bluuebunny/crossref_metadata_2025 huggingface dataset:
Low‐Valent Titanium Induced Simultaneous Reduction of Nitro Group and SS Bond in Nitrodisulfides: A Facile Synthesis of 2H‐1,4‐Benzothiazines
Authors: Zhang Yong‐Min , Zhong Wei‐Hui , Chen Xiao‐Yian
Published: September 2010

The simultaneous reduction of nitro group and SS bond in nitrodisulfides by TiCl4/Sm system led to the active intermediates 2, which were “living” double‐anions in situ and reacted smoothly with ω‐bromoketones to afford the desired 2/7–1,4‐benzothiazines in good yields under mild and neutral conditions.
Synthesis of New Chiral Calix [4] crown Containing (R)‐Cysteine
Authors: He Yong‐Bing , Xiao Yuan‐Jing , Wu Jin‐Long , Meng Ling‐Zhi , Wu Cheng‐Tai
Published: September 2010

Three new chiral heterocalix [4] crowns containing aza thio atoms bearing two chiral sites provided by (R)‐cysteine ester were synthesized. All new compounds were characterized by 1H NMR, MS and elemental analysis.
Insertion of Dichlorocarbene into CB Bond of Borinates under Liquid‐Liquid Phase Transfer Catalysis Conditions: A Convenient Preparation of Unsymmetrical Ketones
Authors: Huang Shi‐Wen , Guo Feng , Shan Zi‐Xing , Zhao De‐Jie
Published: September 2010

Unsymmetrical ketones were conveniently prepared from the unsymmetrical diorganyl borinates via the insertion of dichlorocarbene into CB bond under liquid‐liquid phase transfer catalysis conditions and oxidation with alkaline hydrogen peroxide in 35–67% yields.
Comparison of Ethene Diffusion Characteristics in H[Al]ZSM‐5 at 300 K and 400 K by Molecular Dynamics
Authors: Fan Jtan‐Fen , Xia Qi‐Ying , Gong Xue‐Dong , Xiao He‐Ming
Published: September 2010

The ethene diffusion characteristics in the framework of H[Al]ZSM‐5 at 300 K and 400 K have been studied by molecular dynamics (MD) simulation. The data have been obtained for the molecular kinetic, potential and total energies, mean square displacement and self‐diffusion coefficient, interaction and beat of adsorption. The dependence of molecular diffusion on temperature has been explored.
Synthesis, Crystal Structure and Third‐order Nonlinear Optical Properties of Nest‐shaped Cluster [CuBr(bpy)2] [MoOS3Cu3‐Br2(bpy)]
Authors: Song Ying‐Lin , Hou Hong‐Wei , Fan Yao‐Ting , Du Chen‐Xia , Zhu Yu
Published: September 2010

Nest‐shaped cluster [CuBr(bpy)2][MoOS3Cu3Br2(bpy)] was synthesized by the treatment of (NH4)2 MOO2S2, CuBr and Et4NBr with bpy (2,2′‐bipyridyl) in CH3CN. Its structure has been characterized by X‐ray diffraction; monoclinic, space group P21/n ‐ with a = l.0092(4), b = 2.6347(7), c = 1.4087(3) nm, β = 91.744(9)°, V = 3.7438 nm3, Z=4, and final R = 0.051, Rw = 0.053. It consists of two parts: nest‐shaped structural unit [MoOS3Cu3Br2(bpy)] and complex ion [CuBr(bpy)2]+. We determined its third‐order nonlinear optical (NLO) properties with a 7‐ns pulsed laser at 532 nm. The duster exhibits strong NLO refractive behavior, its third‐order susceptibility χ(3) was calculated to be 2.7 · 10−11 esu in a 7.8 · 10−4 g/cm3 DMF solution. The value is comparable to those of inorganic dusters.
Design and Synthesis of Novel Peptide Nucleic Acid Monomers
Authors: Bai Jin‐Quan , Li Ying , Liu Ke‐Liang
Published: September 2010

All of the four nucleobases in DNA have replaced the 4‐hydroxy group of N‐[2‐(tert‐butoxycarbonylaminomethyl)‐trans‐4‐hydroxy] tetrahydropyrrole acetic acid methyl ester with cis ‐stereochemistry. An efficient route for the synthesis of N‐[2‐(tert‐butoxycarbonylaminomethyl)‐trans‐4‐hydroxy]‐tetrahydropyrrole acetic acid methyl ester has been developed. Starting with this intermediate, the protected monomers were synthesized by the Mitsunobu reaction or via its tosylate.
Markovnikov Regiocontrol in Hydroboration of Alkene by Trifluoromethyl Substituent
Authors: Fan Yu‐Bo , Wang Quan‐Rui , Ding Zong‐Biao , Tao Feng‐Gang
Published: September 2010

The reaction of dichloroborane BHCl2 with 3,3,3‐trifluoro‐prop‐1‐ene (TFP), and propene have been studied using B3LYP method with 6–31G+ basis set. Based on the calculations, all transition structures have parallelogram‐like H‐B‐C‐C four‐center geometry with small deformations. The introduction of fluorine atoms changes the proportions of hydroborational products and reverses the regioselectivity.
Theoretical Study on Second‐order Nonlinear Optical Properties of Substituted Thiazole Derivatives
Authors: Liu Yong‐Jun , Liu Ying , Zhao Xian , Hu Hai‐Quan , Zhang Dong‐Ju , Liu Cheng‐Bu
Published: September 2010

On the basis of ZINDO program, we have designed a program to calculate the nonlinear second‐order polarizability βyk and βμ according to the SOS expression. The second‐order nonlinear optical properties of 4‐nitro‐4′‐dimethylamino‐stilbene and a series of its thiazole derivatives were studied. The calculated results were that: When replacing a benzene ring in 4‐nitro‐4′‐dimethylamino‐stilbene by a thiazole ring, the influence on β values depends on the position of thiazole ring. When the thiazole ring connects with nitro group (acceptor), the β values increase significantly compared with corresponding stilbene derivatives. The β values of 2‐(p‐donor‐β‐styryl)‐5‐nitro‐thiazole derivatives (2–7) are larger than those of 2‐(p‐nitro‐β‐styryl)‐5‐donor‐thiazole derivatives (8–13) and 2‐(p‐donor‐phenyl)‐azo‐5‐nitro‐thiazole derivatives (14–19). The 2‐(p‐donor‐β‐styryl)‐5‐nitro‐thiazole derivatives (2–7) are good candidates as chromophores duo to their high nonlinearities and potential good thermal stability.
Novel ent ‐Kaurane Diterpenoids from Isodon xerophilus
Authors: Hou Ai‐Jun , Yang Hui , Liu Yan‐Ze , Zhao Qin‐Shi , Lin Zhong‐Wen , Sun Han‐Dong
Published: September 2010

Further investigation on the leaves of Isodon xerophilus afforded three novel ent‐kaurane diterpenoids, xerophilusins D‐F (1–3), together with seven known compounds, phyllostachysin A (4), oleanolic acid, caffeic acid, rosmarinic acid, rutin, quercetin‐3‐O‐β‐D‐glucopyranoside, and quercetin. Structures of 1–3 were elucidated on the basis of their spectral properties and X‐ray crystallographic analysis. Compound 1 showed broad spectra inhibiting human tumor cells and significant cytotoxicity.
Allylation of Diselenides, Aldehydes and Ketones with Ytterbium/Allyl Bromide System
Authors: Su Wei‐Ke , Zhang Yong‐Min , Li Yong‐Shu
Published: September 2010

In the presence of methyliodide, ytterbium can react with allyl bromide smoothly to form allylytterbium bromide, which further reacts with diselenides, aldehydes and ketones to afford allylselenides and homoallylic alcohols respectively in good yields under mild and neutral conditions.
Mechanistic Insights into an Unexpected Carbon Dioxide Insertion Reaction through the Crystal Structures of Carbamic Diphenylthiophosphinic Anhydride and l‐[(4‐Nitrophenyl)‐sulfonyl]‐trans‐2,5‐pyrrolidinedicarboxylic Acid Methyl Ester
Authors: Shi Min , Shen Yu‐Mei , Jiang Jian‐Kang
Published: September 2010

The crystal structures of an unexpected carbon dioxide inserted carbamidiphenylthiophosphinic anhydride and l‐[(4‐nitrophenyl) sulfonyl]‐trans‐2, 5‐pyrrolidinedicarboxylic acid methyl ester were determined by X‐ray analysis. They crystallized in the space group P21(#4) with a =0.9550(2), b = 0.9401(4), c= 1.2880(2) nm, β= 107.74°, V= 1.1013 (5) nm3, Dcaled= 1.349 g/cm3, Z = 2 and P212121(# 19) with a = 1.4666(2), b = 0.7195(2), c = 1.6339(2) nm, V = 1.7240(7) nm3, Dcaled = 1.434 g/cm3, Z = 4, respectively. Through the investigation of these two crystal structures, the mechanistic insights into this unexpected carbon dioxide insertion in the reaction of trans‐2,5‐disubstituted pyrrolidine with diphenylthiophosphoryl chloride in the presence of potassium carbonate were disclosed.
1,3‐Dipolar Cycloaddition of Nitrones with Electron‐rich Alkenes Catalyzed by Yb(OTf)3
Authors: Qian Chang‐Tao , Wang Long‐Cheng , Chen Rui‐Fang
Published: September 2010

1,3‐Dipolar cycloaddition of nitrones with ethyl vinyl ether or 2,3‐dihydrofuran proceeds smoothly in the presence of a catalytic amount (10 mol%) of ytterbium triflate to afford isoxazolidines and dicyclic isoxazolidine respectively with good yields and high stereoselectivity.
Electrostatic Layer‐by‐Layer Assembly of Polycation and DNA Multilayer Films by Real‐time Surface Plasmon Resonance Technique
Authors: Pei Ren‐Jun , Cui Xiao‐Qiang , Yang Xiu‐Rong , Wang Er‐Kang
Published: September 2010

The assembly of alternating DNA and positively charged poly‐(dimethyldiallylammonium chloride) (PDDA) multilayer films by electrostatic layer‐by‐layer adsorption has been studied. Real time surface plasmon resonance (BIAcore) technique was used to characterize and monitor the formation of multilayer films in solution in real time continuously. The results indicate that the uniform multilayer can be obtained on the poly‐(ethylenimine) (PEI) coated substrate surface. The kinetics of the adsorption of DNA on PDDA surface was also studied by real‐time BIAcore technique, and the observed rate constant was calculated using a Langmuir model (kobs = (1.28 ± 0.08) × 10−2s−1).
Studies on Self‐diffusion of Main Components of Hop Oils
Authors: Chen Liu‐Ping , Groβ Thomas , Lüdemann Hans‐Dietrich
Published: September 2010

The self‐diffusion coefficients (D) of α‐humulene and myrcene, which are main components of hop oils, were measured at the temperature range of 274‐372 K and pressures up to 100 MPa by the Stejskal‐Tanner FT NMR method. In order to obtain motional behavior of the molecules in the supercritical conditions, the intradiffusion coefficients (Dü) of the two substances in carbon dioxide were also determined. It was found that the values of Dü are about one order of magnitude higher than that for the pure components at the same‐ranges of temperature and pressure. The self‐diffusion data of α‐humulene and myrcene are analysed, and the diffusion behavior of these compounds is discussed.
Synthesis and Structure of Novel Double Flexible Spacer Bridged Biscalix[4]arenes
Authors: Zeng Xian‐Shun , Weng Lin‐Hong , Chen Lang‐Xing , Ju Hong‐Fang , Leng Xue‐Bing , He Xi‐Wen , Zhang Zheng‐Zhi
Published: September 2010

25, 25′, 27, 27′‐Bis(1,3‐dioxypropane)‐bis(5, 11, 17, 23‐tetra‐tert‐butylcalix[4]arene‐26,28‐diol) (4) and 25, 25′, 27, 27′‐bis(1, 4‐dioxybutane)‐bis (5, 11, 17, 23‐tetra‐tert‐butylcalix‐[4]arene‐26, 28‐diol) (5) were synthesized by the reaction of p‐tert‐butylcalix[4]arene (1) with preorganized 25, 27‐bis(3‐bromoproxyl)calix[4]arene‐26, 27‐diol (2) and 25, 27‐bis(3‐bromobutoxyl)calix[4]arene‐26, 27‐diol (3) in the presence of K2CO3 and KI. Compounds 4 and 5 were characterized with X‐ray analysis and the selectivity of 4 and 5 toward K+ over other alkali metal ions, alkaline metal ions as well as NH4+ were investigated with an ion‐selective electrode.
Calculation of Mass and Abundance for Polyisotopic Ion by Low Resolution Mass Spectrometry
Authors: Yu Chong‐Tian , Guo Yin‐Long , Zhang Zun‐Jian , Xiang Bing‐Ren , An Deng‐Kui
Published: September 2010

The new algorithm calculated mass and abundance for polyisotopic ion by low‐resolution mass spectrometry was developed based on probability theory. The results of mass and abundance data of polyisotopic ion calculated by the algorithm were coincided with the experimental values. By comparison with the Kubinyi's method, our algorithm is simpler and easier to master for operator.
Sardisterol, A New Polyhydroxylated Sterol from the Soft Coral Sarcophyton digitatum Moser
Authors: Su Jing‐Yu , Yang Ruo‐Lin , Zeng Long‐Mei
Published: September 2010

A new polyhydroxylated sterol, named sardisterol, was isolated from the soft coral Sarcophyton digitatum Moser. Its structure was determined as (22R, 24ξ)‐methylcholest‐5‐en‐3β, 22, 25, 28‐tetraol‐3‐acetate on the basis of spectroscopic methods.
A New Synthetic Approach to Coumestan Derivatives
Authors: Gong Deng‐Huang , Li Chao‐Zhong , Yuan Cheng‐Ye
Published: September 2010

A new method for the preparation of coumestan derivatives was described involving an intramolecular palladium‐catalyzed ring closure reaction of coumarins obtained from condensation of substituted o‐hydroxyphenylacetic add and o‐hydroxybenzaldehyde.
A Convenient Synthesis and Molecular Structure of Ru(CO)3[Ph2PN(i‐Bu)PPh2‐P, P]
Authors: Xu Feng‐Bo , Zhang Zheng‐Zhi
Published: September 2010

Ru(CO)3 [Ph2PN (i‐Bu) PPh2‐P, P] was conveniently obtained by the reaction of Ru(DMSO)4Cl2 with Ph2PN(i‐Bu)‐PPb2 and CO in the presence of Zn powder under mild conditions. The crystal and molecular structure was determined by X‐ray diffraction. This compound possesses a distorted trigonal bipyramidal configuration.
Synthesis of Allyl Selenides Promoted by an Sm/ZnCl2 Bimetal System in the Presence of Water
Authors: Zheng Yuri‐Fa , Guo Hong‐Yun , Zhang Yong‐Min
Published: September 2010

The reaction of diselenides with allylic bromides proceeded smoothly in an Sm/ZnCl2 bimetal system in THF‐H2O to afford allyl selenides in good yield.
Engineering Chiral Catalysts through Asymmetric Activation and Super High Throughput Screening (SHTS)
Authors: Mkami Koichi , Korenaga Toshinobu , Matsukawa Satoru , Ding Kui‐Ling , Long Jiang
Published: September 2010

A conceptually new strategy for asymmetric catalysis, namely asymmetric activation, in which a chiral activator selectively activates one enantiomer of a racemic chiral catalyst, and a highly efficient screening system for finding the most effective catalysts, namely super high throughput screening (SHTS), by which the reaction can be conducted in parallel and the ee% of the product is allowed to determine within minutes, are summarized in the present account. It is reasonable to believe that SHTS technique combined with asymmetric activation or deactivation principle will provide a very powerful methodology for finding the new catalysts and the best catalyst tuning for asymmetric reactions.
Theoretical Investigation on the Reactions of H with (CH3)4‐nSiHn (n = 1–4)
Authors: Zhang Qing‐Zhu , Zhang Ji‐Guo , Wang Shao‐Kun , Zhang Miao , Liu Chuan‐Pu , Gu Yue‐Shu
Published: September 2010

The abstractions of H with (CH3)4‐nSiHn (n = 1–4) have been investigated at high levels of ab initio molecule orbital theory. Geometries have been optimized at the MP‐2 level with 6–31G(d) basis set, and G2MP2 level has been used for the final energy calculations. Theoretical analysis provided conclusive evidence that the main process occurring in each case is the abstraction of H from the SiH bond leading to the formation of the H2 and silyl radicals; the abstraction of H from CH bond has higher barrier and is difficult to react in each case. The kinetics of the title reactions have been calculated with variational transition state theory over the temperature range 200–1000 K, and the theoretical rate constants match well with the experimental values.
A New Method to Measure Electroosmotic Flow Mobility of Capillary Electrophoresis by Abrupt Change of Current De‐noising via Wavelet Transform
Authors: Li Qian‐Feng , Zhang Xiao‐Yun , Zhang Hong‐Yi , Chen Xing‐Guo , Liu Man‐Cang , Hu Zhi‐De
Published: September 2010

The electroosmotic flow mobility has been measured by the combination of monitoring the change in electric current during electrophoretic run and operating the wavelet transform. Once the sample solvent zone with different ionic strength from background electrolyte migrated from the capillary, a sudden change in current could be observed from the electric current record of time history. The exact time (in the middle of abrupt range) corresponding to the abrupt change in current was determined by wavelet transform. This work showed that the electroosmotic flow mobility determined by the proposed method was in a good agreement with the neutral marker method commonly used.
Novel Lanthanide Complexes of Ciprofloxacin: Synthesis, Characterization, Crystal Structure and in vitro Antibacterial Activity Studies
Authors: Li Jia‐Bin , Yang Pin , Gao Fei , Han Gao‐Yi , Yu Kai‐Bei
Published: September 2010

Novel lanthanide coordination compounds with ciprofloxacin (CPFX), including eleven complexes Ln(CPFX)2Cl(H2O), (Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb; n = 7, 8, 9) and crystalline [Ce(CPFX)2 (H2O)4] Cl (H2O)3.25 (C2H5‐OH)0.25, were synthesized. The crystal is of triclinic space group Pi with a= 1.3865(2) nm, b = 1.3899(3) nm, c = 1.6505(2) nm, a = 92.73(1)°, β= 114.39(1)°, γ=115.55 (1)°, Z = 2 and R = 0.0449. FT‐IR, electronic spectroscopy and X‐ray diffraction were employed to show that the lanthanide ion, which displays an eight‐coordinate structure, is chelated by 3‐carboxyl and 4‐keto oxygen donors of CPFX and two six‐membered chelate rings are formed. Test of in vitro antibacterial activity against E. coli, P. aeruginosa and S. aureus indicated that the in vitro antibacterial activity of the ligand can be improved by complexation with Ce(III).
Triterpenoid Saponins from Vaccaria segetalis
Authors: Ma Ji , He Fa‐Hu , Deng Jing‐Zhen , Ye Wen‐Cai , Zhao Shou‐Xun , Wu Hou‐Ming
Published: September 2010

Four novel triterpenoid saponins, Vaccariside B‐E (1–4), were isolated from the seeds of Vaccaria segetalis and their structures were elucidated as 3‐O‐β‐D‐galactopyranosyl‐(1–2)‐β‐D‐glucuronopyranosyl quillaic add 28‐O‐β‐D‐xylopyranosyl‐(1–3)‐α‐L rhamno‐pyranosyl‐(1–2)‐[α‐L‐arabinofura‐nosyl‐(1–3)]‐4‐O‐acetyl‐β‐D)‐fucopyranoside (1), 3‐O‐β‐D‐galactopyranosyl ‐ (1–2) −3‐O‐acetyl‐β‐D ‐ glucuronopyranosyl quillaic acid 28‐O‐β‐D‐xylopyranosyl‐(1–3)‐α‐L‐rhamnopyra‐nosyl‐(1–2)‐[α‐L‐arabinofuranosyl‐(1–3)]‐4‐O‐acetyl‐β‐D‐fucopyranoside (2), 3‐O‐β‐D‐galactopyranosyl‐(1–2)‐β‐D‐glucuronopyranosyl quillaic add 28‐O‐α‐L‐arabinopyranosyl‐(1–3)‐α‐L‐rhamnopyranosyl‐(1–2)‐[α‐L‐arabinofuranosyl‐(1–3)]‐4‐O‐acetyl‐β‐D‐fucopyranoside (3), 3‐O‐β‐D‐galacto‐pyranosyl‐(1–2)‐[β‐D‐xytopyranosyl‐(1–3)]‐β‐D‐glucurono‐pyranosyl quillaic add 28‐O‐β‐D‐xylopyranosyl‐(1–3)‐α‐L‐rhamnopyranosyl‐(1–2)‐[α‐L‐arabinofuranosyl‐(1–3)]‐4‐O‐acetyl‐β‐D‐fucopyranoside (4), respectively.
Electrochemical Polymerization of Methylene Green
Authors: Zhu Hong‐Ping , Mu Shao‐Lin
Published: September 2010

The electrochemical polymerization of methylene green has been carried out using cyclic voltammetry. The electrolytic solution consisted of 4° 10−3 mol/L methylene green, 0.1 mol/L NaNO3 and 1 × 10−2 mol/L sodium tetraborate with pH 11.0. The temperature for polymerization is controlled at 60°C. The scan potential is set between −0.2 and 1.2 V (vs. Ag/AgCl with saturated KCl solution). There are an anodic peak and a cathodic peak on the cyclic voltammogram of poly (methylene green) at pH≤3.8. Both peak potentials shift towards negative potentials with increasing pH value, and their peak currents decrease with increasing pH value. Poly (methylene green) has a good electrochemical activity and stability in aqueous solutions with pH≤3.8. The UV‐Visible spectrum and FTIR spectrum of poly (methylene green) are different from those of methylene green.
Chiral Camphor Derivatives as New Catalysts for Asymmetric Phase‐Transfer Alkylation
Authors: Zhang Jie , Wu Xin‐Yan , Zhou Qi‐Lin , Sun Jie
Published: September 2010

The synthesis of new chiral phase‐transfer catalysts based on the optical camphor is described. The alkylation of the benzophenone imine of glycine tert‐butyl ester with benzyl bromide in the presence of new chiral phase‐transfer catalysts afforded the desired alkylation product in good yields and up to 39% ee.
Novel Bonding Character of the Cyclic AlS2 and GaS2 Systems
Authors: Song Xin‐Yu , Nie Yi , Bu Yu‐Xiang
Published: September 2010

The geometries, the harmonic vibrational frequencies and the bonding properties have been predicted for cyclic AlS2 and GaS2 species at the density functional theory (DFT), MPn (n = 2, 3, 4), QCISD(T) and CCSD(T) levels with 6‐311 + G (2df) basis set. The novel bonding character was discussed.
Effect of Substituents on Aggregation Behaviors of Stilbazole and Stilbazolium Derivatives
Authors: Yang Wen‐Sheng , Jiang Yue‐Shun , Wang De‐Jun , Li Tie‐Jin
Published: September 2010

Stilbazole and stilbazolium derivatives with dialkylaniline as electron pushing substituents and pyridine or pyridinium substituents as electron drawing substituents were synthesized and their aggregation behaviors were studied by UV‐visible, fluorescence and surface photovoltage spectroscopies. Experimental results indicate that the formation of aggregates can be mediated by the electron drawing ability of the substituents introduced for those compounds all bearing strong electron pushing substituent. When the electron drawing substituent is pyridine group, the molecules tend to aggregate in head‐to‐tail manner, whereas the substituent is pyridinium group, the molecules tend to aggregate in face‐to‐face manner. The effect of electron pushing and drawing ability of the substituents on the aggregation behavior is further analyzed in terms of frontier orbital interactions.
Interactions of Safranin T with Nucleic Acids
Authors: Wang Zhen‐Xin , Liu Dian‐Jun , Dong Shao‐Jun
Published: September 2010

The interactions of Safranin T (ST) with several nucleic acids have been investigated by electrochemical, UV‐visible and CD spectroscopic techniques. The form of the nucleic acid‐ST complexes is sensitive to the ratio of the two species. Two electrochemically inactive complexes such as, nucleic acid‐ST and nucleic acid‐2ST, were formed while ST interacts with nucleic acids. Two processes were obtained from spectral experiments: (1) at the high value of R (R is defined as the ratio of the total concentration of ST to that of nucleic acid), ST is groove‐binding with stacking, (2) at the low value of R, ST is groove‐binding without stacking. Intrinsic binding constants were obtained by spectral methods. The experiments also show that electrostatic binding plays an important role in the interaction of ST with nucleic acids.
Determination of Dissociation Constants of Complicated Compounds by Capillary Zone Electrophoresis
Authors: Liu Hai‐Xing , Yang Geng‐Liang , Wang De‐Xian , Sun Su‐Fang , Ma Jian‐Jun
Published: September 2010

In this work, the whole theoretical methods for the determination of pKa1. and pKa2. of complicated compounds are proposed by capillary zone electrophoresis. The pKa values are achieved by non‐linear regression analysis by taking into consideration the effect of activity coefficient. This is the first report on determining the dissociation constants of gastrodin, magnolol, honokiol, quercetin, curcumin, diethylstilbestrol, 4‐acetamidophenol, eugenol and paeonol.
Structure and Photochemical Properties of r‐1, c‐2, t‐3, t‐4‐l, 3‐Bis [2‐ (5‐R‐benzoxazolyl) ] −2,4‐di (4‐R' ‐phenyl) cyclobutane
Authors: Zhang Wen‐Qin , Zhuang Jun‐Peng , Li Chun‐Bao , Sun Hao , Yuan Xue‐Ning
Published: September 2010

r‐1, c‐2, t‐3, t‐4‐1,3‐Bis[2‐(5‐R‐benzoxazolyl)]‐2,4‐di(4‐R'‐phenyl)cyclobutane (IIa: R=R' = H; IIb: R=Me, R'= H; IIc: R = Me, R' = OMe) was synthesized with high stereo‐selectivity by the photodimerization of trans‐l‐[2‐(5‐R‐benzoxazolyl)]‐2‐(4‐R'‐phenyl) ethene (Ia: R=R' = H; Ib: R = Me, R' = H; Ic: R = Me, R' = OMe) in sulfuric acid. The structures of IIa–IIc were identified by elemental analysis, IR, UV, 1H NMR, 13C NMR and MS. The molecular and crystal structure of IIc has been determined by X‐ray diffraction method. The crystal of IIc (C34H30N2O4. 0.5C2OH) is monoclinic, space group P21/n with cell dimensions of a = 1.5416(3), b =0.5625(1), c = 1.7875(4) nm, β = 91.56 (3)°, V= 1.550(1) nm3, Z = 2. The structure shows that the molecule of IIc is centrosymmetric, which indicates that the dimerization process is a head‐to‐tail fashion. The selectivity of the photodimerization of Ia–Ic has been enhanced by using acidic solvent and the reaction speed would be decreased when electron donating group was introduced in the 4‐position of the phenyl group. That the photodimerization is not affected by the presence of oxygen as well as its high stereo‐selectivity demonstrated that the reaction proceeded through an excited singlet state. It was also found that under irradiation of short wavelength UV, these dimers underwent photolysis completely to reproduce its trans‐monomers, and then the new formed species changed into their cis‐isomers through trans‐cis isomerization.
Slowing Down in Chemical Tristability Systems
Authors: Zhan Ye‐Hong , Zhang Chun‐Hua , Wu Fu‐Gen , Hu Yi‐Hua
Published: September 2010

In this paper two kinds of slowing down in the chemical tristability systems are studied. One is the critical slowing down at the edges of tristable region, and the other is the slowing down far from the critical point, which has much to do with the unstable steady‐points. The results possess some universal properties.
Theoretical Study of the Unimolecular Decomposition Mechanism of Chloromethanol
Authors: Wang Shao‐Kun , Zhang Qing‐Zhu , Hou Hua , Wang Bin , Liu Fu‐Xiang , Gu Yue‐Shu
Published: September 2010

The decomposition pathways of chloromethanol have been studied by ab initio calculation. Equilibriums and transition states have been optimized at the UMP2(full)/6–31G(d) level. The single point energies have been obtained at higher level of G3 (MP2). Four transition states and eight reaction pathways have been revealed and the most favorable reaction to decomposition pathway is the 1, 2‐HCI elimination, which is consistent with the former scientist's conclusion.
Hydrophobically Modified Polyelectrolytes: V. Interaction of Fluorocarbon Modified Poly (acrylic acid) with Various Added Surfactants
Authors: Zhou Hui , Song Guo‐Qiang , Guo Jin‐Feng , Zhang Yun‐Xiang , Dieing Reinhold , Ma Lian , Haeussling Lukas
Published: September 2010

The interactions between fluorocarbon‐modified poly (sodium acrylate) and various kinds of added surfactants have been studied by means of viscometric measurement. Association behavior was found in both hydrogenated and fluorinated anionic, nonionic and cationic surfactants. Among them, the interactions between fluorocarbon‐modified poly (sodium acrylate) and cationic surfactants are the strongest, owing to the cooperation of both electrostatic attractions and hydrophobic associations. The anionic surfactants have the weakest effects on the solution properties because of the existence of unfavorable electrostatic repulsion. The hydrophobic interactions between copolymers and fluorinated surfactants are much stronger than those between copolymers and hydrogenated surfactants.
MEDV‐13 for QSAR Studies on the COX‐2 Inhibition by Indomethacin Amides and Esters
Authors: Liu Shu‐Shen , Yin Chun‐Sheng , Shi Yun‐Yu , Cai Shao‐Xi , Li Zhi‐Liang
Published: September 2010

A molecular electronegativity distance vector based on 13 atomic types (MEDV‐13), is a descriptor for predicting the biological activities of molecules based on the quantitative structure‐activity relationship (QSAR). The MEDV‐13 with 91 descriptors is employed to describe the structures of a series of selective cyclooxygenase‐2 (COX‐2) inhibitors including 16 indomethacin and its amide and ester derivatives (ImAE). A principal component regression (PCR) is used to derive a QSAR model relating the biological activities expressed by p/C50 values to the MEDV‐13. With the number of principal components of 6, the correlation coefficient (R) and the root mean square error (RMS) are 0.9245 and 0.1682 in modeling stage, and 0.8417 and 0.2389 in leave‐one‐out prediction step, respectively.
Electrospray Mass Spectrometry Study on Polynuclear Pd(II) and Ni (II) Complexes of 3, 6, 9, 16, 19, 22‐Hexaazatricyclo [22. 2.2.211,14] triaconta‐11, 13, 24, 26 (1), 27, 29‐Hexaene
Authors: He Wei‐Jiang , Liu Fang , Ye Zhi‐Feng , Mei Yu‐Hua , Guo Zi‐Jian , Zhu Long‐Gen
Published: September 2010

Polynuclear Pd(II) and Ni(II) complexes of macrocyclic polyamine 3,6,9,16,19,22‐hexaazatricyclo[22.2.2.211,14]‐triaconta 11,13,24,26(l),27,29‐hexaene (L) in solution were investigated by electrospray ionization mass spectrometry (ESIMS). For methanol solution of complexes M2LX4 (M = Pd(II) and Ni(II), X= Cl and I), two main clusters of peaks were observed which can be assigned to [M2LX3]+ and [M2LX2]2+. When Pd2LCl4 was treated with 2 or 4 mol of AgNO3, it gave rise formation of Pd2LCl2 (NO3)2 · H2O and [Pd2L(H2O)m(NO3)n](4‐n)+, respectively. ESMS spectra show that the dissociation of the former in the ionization process gave peaks of [Pd2LCl2]2+ and [(Pd2LCl2)NO3]+, while dissociation of the later gave the peaks of [Pd2L(CH3CO2)2]2+ and [Pd2L(CH3CO2)2](NO3) + in the presence of acetic acid. Similar species were observed for Pd2LI4 when treated with 4 mol of AgNO3. When [Pd2L · (H2O)m(NO3)n](4‐n)+ reacted with 2 mol of oxalate anions at 40°C, [Pd4L2(C2O4)2(NO3)2]2+ and [Pd4L2(C2O4)2 (NO3)]3+ were detected. This implies the formation of square‐planar molecular box Pd4L2(C2O4)2(NO3)4 in which C2O4− may act as bridging ligands as confirmed by crystal structure analysis. The dissociation form and the stability of complex cations in gaseous state are also discussed. This work provides an excellent example of the usefulness of ESIMS in the identification of metal complexes in solution.
Crystal Structure and Luminescence of [Eu(TTA)3·DAF]·0.5C7H8 Complex Excited by Visible Light
Authors: Liu Hul‐Biao , Li Bao‐Long , Wang Hua‐Qin , Xu Zheng
Published: September 2010

The non‐ionic europium(III) complex [Eu(TTA)3·DAF]·0.5C7H8 (TTA = 2‐thenoytrifluoroacetonate, DAF = 4, 5‐diazafluoren‐9‐one) was synthesized. The structural determination has been carried out. DAF coordination induces the both excitation spectra in the solid state and solution having a red shift and sensitizes Eu3+ luminescence under visible light excitation.
A New Dinuclear Copper (II) Complex of a Bis‐macrocyclic Ligand: Synthesis, Characterization, Crystal Structure and Magnetic Properties
Authors: Du Miao , Xu Qiang , Guo Ya‐Mei , Weng Lin‐Hong , Bu Xian‐He
Published: September 2010

A new dinuclear Cu(II) complex, [Cu2L(N3)2](ClO4)1.5 (OH)4.5 · 2H2O 0.5C2H5OH (1), of a bis‐macrocyclic ligand, 2,6‐bis(l,4,7,10‐tetraazacyclododecan‐10‐ylmethyl)‐methoxybenzene (L), has been synthesized, characterized and structurally determined by X‐ray diffraction analysis. Complex 1 crystallizes in orthorhombic crystal system, Pca2(l) space group with a = 1.5371(3), b = 1.6641(3), c = 3.0950(6) nm, V = 7.917(3) nm3, Fw = 904.62, Z=8, Dc= 1.529 g/cm3 and final R = 0.0568, wR = 0.1406 for 10410 observed reflections with I≥2σ (I). Both Cu(II) centers in the structure are coordinated by four nitrogen atoms of 1,4,7, 10‐tetraazacyclododecane (cyclen) and a nitrogen donor of the axial azide anion. Each Cu(II) center is in a square‐pyramidal coordination environment, and the intra‐and nearest inter‐molecular CuCu nonbonding distances are 0.9855 and 0.7298 nm, respectively. Variable temperature magnetic susceptibility measurements in the range of 4.2–300 K indicate mat there exists weak intra‐ and inter‐molecular antiferromagnetic coupling between the Cu(II) centers with 27= −4.2 cm−1 and Θ = −0.47 K.
Synthesis and Properties of Triphenylgermanium Heteroaromatic Carboxylates and Crystal Structure of Triphenylgermanium 2‐Furoate
Authors: Yin Han‐Dong , Wang Chuan‐Hua , Wang Yong , Zhang Ru‐Fen , Ma Chun‐Lin , Tao Xu‐Quan
Published: September 2010

Ten triphenylgermanium heteroaromatic carboxylates Ph3GeO2CR (where R=2‐furanyl, 2‐furanvinyl, 2‐(5‐tertbutyl) furanyl, 2‐thiophenyl, 2‐pyridinyl, 3‐pyridinyl, 4‐pyridinyl, 3‐indolyl, 3‐indolylmethyl, 3‐indolylpropyl) were synthesized by the reaction of sodium heteroaromatic carboxylates with the triphenylgermanium chloride. All compounds were characterized by elemental analysis, 1H NMR and MS spectra. The compounds were tested against two human tumour cell lines: MCF‐7 and WiDr. The results showed that they had high activities. The crystal structure of triphenylgermanium 2‐furoate was determined by X‐ray single crystal diffraction. The crystal belongs to monoclinic with space group P21/c, a = 1.1545(4), b=0.9934(3), c = 1.6284(5) nm, β= 91.59(5), Z = 4. In this crystal, the structure consists of discrete molecule containing four‐coordinate germanium atom in a distored tetrahedron.
Synthesis of Novel Chiral Biphenylamine Ligand 6,6'‐Dimethoxy‐2,2′‐diaminobiphenyl
Authors: Chen Yi‐Xin , Li Yue‐Ming , Lam Kim‐Hung , Chan Altera S. C.
Published: September 2010

A new chiral ligand 6,6′‐dimethoxy‐2,2′‐diaminobiphenyl was successfully prepared from 3‐nitrophenol via iodination, Ullmann coupling, and reduction. The resolving reagent (2R, 3R)‐ or (2S,3S)‐2,3‐di (phenylaminocarbonyl)tartaric acid was prepared from commercially available tartaric acid in large scale and was used to resolve the racemic 6,6′‐dimethoxy‐2,2′‐diaminobiphenyl. The chiral 6,6′‐ dimethoxy‐2,2′‐diaminobiphenyl obtained was proved to be enantiomerically pure.
Microwave Induced Synthesis of 3‐Aryl‐6‐(6‐/8‐substituted 4‐chloroquinoline‐3‐yl) ‐ s ‐triazolo [3,4‐b] −1,3,4‐thiadiazoles
Authors: Qiao Ren‐Zhong , Hui Xta‐Ptag , Xu Peng‐Fei , Zhang Zi‐Yi , Cheng Dong‐Liang
Published: September 2010

The condensation of 4‐amino‐3‐aryl‐5‐mercapto‐1, 2, 4‐triazoles (1a‐f) with 6‐/8‐substituted 1,4‐dihydro‐4‐oxo‐quinoline‐3‐carboxylic adds (2a‐d) in the presence of phosphorus oxychloride on refluxng or under microwave irradiation gave twenty four novel 3‐aryl‐6‐ (6‐/8‐substituted 4‐chloroquinoline‐3‐yl)‐s‐triazolo[3,4‐b]‐1, 3,4‐thiadiazoles (4a‐x), Considerable increase in the reaction rate has been observed with improved yields under microwave irradiation. The structures of the compounds synthesized were determined by elemental analyses, IR, 1H NMR and MS spectra. Their spectral properties and the reaction mechanism were also discussed. The preliminary biological test showed that some of compounds bad moderate antibacterial activities.
Preparation and Stabilization of Emulsifier‐free Macromolecule Nanoparticle Latex Particles
Authors: You U‐Sha , Wu Hua‐Qiang , Zhang Wen‐Min , Fu Zhong , Shen Liang‐Jun
Published: September 2010

By using acetone‐water as the medium and potassium persulfate (KFS) as the initiator, emulsifier‐free emulsion co‐polymerization of styrene with co‐monomers: MMA, BMA, EA and BDA under microwave irradiation has been investigated. The influence of the each co‐monomer content and hydrophilicity on the hydrodynamic radius Rh of the synthesized copolymer nanoparticles is discussed in detail. The results show mat the increase in ratio of hydrophilic copolymer causes an increase in consumption of the initiator in the initiation reaction, so an increase in the concentration of the surface OSO3 groups which cause the increase in the stability of the latex and gives rise to the formation of smaller micelles. The nano‐particle radius will increase again when the co‐monomer content increases to a certain degree. The curve of the particle hydrodynamic radius vs the co‐monomer content has a minimum point.
Synthesis and Photophysical Properties of C60‐carbazole Adducts
Authors: Yin Gui , Mao Xin‐Ping , Suo Zhi‐Yong , Xu Zheng
Published: September 2010

Three C60‐carbazole adducts have been synthesized by 1, 3‐dipolar cycloaddition reaction. Intramolecular energy/electron transfer from carbazole to C60 was observed by steady‐state absorption and fluorescence spectra. The fluorescence spectra of these adducts were similar to each other and dependent on the excitation wavelength and solvent.
Studies on the Mechanism for the Bimolecular Metathesis Reaction CH3 + HCI ⇔︁ CH4 + CI
Authors: Zhou Zheng‐Yu , Chen Guang , Zhou Xin‐Ming , Fu Hui
Published: September 2010

The geometry optimization of the transition state, the precursor complex and the successor complex was performed at the 6–311G* basis set level. From the analysis of the vibrational frequency of the precursor complex, transition state, successor complex and the isolated state, the reaction mechanism was derived which was complicated with the bond‐rupture electron transfer theory. The atom H in molecule HCI attacks the atom C, forming a transition state via the precursor complex and the electron‐transfer happens in precursor complex. And the active energy, electronic coupling matrix element, the reorganization energy, and the reaction rate are obtained.
Simultaneous Determination of Vitamin B Complex Using Wavelet Neural Network
Authors: Yin Chun‐Sheng , Guo Wei‐Min , Liu Shu‐Shen , Shen Yang , Pan Zhong‐Xiao , Wang Lian‐Sheng
Published: September 2010

A simultaneous determination of four components of B‐group vitamin, using a novel wavelet‐based neural network (WNN), combined with correlation coefficient and standard deviation approach for wavelength selection, was reported in this work. Eleven representative wavelength points were selected from each original UV spectrum, based on correlation coefficients and standard deviations of the observed data. A family of wavelet basic functions built from Morlet wavelet was adopted to improve the transfer quality of output data and solve the problems of training difficultly involved in neural networks. The predicted results, with fitting correlation coefficients (R = 0.9998–0.9999) and rooted mean squares errors (RMS = 0.0578–0.1478), are satisfactory.
Crystal Structure and Spectroscopic Studies of Bis (morpholine dithiocarbamate) Nickel(II) Complex, Ni(C4H8ONCS2)2
Authors: Pan Su , Wang Ying
Published: September 2010

The title compound has been prepared and characterized by EA, IR and TG spectral studies. The crystal structure of nickel (H) bis(morpholine dithiocarbamate) Ni(C4H5ONC‐S2)2 is determined by X‐ray diffraction methods. It crystallizes in the monoclinic system, space group P21/n, with lattice parameters a = 0.4288(1), b = 2.0526(4), c = 0.8333 (2) nm, β = 97.43(3)°, and Z = 2. In the structure, central Ni atom coordination geometry is slightly distorted square‐planar with the four S atoms from two morpholine dithiocarbamate ligands. The four NiS bond distances are in the range of 0.2199(5)–0.2201(2) nm. The ER spectral data are in agreement with the structural ones. The TG data indicate that it decomposed completely at the 766.89°C.
Formation and Molecular Structure of an Ion Pair Iron (II) Compound Derived from 2,6‐Bis‐ [1‐(2,6‐dibromophenylimino) ‐ethyl] pyridine and 2‐Acetyl‐6‐[1‐(2, 6‐dibromophenylimino)‐ethyl] pyridine
Authors: Chen Rui‐Fang , Qian Chang‐Tao , Sun Jie
Published: September 2010

Two novel tridentate ligands of 2,6‐bis‐[l‐(2,6‐dibromophenylimino) ethyl] pyridine (L1) and2‐acetyl‐6‐[1‐(2,6‐dibromophenylimino) ethyl] pyridine (L2) have been synthesized. The iron(II) complex of L1 and L2 has been characterized with the crystal structure of [Fe(L1)(L2)]2+ [FeCl4]2 CH2Cl2 [monoclinic, P21 (#11), a = 1.0562(4), b = 2.0928(4), c = 1.2914(2) nm, β = 100.12°, V = 2.810(1) nm3 Dc = 1.879 g/cm3 and Z = 2].
Liquid Crystalline Thiadiazole Derivatives: Thiadiazole Derivatives Containing Pyridine Ring as Terminal Group
Authors: Xu Yan , Zhu Zhi‐Guo , Xu Zheng
Published: September 2010

The synthesis and mesomorphic behavior of a new series of liquid crystals containing 1, 3, 4‐thiadiazole and pyridine rings with ‐CH = N‐ central group are reported. All compounds exhibit enantiotropic smectic A mesophase, but the Schiff's base analogues have no mesomorphic behavior. The influence of the pyridine ring and thiadiazole ring is discussed.
Atom Transfer Radical Polymerization of Styrene Using a Bifunctional Initiator
Authors: Yuan Jin‐Ying , Zheng Quan , Tao Lei , Pan Cai‐Yuan
Published: September 2010

A bifunctional alkyl halide, namely l, 2‐bis(2′‐bromobutyryl) ethane (BBrBE), was synthesized and used to initiate the bulk atom transfer radical polymerization (ATRP) of styrene (St) at 110°C in the presence of CuBr/2,2′‐bipyridyl. The narrow polydispersity of polystyrene (PSt) with precisely two arms could be synthesized. The initiate ability of the two active bromide functional groups at both sides of BBrBE for St and the propagation ability of the two arms were confirmed to be similar by the characterization of the individual arms obtained upon hydrolysis of the ester link between the core and the branches.
Glycosides from the Leaves of Ilex latifolia
Authors: Ouyang Ming‐An
Published: September 2010

Nine new triterpenoid saponins; latifolosides IQ and three known compounds: Kudinoside A, cis‐roseoside, and kaempferol‐3‐O‐α‐L‐rhamnopyranosyl (1–6)‐O‐β‐D‐glucopyanoside were isolated from the leaves of Ilex latifolia. Their structures were elucidated by spectroscopic and chemical methods.
Reductive Coupling Reaction of Aryliminomethylferrocenes with Triethyl Orthoformate Induced by Low‐valent Titanium
Authors: Gong Jun‐Fang , Wu Yang‐Jie , Gui Xiu‐Ling , Du Chen‐Xia , Zhu Yu
Published: September 2010

Reductive coupling reaction of aryliminomethylferrocenes FcCH = NAr[(1, Ar=QHs (a), p‐ClC6H4 (b), p‐BrC6H4 (c), p‐CH3C6H4 (d), m‐ClC6H4 (e)] with triethyl orthoformate (2) in Zn‐TiCl4 system gave three kinds of products: 1, 3‐diaryl‐4, 5‐diferrocenyl imidazolidines (3), N, N‐disubstituted formamides (4), and 1, 2‐diferrocenyl ethylene (5). 1H NMR spectra proved that all the compounds 3 obtained were dl‐isomers. All the new compounds 3 and 4 were characterized by elemental analysis, 1H NMR, 13C NMR (for 3) and IR spectra. The molecular structure of 3c was determined by X‐ray diffraction.
Crystal Structure and Electrospray Mass Spectrum of Tris(2, 5‐dioxopyrrolidin‐1‐ylmethyl) amine
Authors: Zheng Hang‐Jun , Jin Lin‐Pei , Guo Jian‐Quan , Zhuang Jin‐You , Zhu Long‐Gen , Mei Yu‐Hua
Published: September 2010

A novel N‐Mannich base tris(2, 5‐dioxopyrrolidin‐1‐ylmethyl)‐amine (TDOPMA) was synthesized and its structure was determined by single crystal X‐ray diffraction. Unlike NH3 molecule, three C‐N‐C bond angles containing the central N atom in the tide compound are unequal and about 9° larger than H‐N‐H angles of NH3 molecule. Electrospray ionization (ESI) mass spectrometry was applied to the title compound. Its fragments were interpreted and possible fragmentation mechanism was given.
Stereoselective Synthesis of (E)‐Cinnamates with Sm/HOAc
Authors: Fan Xue‐Sen , Zhang Yong‐Min
Published: September 2010

The reductive desulfonylation of α‐phenylsulfonylcinnamates promoted by Sm/HOAc led to the corresponding (E)‐cinnamates stereoselectively in good yields under mild conditions.
In situ monitoring of the rising of aqueous solution meniscus for a partially immersed silver electrode during electrochemical reduction of oxygen
Authors: Xie Qing‐Ji , Zhang You‐Yu , Guo Yang‐Hui , Su Xiao‐Li , Li Yun‐Long , Yao Shou‐Zhuo
Published: September 2010

Rising phenomena of aqueous solution meniscus were found for the silver electrode of a 5 MHz piezoelectric quartz crystal (PQC) partially immersed in Na2SO4, NaClO4, HClO4 and NaF aqueous solutions at oxygen reduction potentials, respectively. A detailed study revealed that a decrease in contact‐angle hysteresis (or a contact‐angle decrease) and a continued collection of the water product at the solid‐gas‐solution interface during oxygen reduction, rather than the electrocapillary effect and an agitation effect induced by the oscillation of PQC, are responsible for the meniscus‐rising phenomena. In addition, in situ determination of the immersed height of a partially immersed Ag electrode was studied on the basis of simultaneous measurements of the electroacoustic admittance and electrochemical impedance.
Electrochemical study on interaction of vincristine with tubulin
Authors: Yu Yong , Li Qi‐Long
Published: September 2010

In Tris (0.005 mol/L)‐NaCl (0.05 mol/L) buffer solution (pH = 7.10), keeping temperature at 37°C, a highly sensitive reduction peak of the antitumor agent was obtained by linear sweep voltammetry. The peak potential is‐1.56 V (vs. SCE). The peak current is proportional to the concentration of vincristine over the range of 2.1 ± 10−7‐4.2 ± 10−6 mol/L with the detection limit of 1.0 ± 10−7 mol/L. The behavior of the binding of vincristine to tubulin was studied. The results showed that the reaction of tubulin dimer with vincristine formed an electrochemically active complex to be 1:2. Its stability constant is 2.5 ± 1014. The reduction process of the complex is irreversible with adsorptive characteristics.
Preparation and properties of vesicles from condensable amphiphilic amino acids
Authors: Xiong Xiang‐Yuan , He Wei , Li Zi‐Chen , Li Fu‐Mian
Published: September 2010

Three double‐chain amphiphiles with amino acid groups as hydrophilic moiety were synthesized. These amphiphiles can be easily dispersed in buffer solution to form transparent dispersion. Examination of the dispersion by transmission electron microscopy (TEM) showed the formation of stable vesicular aggregates, which was also confirmed by the ability to encapsulate water‐soluble dyes. Since amino acid groups are located on the surface of the vesicles, water‐soluble carbodiimide can induce the condensation of these groups to form peptide. The phase transition temperatures of these vesicles were estimated by differential scanning calorimetry (DSC), and a decrease of phase transition temperature was observed after polycondensation due to the disturbance of the ordered arrangement of the hydrophobic chains. The leakage rate of the vesicles before and after condensation was studied by monitoring the increase of fluorescence intensity of water‐soluble dye. These vesicles belong to the least permeable ones and the leakage rate can be controlled by varying the degree of condensation or the temperature.
Synthesis, structure and antitumor activity of dibutyltin oxide complex with 5‐fluorouracil derivatives
Authors: Zuo Dai‐Shu , Jiang Tao , Guan Hua‐Shi , Qi Xin , Wang Kui‐Qi , Shi Zhan
Published: September 2010

The dibutyltin(IV) oxide complex reacts with 5‐fluorouracil‐l‐propanonic or5‐fluorouracil‐1‐acetic acid to give the potential antitumor activity complexes [(5‐fluorouracil)‐1‐(CH2)mCOOSn(Bu‐n)2]4O2[m = 1, (1); m = 2, (2)] which were determined by IR and 1H NMR. The crystal structure determination shows that complex 2 is a dimmer, in which two [(5‐fluorouracil)‐1‐CH2CH2COOSn(Bu‐n)2]2O units are linked by bridging oxygen atom, and the tin atoms adopt distorted trigonal bipyramids via two carbons from dibutyl group and three oxygen atoms from 5‐fluorouracil and bridging oxygen. In vitro test shows complexes 1 and 2 exhibit high cytotoxicity against OVCAR‐3 and PC‐14.
Two new dialkoxy‐substituted nido‐platinaundecaboranes: [(PPh3)2PtB10H10‐8,10–2(OCH2CH3)] ± CH2Cl2(I), { (PPh3)2‐PtB10H10‐8,10–2[OCH(CH3)2]} (II)
Authors: Yong Wei , Hu Chun‐Hua , Dou Jian‐Min , Sun Jie , Hu Ke‐Ji , Jin Ruo Shui , Zheng Pei‐Ju
Published: September 2010

Two title nido‐11‐vertex platinaundecaboranes, 7,7‐bis‐(triphenylphosphine‐P)‐8, 10‐diethoxy‐8, 9:10, 11‐bis‐μ‐H‐7‐platina‐nido‐undecaborane‐dichloromethane (I) and 7,7‐bis‐(triphenylphosphine‐P) ‐8, 10‐di(i‐propoxy) ‐8,9:10,11‐bis‐μ‐H‐7‐platina‐nido‐undecaborane (II), were prepared and their structures were determined by single crystal X‐ray diffraction method. Each of them has an 11‐vertex nido‐polyhedral skeleton. {PtB10} cage is substituted by two ethoxy or i‐propoxy groups at 8 and 10 positions, respectively.
Ab Initio calculation of 19F NMR chemical shielding for alkaline‐earth‐metal fluorides
Authors: Cai Shu‐Hui , Chen Ztang , Lu Xin , Chen Zw‐Wei , Wan Hui‐Lin
Published: September 2010

Gauge‐independent atomic orbital (GIAO) method at Hartree‐Fock (HF) and density functional theory (DFT) levels, respectively, was employed to calculate 19F NMR chemical shieldings of solid state alkaline‐earth‐metal fluorides MF2 (M = Mg, Ca, Sr, Ba). The results show that, although the calculated 19F chemical shieldings tend to be larger than the experimental values, they have a fairly good linear relationship with the observed ones. The calculated results based on different combinations of basis sets show that the B3LYP (a hybrid of DFT with HF) predictions are greatly superior to the HF predictions. When a basis set of metal atom with effective core potential (ECP) has well representation of valence wavefunction, especially wavefunction of d component, and proper definition of core electron number, it can be applied to obtain 19F chemical shielding which is close to that of all‐electron calculation. The variation of 19F chemical shielding of alkaline‐earth‐metal fluorides correlates well with the lattice factor A/R2.