, afforded the title compounds. This method was proved to be generally applicable to the synthesis of C2‐symmetric 2, 5‐disubstituted‐1, 4‐diazabicyclo [2. 2. 2] octane from the corresponding natural or unnatural amino add esters.
Silica Hybrid Containing (R)‐2,2′‐Binaphtho‐20‐crown‐6 Moieties via the Sol‐Gel Process
Authors: Yi‐Xiang Cheng, , Tian‐Dong Liu, , Ling‐Wu Chen, 
Published: September 2010

Abstract(R)‐6,6′‐Bis (triethoxysilylethen‐2‐yl)‐2,2′‐binaphtho‐20‐crown6 (precursor, R‐2) derived from (R)‐2,2′‐BINOL derivative was synthesized by Pd‐catalyzed Heck reaction of (R)‐6,6′‐dibromo‐2, 2′‐binaphtho‐20‐crown‐6 (R‐1) intermediate with vinyltriethoxysilane. The hydrolysis and polycondensation of the precursor gave rise to the corresponding xerogel. Both precursor and xerogel were analysed by NMR, FT. IR, UV, CD spectra, fluorescent spectroscopy, polarimetry and elemental analysis. The precursor and xerogel can emit strong blue fluorescence and are expected to have the potential application in the separation of chiral molecules as fluorescent sensor. The precursor exhibits strong Cotton effect in its circular dichroism (CD) spectrum indicating that it is a highly rigid structure.
Heck reaction of iodoarenes with methyl acrylate catalyzed by cyclopalladated complexes of tertiary arylamines immobilized in ionic liquid [Bmim]+BF4−
Authors: Zheng Rui , Yang Fan , Zou Gang , Tang Jie , He Ming‐Yuan 
Published: September 2010

AbstractHeck reaction of iodoarenes with methyl acrylate, catalyzed by cyclopalladated complexes of tertiary arylamines, was investigated in ionic liquid 1‐butyl‐3‐methy Imidazolium tetrafluoroborate ([Bmim] +BF4−). The products can be isolated conveniently from the ionic liquid‐catalyst system. The catalysts could be reused for more than 10 times still with satisfactory catalytic activity.
Conversion of N2O to N2 on MgO (001) surface with vacancy: A DFT study
Authors: Xu Yi‐Jun , Li Jun‐Qian , Zhang Yong‐Fan 
Published: September 2010

AbstractThe adsorption and decomposition of N2O at regular and defect sites of MgO (001) surface have been studied using cluster models embedded in a large array of point charges (PCs) by DFT/B3LYP method. The results indicate that the MgO (001) surface with oxygen vacancies exhibits high catalytic reactivity toward N2O adsorptive‐decomposition. It is different from the regular MgO surface or the surface with magnesium vacancies. Much elongation of O‐N bond of N2O after adsorption at oxygen vacancy site with O end down shows that O‐N bond has been broken with concurrent production of N2, leaving a regular site instead of the original oxygen vacancy site (F center). The MgO (001) surface with magnesium vacancies hardly exhibits catalytic reactivity. It can be concluded that N2O dissociation likely occurs at oxygen vacancy sites of MgO (001) surface, which is consistent with the generally accepted viewpoint in the experiments. The potential energy surface (PES) reflects that the dissociation process of N2O does not virtually need to surmount a given energy barrier.
Exponentially expanded grid network approach (EEGNA): An efficient way for the simulation of stiff electrochemical problems
Authors: Deng Zhao‐Xiang , Lin Xiang‐Qin , Tong Zhong‐Hua 
Published: September 2010

AbstractThe exponentially expanded space grid was incorporated into the network approach to overcome the problem of low simulation efficiency during the simulations of electrochemical problems with stiff kinetics or wide dispersion of diffusion coefficients, resulting in an effective electrochemical simulation method: exponentially expanded grid network approach (EEGNA). The stability and accuracy of the EEGNA for the simulation of various electrode processes coupled with different types of homogeneous reactions were investigated.
Microcalorimetric study of the action of Yb3+ ion on the growth of Staphylococcus aureus
Authors: Hou An‐Xin , Xue Zhi , Liu Yi , Qu Song‐Sheng 
Published: September 2010

AbstractA microcalorimetric method was used to evaluate the action of Yb3+ ions on the growth metabolism of Staphylococcus aureus. The power‐time curves of the growth metabolism of Staphylococcus aureus and the action of Yb3+ ions were obtained by using stopped‐flow method at 37°C. For evaluation of the action, the growth rate constants (k1 and k2) for the log phase 1, log phase 2, and the total heat effect (Qtotal) for Staphylococcus aureus were determined. The results show that Yb3+ ions at low concentrations have the stimulatory effect on Staphylococcus aureus and that Yb* ions at higher concentration could inhibit its growth.
Synthesis, characterization and crystal structure of the first trinuclear MFe2(M = Cu and Ni) complexes based on nitroprusside
Authors: Zhou Bei‐Chuan , Kou Hui‐Zhong , Li Yong , Xiong Ming , Wang Ru‐Ji 
Published: September 2010

AbstractThree new complexes [Ni(H2L)][Fe(CN)5(NO)]2 ± 6H2O (1), [Ni(H2L)][Fe(CN)5(NO)]2 ± 4H2O (2) and [Cu(H2L)][Fe‐(CN)5(NO)]2 ± 4H2O (3) (L = 3,10‐bis(2‐aminoethyl)‐1,3,5, 8,10,12‐hexaazacyclotetradecane) are prepared and characterized by IR, elemental analyses and single‐crystal X‐ray analyses, indicating that they are the first examples of trinuclear nitroprusside‐bridged MFe2 (M = Cu and Ni) complexes. In the three complexes, the central metal atoms (M) are all six‐coordinated by the nitrogen atoms from the macrocyclic ligand and two cyano‐bridges at the trans‐positions to form distorted octahedral configurations. The axial N‐M‐N linkage is nearly vertical to the equatorial plane defined by four coordinating N atoms of macrocyclic ligand. The C ± N‐Ni bond angle of 172.6° in complex 1 is apparently larger than those in complexes 2 and 3 (152.57° and 136.37°, respectively). The three complexes are all connected by hydrogen bonds into 3D networks. This study shows that the cyano‐bridged trinuclear species could be generated via the control of the charge of the building blocks.
Synthesis and structure of the first protonated zincoborophosphate: (H3O)Zn(H2O)2BP2O8·H2O
Authors: Shi Heng‐Zhen , Shan Yong‐Kui , He Ming‐Yuan , Liu Yn‐Yan , Weng Lin‐Hong 
Published: September 2010

AbstractThe solid acid of the first protonated zincoborophosphate, (H3O) Zn (H2O)2BP2O8·H2O (1), was soventothermally synthesized by the reaction of Zn(NO3)2 ± 6H2O and H3BO3 with H3PO4 in a mixed solvent, and structurally characterized by single‐crystal X‐ray diffraction analysis. It crystallizes in the hexagonal P6122, a = 0.9604(4) nm, c = 1.5297(6) nm, V = 1.2218(8) nm3, Dc = 2.921 g/cm3, Z = 6, F (000) = 1080, μ =3.495 mm−1. The structure features that the tetrahedra‐tetrahedra helices interconnected by octahedra and strong hydrogen bond interactions form a three‐dimensional framework. The protonated water molecules are located at unique positions. Other characterizations by IR and thermal analysis are also described.
P NMR studies on the ligand dissociation of trinuclear molybdenum cluster compounds
Authors: Li Zhao‐Ji , Qin Ye‐Yan , Tang Yan‐Hong , Kang Yao , Xia Ji , Chen Zhong , Wu Ling , Yao Yuan‐Gen 
Published: September 2010

AbstractA series of carboxylate‐substituted trinuclear molybdenum cluster compounds formulated as Mo3S4(DTP)3(RCO2)(L), where R = H, CH3, C2H5, CH2Cl, CCl3, R1C6H4(R1 is the group on the benzene ring of aromatic carboxylate), L = pyridine, CH3CN, DMF, have been synthesized by the ligand substitution reaction. The dissociation of the loosely‐coordinated ligand L from the cluster core was studied by 31P NMR. The dissociation process of L is related to the solvent, temperature, and acidity of carboxylate groups, so as to affect the solution structure and reactive properties of the cluster. The long‐distance interaction between ligands RCO2 and L is transported by Mo3S4 core.
Electrochemical polymerization of azure blue II and its electrocatalytic activity toward NADH oxidation
Authors: Li Nian‐Bing , Duan Jian‐Ping , Chen Guo‐Nan 
Published: September 2010

AbstractPoly (azure blue II) (PABII) thin film modified electrode was successfully assembled on the surface of a glassy carbon electrode by means of electrochemical polymerization, which was carried out with cyclic voltammetric sweeping in the potential range of ‐ 0.6 to + 1.3 V (vs. SCE) in Britton‐Robinson buffer solution (pH = 9.8) containing 1.25 ± 10–4 mol/L azure blue II. The effect of pH on the polymerization process of azure blue II and the electrochemical characteristics of the polymer‐modified electrodes were studied in detail. The experimental results indicated that the electropolymerization of azure blue II could take place in basic or neutral media. The cyclic voltammograms of poly (azure blue II) thin film modified electrode showed the presence of two couples of redox peaks. The film modified electrode exhibited potent and persistent electrocatalysis for oxidation of dihydronicotiamide adenine dinucleotide (NADH) in phosphate buffer media with a diminution of the overpotential of about 410 mV and an increase in peak current. The presence of some divalent cations in an electrolyte can greatly enhance the electrocatalytic current for oxidation of NADH. The electrocatalytic current increased linearly with NADH concentration from 1.0 ± 10–5 to 8.0 ± 10–3 mol/L in the presence of 4.0 ± 10–2 mol/L Mg2+ cation. The detection limit (3sb1/S) was 5.0 ± 10–6 mol/L, and the relative standard deviation of determination results was 4.2% for six successive determinations of 5.0 ± 10–4 mol/L NADH in the presence of Mg2+ cation.
Synthesis of cyclohexyl and isopropyl ketones from benzimidazole methiodide salt and grignard reagents
Authors: Yang Bing‐Qin , Qiang Ju‐Li , Bai Yin‐Juan , Lu Jun , Shi Zhen 
Published: September 2010

AbstractThe reaction of 2‐alkyl‐1,3‐dimethylbenzimidazolium salts with Grignard reagents gave addition products which were hydrolyzed to give ketones. A new method for the preparation of cyclohexyl ketones and isopropyl ketones is provided.
Conversion of 3‐carbethoxy‐4‐methyl coumarin derivatives into several new annelated coumarin derivatives
Authors: Mohammed Hadeer Bakeer 
Published: September 2010

AbstractThe reaction of ethyl esters of 4‐methyl‐2‐oxo‐2H‐1‐benzo (naphtho) pyran‐3‐carboxylic acids (1) with aromatic aldehydes in the presence of piperidine yielded 4‐styryl‐3‐carboxamidopiperidyl coumarin derivatives 4. The reaction of hydrazine hydrate with 1 gave acetophenone hydrozone derivatives 5 and acetophenone azine derivatives 6. The reaction of 1 with primary amines afforded compounds 7–9. And the treatment of la with Grignard reagents afforded 3‐aroyl‐4‐methyl coumarin derivatives 10.
Coupling reaction of carbonyl compounds mediated by gallium metal in aqueous media
Authors: Wang Zhi‐Yong , Yuan Shi‐Zhen , Zha Zheng‐Gen , Zhang Zu‐De 
Published: September 2010

AbstractA simple and effective pinacol coupling of various aromatic aldehydes mediated by gallium in good yields has been carried out. The reaction is highly effective in water in the presence of KOH or HCl and was strongly affected by the steric environment surrounding the carbonyl group. Aliphatic aldehydes, ketones and aromatic ketones appear inert under the same reaction conditions.
Contribution to structural elucidation: Behaviours of substructures partially defined from 2D NMR
Authors: Epouhe Celine , Fan Bo‐Tao , Yuan Shen‐Gang , Panaye A. , Doucet J. P. 
Published: September 2010

AbstractStructural elucidation (automatic determination of the structure of a molecule from its spectra) is frequently hampered by combinatorial explosion when trying to assemble the identified substructures. We devised a new method which can avoid this pitfall by a systematic examination of allowed 13C chemical shifts ranges for all substructures chemically possible and combined with a progressive pruning thanks to neighbouring relationships appearing from 2D NMR. This method is explained by a detailed example.