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Structures and stability of isomers of[Si,N,N,P]system

Science china chemistry 2004年第2期47卷 98-105页

作者： KAN Wei1, YU Haitao1, LI Mingxia1, FU Honggang1,2.& SUN Jiazhong1,2.1. college of {3. and Chemical {2., Heilongjiang {3., Harbin 150080, china 2. State Key Laboratory of Theoretical and Computational {3., Institute of Theoretical {3., Jilin {3., Changchun 13.02., china 1. college of chemistry and Chemical {2. Heilongjiang University 150080 Harbin China 2. State Key Laboratory of Theoretical and Computational chemistry Institute of Theoretical Chemistry Jilin University 130023 Changchun China

Some stationary points on the potential energy surface of [Si, N, N, P] system were located at the B3.YP/6-3.1G(d) and QCISD(t)/6-3.1+G(2.f)(single-point) levels of theory, while the isomerization, structures, and stability of these obtained isomers were suggested. The computed results indicate that only four-membered ring isomer SiNPN(E1, 2.'), which possesses butterfly-like structure and Si-P cross bonding, is kinetically stable in all optimized isomers. Other isomers may be considered as kinetically unstable towards isomerization or dissociation because of the corresponding smaller reaction barriers. Furthermore, the present paper also proposes electronic and geometric structures, vibrational frequencies and the corresponding vibrational modes, dipole moments, and rotational constants of isomer E1. To make use of the computed results, we can clearly know that the reaction pathway via an intermediate E3.(SiNPN) is the most favorable channel producing isomer E1 from fragments SiN(2.) and PN (1Σ), which have been well characterized in space, and thus, isomer E1 can be considered as a candidate for interstellar observation. The reaction enthalpy of SiN(2.) + PN(1Σ)→ E1 and the standard enthalpy of formation of isomer E1 are 2.5.2. and 457.99 kJ/mol, respectively, at 2.8.15 K. Keywords potential energy surface - [Si,N,N,P] system - isomerization - kinetic stability

关键词： potential energy surface, [Si,N,N,P] system, isomerization, kinetic stability.

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Luminescence resonance energy transfer based on β-NaYF_4:Yb,Er nanoparticles and TRITC dye

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Science china chemistry 2009年第10期52卷 1590-1595页

作者： SUN LingDong, GU JianQin, ZHANG ShuZhuo, ZHANG YaWen & YAN ChunHua Beijing National Laboratory for molecular Sciences, State Key Lab of Rare Earth Materials chemistry and Applications & PKU-HKU Joint Lab in Rare Earth Materials and Bioinorganic chemistry,{3. of chemistry and molecular engineering, peking university, Beijing 100871, china 1. Beijing National Laboratory for molecular Sciences State Key Lab of Rare Earth Materials Chemistry and Applications & PKU-HKU Joint Lab in Rare Earth Materials and Bioinorganic Chemistry College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

β-NaYF4:Yb,Er nanoparticles (NPs) are one of the most efficient upconversion materials, which can convert near-infrared light to higher-energy light through multiple photon absorptions or energy transfer. In addition, they may be attractive alternative donors for luminescence resonance energy transfer (LRET) studies, because of their sharp absorption and emission profiles, high quantum yields, large anti-stokes shifts, long lifetime, low toxicity, and superior photo-stability. In principle, many problems of fluorescence resonance energy transfer (FRET), such as excitation of acceptors, emission overlaps between donors and acceptors, high background noise, potential toxicity, and instability, can be overcome using β-NaYF4:Yb,Er NPs as energy donors. Because the organic coating induced separation can significantly reduce the energy transfer efficiency and aqueous FRET system is difficult to be applied in devices, we demonstrate a novel NP-dye LRET system in solid state. The emission of the β-NaYF4:Yb,Er NPs at 53. nm overlaps with the absorption of the tetrametrylrhodarnine isothiocyante (TRITC), satisfying the requirement of LRET process. Since TRITC molecules are adsorbed on the β-NaYF4:Yb,Er NPs by an electrostatic interaction, the interaction distance is suitable for LRET without any further modulation. The resultant solid LRET system is ready for the further applications for devices.

关键词： upconversion emission β-NaYF4:Yb Er nanoparticles TRITC assembly luminescence resonance energy transfer (LRET)

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Polycistronic strategy for cyanobacterial expression vector construction: Co-transcription of a human gene and a selective marker gene

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Progress in Natural Science:Materials International 2005年第9期15卷 798-803页

作者： ZHANG Yukun1, SHI Dingji2. ZHAO Feifei1, YU Meimin1 and RU Binggen1(1. college of Life Science, peking university, Beijing 100871,{2. 2. college of Marine Sciences & engineering, Tianjin university of Science & Technology, Tianjin 3.0450,{2.) college of Life Science Peking University Beijing 100871 China. college of Marine Sciences & engineering Tianjin University of Science & Technology Tianjin 300450 China

A polycistronic expression vector, pKGA-NTF1, was constructed for the cyanobacterium. Within this vector, the spectinomycin/streptomycin resistance gene (aadA) facilitated the selection of transformants when co-transcribed with favorite genes. A natural glnA gene was selected as the platform to introduce the plasmid into a neutral site of the Synechococcus sp. PCC 7002.chromosome. Function of the vector was demonstrated by the insertion of a modified human Trefoil factor 3.gene (NTF1) to upstream of the aadA gene and by the analyses of the transformed strains. Antibiotics resistance assays showed that the dicistronic expression cassette conferred high spectinomycin resistance to both the E. coli cells and the Synechococcus cells. PCR analysis and Western-blot analysis were carried out to confirm the integration and expression of the NTF1 gene, respectively. Through simple molecular manipulations, the artificial polycistronic structure described here can be conveniently used to express other favorable genes or operons in cyanobacteria, and to study the cyanobacterial gene expression as well.

关键词： cyanobacterial transformation human Trefoil factor 3 polycistronic expression Synechococcus sp. PCC 7002 vector construction.

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SMALL ANGLE LIGHT SCATTERING MEASUREMENT OF THE ISOTROPIC TO NEMATIC TRANSITION OF A SIDE CHAIN NEMATIC POLYMETHACRYLATE

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Chinese Journal of Polymer Science 2002年第5期20卷 431-437页

作者： Zhong-ming Hu Ren-yuan Qian Shou-xi Chen Xiao-fang Chen Qi-feng Zhou Centre for molecular Science, Institute of chemistry Chinese Academy of Sciences, Beijing 100080,{2. Department of Polymer Science &{3. college of chemistry & molecular{3. peking university Beijing 100871,{2. Chinese Acad Sci Inst Chem Ctr Mol Sci Beijing 100080 Peoples R China peking Univ Coll Chem & Mol Engn Dept Polymer Sci & Engn Beijing 100871 Peoples R China

The kinetics of I-->N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polymer shows the transition temperatures K52.79I in degreesC, The H-v scattering intensity T(q,t) during the transition I (at 80.2.egreesC)-->N (at 75.8degreesC) shows that T(q) is independent of q for all t, and during the initial stage (in 6 s) T(t) increases exponentially with t. In the later stage of the transition T(t) approaches a saturation value in 2.min. This experimental result indicates that the I-->N transition of a liquid crystalline polymer is a spinodal type of phase transition mediated by orientation fluctuation.

关键词： side chain nematic polymer isotropic-nematic transition small angle depolarized light scattering

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Study on interaction between macrocell and microcell in the early corrosion process of reinforcing steel in concrete

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Science china(Technological Sciences) 2010年第5期53卷 1285-1289页

作者： LI LanQiang1,DONG ShiGang1,WANG Wei2.HU RongGang1,DU RongGui1,LIN ChangJian1,ZHUO XiangDong1 & WANG Jia2.1 State Key Laboratory of Physical chemistry of Solid Surfaces,Department of chemistry,{2. of chemistry and Chemical engineering,Xiamen university,Xiamen 3.1005,china 2.{2. of chemistry and Chemical engineering,Ocean university of china,Qingdao 2.6100,china 1. State Key Laboratory of Physical chemistry of Solid Surfaces Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China2. College of Chemistry and Chemical Engineering Ocean University of China Qingdao 266100 China

An array electrode technique was developed as a novel electrochemical method for studying the interaction between macrocell and microcell in the early corrosion process of reinforcing steel in cement *** corrosion potential and galvanic current of macrocell corrosion of the reinforcing steel in cement mortar were imaged by the array electrode technique during the corrosion initiation and *** was certified that the corrosion macrocell current is closely related with the difference of corrosion potential between the anodic and cathodic *** corrosion macrocell and microcell always exist during the corrosion *** interaction of corrosion macrocell and corrosion microcell of steel in concrete was directly sensed by the array electrode for the first time,and was discussed in terms of corrosion electrochemistry.

关键词： reinforcing steel in concrete array electrode macrocell microcell

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Growth of Carbon Encapsulated Long Nickel Nanorods on Bulk Nickel Substrate

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Journal of Wuhan university of Technology(Materials Science) 2011年第1期26卷 28-32页

作者：宾晓蓓 college of Resources & Environment engineering Wuhan University of Technology

Carbon nanotube encapsulated nickel nanorods were catalytic grown via pyrolysis of oil on a bulk nickel wire substrate. X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy were employed to characterize the as-prepared sample. The results show that, carbon nanotubes possess several microns in length, the filled metallic nickel nanorods with a uniform diameter of 3. nm were tightly encapsulated by the carbon capsules. The detailed formation mechanism for the carbon nanotubes encapsulated nickel nanorods were discussed briefly.

关键词： carbon nanotube nickel nanorod pyrolysis core-shell

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Theoretical study on thermal decomposition of azoisobutyronitrile in ground state

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Science china chemistry 2004年第5期47卷 373-380页

作者： SUN Chengke1,2. ZHAO Hongmei1 & LI Zonghe1 1. Department of chemistry, Beijing Normal university, Beijing 100875,{2. 2. Department of chemistry, Qujing Normal college, Qujing 655000,{2. 1. Department of chemistry Beijing Normal University 100875 Beijing China 2. Department of chemistry Qujing Normal College 655000 Qujing China

The thermal decomposition mechanisms of azoisobutyronitrile (AIBN) in the ground state have been investigated systematically. Based on the potential energy surfaces (PES) of various possible dissociation paths obtained using the semiempirical AM1 method with partial optimization, the density function theory B3.YP/6-3.1G* method was employed to optimize the geometric parameters of the reactants, the intermediates, the products and the transition states, which were further confirmed by the vibrational analysis. The obtained results show that the re- action process of the two-bond (three-body) simultaneous cleavage Me2.CN)C─ N=N─ C(CN)Me2. 2.e2.CN)C?+N2.is much more favorable than the reaction process of the two one- bond asynchronous cleavage Me2.CN)CN=N─C(CN)Me2.? Me2.CN)CN=N?+ Me2.CN)C?? Me2.CN)C?+ N2. It was suggested that the electron shrinking effect of double bond (─N=N─) in AIBN and the stabilities of the Me2.CN)C?radical as well as N2.molecule are main factors of leading to the reaction proceeding in the former pathway. The calculation results were consistent with all the experimental facts.

关键词： azoisobutyronitrile, radicals, thermal decomposition, density function theory (DFT).

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Synthesis, Crystal Structures and Catalysis of Dinuclear Cd(Ⅱ) Complexes Bridged by Unusual (N,O,O′)-Coordinated α-Amino Acids

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Chemical Research in Chinese Universities 2012年第1期28卷 73-78页

作者： DENG Dong-sheng1,2. WANG Li1, PEI Ya-mei1, FENG Lu2.and LIU Chang-lin1 1. Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, School of chemistry, Central{3. Normal {2., Wuhan 43.079, P. R.{3. 2. college of chemistry and Chemical engineering, Luoyang Normal {2., Luoyang 47102., P. R.{3. School of chemistry Central China Normal University Key Laboratory of Pesticide & Chemical Biology Ministry of Education Wuhan 430079 college of chemistry and Chemical {2. Luoyang Normal University Luoyang 471022

Four dinuclear amino acid cadmium（II） complexes [Cd2.tren）2.dl-alaninato）]（ClO4）3.H2.（I）, [Cd2.tren）2. （l-alaninato）]（ClO4）3.H2.（II）, [Cd2.tren）2.dl-phenylalaninato）]（ClO4）3.III） and [Cd2.tren）2.l-phenylalaninato）]· （ClO4）3.IV）, constructed from mixed ligands of tris（2.aminoethyl）amine（tren） and racemic or natural amino ac ids（amino acids=dl or l-alanine, and dl or l-phenylalanine）, have been synthesized and characterized by X-ray crys tallography. The structural analysis of complexes I and III reveals that the cadmium centers are coordinated by one tren ligand and one amino acid molecule with the unusual （N,O,O′）-bridged mode, resulting in asymmetric chromo phores of CdN4O and CdN5O in complex I, CdN4O2.and CdN5O in complex III, respectively. The utility of the four complexes as efficient water-compatible Lewis acid catalysts for the direct aldol reaction in water was examined. The reaction proceeded smoothly to afford the corresponding β-hydroxy ketones in up to 99% yield. Moreover, the dias tereoselectivity of the reaction favors the formation of the syn-isomers.

关键词： Dinuclear cadmium(II) complex Amino acid Aldol reaction

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Theoretical studies on Ru(fppz)_2.CO)L (L=N-heterocyclic ligand):Electronic structure,absorption,phosphorescence,and solvatochromism

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Science china chemistry 2008年第12期51卷 1211-1220页

作者： LIU Tao1, ZHOU Xin1, BAI FuQuan1, ZHANG JianPo1, XIA BaoHui1,2. PAN QingJiang3.& ZHANG HongXing1 1 State Key Laboratory of Theoretical and Computational chemistry, Institute of Theoretical chemistry, Jilin {2., Changchun 13.02., china 2.college of chemistry, Jilin {2., Changchun 13.02., china 3.Laboratory of Physical chemistry, School of chemistry and Materials Science, Heilongjiang {2., Harbin 150080, china State Key Laboratory of Theoretical and Computational chemistry Institute of Theoretical Chemistry Jilin University Changchun 130023 China college of chemistry Jilin University Changchun 130023 China Laboratory of Physical chemistry School of Chemistry and Materials Science Heilongjiang University Harbin 150080 China

A series of ruthenium(II) complexes Ru(fppz)2.CO)L [fppz = 3.trifluoromethyl-5(2.pyridyl)pyrazole; L = pyridine (1), 4-dimethylaminopyridine (2., 4-cyanopyridine (3.] were designed and investigated theo-retically to explore their electronic structures, absorption, and emissions as well as the solvatochrom-ism. The singlet ground state and triplet excited state geometries were fully optimized at the B3.YP/LANL2.Z and CIS/LANL2.Z level, respectively. The HOMO of 1-3.is composed of dyz(Ru) atom and π(fppz). The LUMO of 1 and 2.is dominantly contributed by π*(fppz) orbital, but that of 3.is con-tributed by π*(L). Absorption and phosphorescence in vacuo, C6H12. and CH3.N media were calculated using the TD-DFT level of theory with the PCM model based on the optimized ground and excited state geometries, respectively. The lowest-lying absorption of 1 and 2.at 3.7 and 3.1 nm is attributed to {[dyz(Ru) + π(fppz)] → [π*(fppz)]} transition, but that of 3.at 479 nm is assigned to {[dyz(Ru) + π(fppz)] → [π*(L)]} transition. The phosphorescence of 1 and 2.at 43. and 43. nm originates from 3.[dyz(Ru) + π(fppz)] [π*(fppz)]} excited state, while that of 3.at 606 nm is from 3.[dyz(Ru) + π(fppz)] [π*(L)]} excited state. The calculation results showed that the absorption and emission transition character can be changed from MLCT/ILCT to MLCT/LLCT transition by altering the substituent on the L ligand. The phosphorescence of 1 and 2.does not have solvatochromism, but that of 3.at 606 nm (vacuo), 584 nm (C6H12., and 541 nm (CH3.N) is strongly dependent on the solvent polarity, so introducing elec-tron-withdrawing group on ligand L will induce remarkable solvatochromism.

关键词： ruthenium complex DFT phosphorescence solvatochromism

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Heat capacity and thermodynamical properties of the crystal of [RE_2.Glu)_2.H_2.)_8](ClO_4)_4·H_2. (RE = Nd, Eu, Dy)

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Science china chemistry 2009年第7期52卷 862-867页

作者： WU XinMin1, LI Wei1, TAN ZhiCheng2.& QU SongSheng3.1 Department of Chemical engineering, Beijing Institute of Petro-chemical Technology, Beijing 102.17,{3. 2.Thermo{2. Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 11602.,{3. 3.college of {2. and molecular Science, Wuhan university, Wuhan 43.072.{3. Department of Chemical engineering Beijing Institute of Petro-chemical Technology Beijing 102617 China Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China college of chemistry and {2. Science Wuhan University Wuhan 430072 China

Thermodynamical data of rare earth complexes with amino acid are important for engineering chemistry and fundamental chemistry. However, they have rarely been reported. In this work, a series of crystalline complexes of rare earth perchlorate coordinated with glutamic acid have been synthesized in water medium, and their thermodynamical data, including the heat capacity in low temperature range and the standard enthalpy of formation, were determined. These complexes were identified to be [RE{3.Glu){3.H{3.)8](ClO4)4·H{3. (RE = Nd, Eu, Dy) by using thermogravimetric analysis (TG), differential thermal analysis (DTA), and chemical and elementary analyses. Their purity has been determined. No melting points were observed for all the three complexes. The heat capacity of the complexes was measured by an adiabatic calorimeter from 79 to 3.0 K. Abnormal heat capacity values were detected for two of the complexes and the decomposition range of one complex was found. The temperature, enthalpy change and entropy change of the decomposition processes of the three complexes were calculated. The polynomial equations of heat capacity in the experimental temperature range have been obtained by least squares fitting. The standard enthalpy of formation was determined by an isoperibol reaction calorimeter at {3.8.15 K.

关键词： complex of rare earth, [RE2.Glu)2.H2.)8](ClO4)4·H2. (RE = Nd, Eu, Dy Glu = glutamic acid), low-temperature heat capacity, standard enthalpy of formation

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