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Theoretical study on S_1(~1B_(3.)) state electronic structure and absorption spectrum of pyrazine

Science china chemistry 2008年第12期51卷 1166-1173页

作者： HE RongXing1, ZHU ChaoYuan 2. CHIN Chih-Hao3.& LIN Sheng-Hsien2.3.1 {2. of chemistry and Chemical engineering, Southwest {3., Chongqing 400715, china 2.Department of Applied chemistry, Institute of molecular Science and Center for Interdisciplinary molecular Science, National Chiao-Tung {3., Hsinchu 3.0, china 3.Institute of Atomic and molecular Sciences, Academia Sinica, Taipei 106, china college of chemistry and Chemical {2. Southwest University Chongqing China Department of Applied chemistry Institute of Molecular Science and Center for Interdisciplinary Molecular Science National Chiao-Tung University Hsinchu China Institute of Atomic and molecular Sciences Academia Sinica Taipei China

Making use of a set of quantum chemistry methods, the harmonic potential surfaces of the ground state (S0(1Ag)) and the first (S1(1B3.)) excited state of pyrazine are investigated, and the electronic structures of the two states are characterized. In the present study, the conventional quantum mechanical method, taking account of the Born-Oppenheimer adiabatic approximation, is adopted to simulate the absorp-tion spectrum of S1(1B3.) state of pyrazine. The assignment of main vibronic transitions is made for S1(1B3.) state. It is found that the spectral profile is mainly described by the Franck-Condon progression of totally symmetric mode ν6a. For the five totally symmetric modes, the present calculations show that the frequency differences between the ground and the S1(1B3.) state are small. Therefore the displaced harmonic oscillator approximation along with Franck-Condon transition is used to simulate S1(1B3.) absorption spectra. The distortion effect due to the so-called quadratic coupling is demonstrated to be unimportant for the absorption spectrum, except the coupling mode ν10a. The calculated S1(1B3.) ab-sorption spectrum is in reasonable agreement with the experimental spectra.

关键词： pyrazine absorption spectrum quantum mechanical method electronic structure

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Density functional theory study of the magnetic properties of rare earth complexes:the magnetic coupling mechanism in Y~Ⅲ and Gd~Ⅲ complexes with nitronyl nitroxide

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Science china chemistry 2009年第11期52卷 1961-1968页

作者： REN Jie1,2.WANG BingWu1 & CHEN ZhiDa1 1 Beijing National Laboratory for molecular Sciences,State Key Laboratory of Rare Earth Materials chemistry and Applications,{2. of chemistry and molecular engineering,peking university,Beijing 100871,china 2.{2. of Science,Hebei university of Science and Technology,Shijiazhuang 050018,china Beijing National Laboratory for molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing China college of Science Hebei University of Science and Technology Shijiazhuang China

The magnetic coupling interactions of the nitronyl nitroxide radicals bound to diamagnetic(YⅢ) and paramagnetic(GdⅢ) rare earth ions in two model magnetic systems based on novel rare earth organic radical complexes Ln(hfac)3.NITPhOCH3.2.Ln=YⅢ 1,GdⅢ 2.hafc = hexafluoroacetylacetonate;NIT-PhOCH3.= 4'-methoxyo-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3.oxide) have been investigated by density functional theory(DFT).The magnetic coupling mechanisms were also explored from the viewpoint of molecular orbital and spin density *** calculations show that the empty 4d-orbitals of YⅢ and 5d-orbitals of GdⅢ play an important role in the antiferromagnetic coupling between the two nitronyl nitroxide radical ligands,and that the ferromagnetic coupling between the GdⅢ ion and the radical magnetic centers can be attributed to the nearly complete localization of the isotropic 4f-shell and singly occupied magnetic orbital(π) of the nitronyl nitroxide.

关键词： magnetic coupling density functional theory rare earth ion gadolinium(Ⅲ) complexes yttrium(Ⅲ) complexes

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Microwave-assisted reaction of peptide formation by amino acid with phosphate:Exploration of the most possible channels for the origin of life

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Science china chemistry 2006年第4期49卷 351-356页

作者： HU Rong1, TIAN Jinping2.& YIN Yingwu2.3.1. college of {2. & Environment Protection engineering, Southwest {3. for Nationalities, Chengdu 610041, china 2. TH-UNIS Insight Co., Ltd., Beijing 100085, china 3. Key Laboratory of Bioorganic Phosphorus {2. & Chemical Biology, Ministry of Education, Department of {2., Tsinghua {3., Beijing 100084, china college of chemistry & Environment Protection {2. Southwest University for Nationalities Chengdu China TH-UNIS Insight Co. Ltd. Beijing China Key Laboratory of Bioorganic Phosphorus chemistry & Chemical Biology Ministry of Education Department of Chemistry Tsinghua University Beijing China

Microwave-assisted reaction of peptide formation by amino acids with phosphate was studied. The results showed that the products were a mixture of peptides containing dipeptide, oc- tapeptides and cyclic peptides, which could be obtained in a short time. Polyphosphate was also produced synchronously by the intermolecular condensation of phosphate. The polymerization de- gree reached 99% (pyrophosphate 64%, trimetaphosphate 3.%) after 2.h at 2.0℃ under microwave irradiation. The intermediates of the mixed anhydrides formed by the intermolecular condensation of phosphates and glycin were determined by ESI-MS. Peptides were also produced by the reaction of amino acids with trimetaphosphate in aqueous solution. The conversion degree of valine reached 46.5% even at room temperature. The cyclic process of peptide formation and phosphate polymeri- zation, regeneration and utilization in amino acids-phosphate system under microwave irradiation was detected and proved. Peptides could be continually formed only by inputting energy into this system. The above recycle may be the most possible process for primitive peptide formation in the origin of life.

关键词： microwave, phosphate, amino acid, peptide, origin of life.

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SYNTHESIS OF PERFLUORO-1-OCTANESULFONATED FULLERENE AND THE FRICTION PROPERTIES OF ITS THIN FILM

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Chinese Journal of Polymer Science 2002年第5期20卷 397-400页

作者： Lan Huang Shuang Fan Fang Wei Xin-sheng Zhao Jin-xin Xiao Bu-yao Zhu college of chemistry and {2. {3. peking university Beijing 100871, china college of chemistry and {2. {3. Peking University 北京 100871

A star-shaped compound of perfluoro-1-octanesulfonated fullerene was synthesized. The measurement of the friction for its spin-coating film by friction force microscopy (FFM) reveals that the films possess lower frict... 详细信息

关键词： perfluoro-1-octanesulfonated fullerene thin film friction force microscopy (FFM)

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Cellulose conversion to polyols on supported Ru catalysts in aqueous basic solution

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Science china chemistry 2010年第7期53卷 1476-1480页

作者： DENG TianYin,SUN JiYing & LIU HaiChao Beijing National Laboratory for molecular Sciences,State Key Laboratory for Structural chemistry of Stable and Unstable Species Green chemistry Center,{3. of chemistry and molecular engineering,peking university,Beijing 100871,china Beijing National Laboratory for molecular Sciences State Key Laboratory for Structural Chemistry of Stable and Unstable Species Peking University Beijing China Green chemistry Center College of Chemistry and Molecular Engineering Peking University Beijing China

It is of great significance and challenge to achieve direct conversion of cellulose to specific polyols,e.g.,ethylene glycol and propylene *** such selective conversion,a novel one-pot approach was studied by combination of alkaline hydrolysis and hydrogenation on supported Ru catalysts.A wide range of bases including solid bases,e.g.,Ca(OH)2.and La2.3.and phosphate buffers were examined in the cellulose reaction in water,and the cellulose conversions and polyol products depended largely on the basicity or pH values in the aqueous *** glycol,1,2.propanediol,and especially 1,2.5-pentanetriol were obtained with selectivities of 15%,14% and 2.%,respectively,at 3.% cellulose conversion at pH 8 in phosphate buffer *** preliminary results provide potentials for efficient conversion of cellulose to targeted polyols by using the advantages of bases.

关键词： cellulose polyols Ru catalysts solid bases aqueous basic solutions

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The Grand Canonical Monte Carlo Simulations of Benzene and Propylene in ITQ-1 Zeolite

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Chinese Chemical Letters 2000年第7期11卷 623-626页

作者： Li Li ZHU, Ting Jun HOU Xiao Jie XU(college of chemistry and {2. {3., peking university, Beijing 100871) Coll. of Chem. and Molec. Eng. Peking University Beijing 100871 China

Grand Canonical Monte Carlo (GCMC) simulations have been performed to study the localization and adsorption behavior of benzene and propylene, in purely siliceous MWW zeolite (ITQ-1). By analyzing the locations of benzene and propylene in ITQ-1, it can be deduced that the alkylation of benzene and propylene will mainly happen in 12.MR supercages at the external surface or close to the external surface. The adsorption isotherms of benzene and propylene at 3.5K and 0 similar to 3.5kPa are predicted, and the results for benzene generally coincide with the trend from the experiments of a series of aromatic compounds.

关键词： Grand Canonical Monte Carlo (GCMC) ITQ-1 adsorption diffusion

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“LIVING”/CONTROLLED RADICAL POLYMERIZATION OF ETHYL METHYLACRYLATE WITH 2.2.-AZOBISISOBUTYRONITRILE/FERRIC CHLORIDE/TRIPHENYLPHOSPHINE INITIATION SYSTEM

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Chinese Journal of Polymer Science 2000年第2期18卷 149-153页

作者： Xiao-ping Chen Kun-yuan Qiu Department of Polymer Science and engineering, college of {2.,{3., Beijing 100871, china 北京大学北京

'Living'/controlled radical polymerization of ethyl methacrylate (EMA) was carried out with a 2.2.-azobisisobutyronitrile (AIBN)/ferric chloride (FeCl_3./triphenylphosphine (PPh_3. initiation system at 85℃. Thc numberaverage {2. weight (M_n) increases linearly with monomer conversion and the rate of polymerization is first order withrespect to monomer concentration. The M_w of PEMA ranges from 3.00 to 17600 and the polydispersity indices are quitenarrow (1.09～1.2.). The conversion can reach up to～100% and M_w of the polymers obtained is close to that designed. Thepolymerization mechanism belongs to the reverse atom transfer radical polymerization (ATRP). The polymer was end-functionalized by chlorine atom, which acts as a macroinitiator to proceed extension polymerization in the presence ofCuBr/bipy catalyst system via an ATRP process. The presence of ω-chlorine in the PEMA obtained was identified by ~1H-NMR spectrum.

关键词： 'Living'/controlled radical polymerization Reverse ATRP Ethyl methacrylate AIBN/FeCl_3.PPh_3 Bulk polymerization

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Silylated and acetylated β-cyclodextrins for gas chromatographic stationary phases

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Journal of Central South university of Technology 2001年第4期8卷 239-243页

作者： TANG Ke wen 1,2.,YI Jian ming 2.ZHOU Chun shan 1,ZHONG Shi an 1 (1. college of chemistry and Chemical {2., Central South {3., Changsha 410083. china 2. college of chemistry and Chemical {2., Yueyang Normal {3. college of chemistry and Chemical {2. Central South University Changsha China college of chemistry and Chemical {2. Yueyang Normal University Yueyang China

Two new chiral stationary phases, 2.3.di O acetyl 6 O trimethylsilyl β cyclodextrin (DATBCD) and 2.6 di O trimethylsilyl 3.O acetyl β cyclodextrin(DTABCD), were synthesized, their structures were identified by means of infrared and NMR spectra. Capillary columns were coated with the two stationary phases by dynamic method. The chromatographic properties, and enantiomers separation, such as ketone, esters, alcohols and olefines, were investigated on the silylated and acetylated β cyclodextrin stationary phases. The experimental results show that the silylated and acetylated β cyclodextrins are suitable to be used as capillary gas chromatographic stationary phases, the relative polarity of DATBCD and DTABCD stationary phases is respectively 4143.and 3.2., the column efficiencies are respectively 3.84 and 4198, and DATBCD is of stronger enantioselectivity than DTABCD, capacity factor of the first eluted enantiomer ( k 1) and separation factor(α)of α phenylethanol on DATBCD stationary phase are respectively 8.2.0}and 1.019.

关键词： capillary gas chromatography silylated and acetylated β-cyclodextrins enantiomeric separation

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An efficient chiral synthesis of (R)-N-[3.acetyl-4-(2.hydroxy-3.isopropylamino-propoxy)phenyl]-butanamide with high enantioselectivity

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Science china chemistry 2009年第8期52卷 1216-1219页

作者： WANG NaiXing1,2.& TANG XinLiang1,3.1 Technical Institute of Physics and chemistry,Chinese Academy of Sciences,Beijing {2.,china 2.{3. of chemistry and Chemical engineering,Graduate university of Chinese Academy of Sciences,Beijing 100049,china 3.School of Chemical engineering and Environment,Beijing Institute of Technology,Beijing 100081,china Technical Institute of Physics and chemistry Chinese Academy of Sciences Beijing China college of chemistry and Chemical {2. Graduate University of Chinese Academy of Sciences Beijing China School of Chemical engineering and Environment Beijing Institute of Technology Beijing China

R-Enantiomer of the β-receptor antagonist N-[3.acetyl-4-(2.hydroxy-3.isopropylamino-propoxy)phenyl] butanamide with high enantioselectivity was synthesized from cheap starting materials and enantiopure chiral reagent through an efficient,convenient and practical synthetic *** product was detected by 1H NMR,13. NMR,and MS,and the enatiomeric excess was determined by chiral HPLC analysis using a chiracel AD-H column.

关键词： chiral synthesis enantioselectivity enatiomeric excess chiral HPLC analysis

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SYNTHESIS AND PROPERTIES OF A NEW AZOBENZENE SIDE-CHAIN POLYMER CONTAINING A TEMPO RADICAL

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Chinese Journal of Polymer Science 2002年第4期20卷 285-290页

作者： Yong Zhang Ze-da Xu Xing-he Fan Xiao-fang Chen Xin-hua Wan Qi-feng Zhou Department of Polymer Science and engineering college of {2. and {3. engineering peking university, Beijing 100871, china Department of Polymer Science and engineering College of Chemistry and Molecular Engineering Peking University 北京 100871

To allow anisotropies of optical properties in a magnetic field, nitroxide radical is introduced into the ortho-position of the phenylene ring in the side chain. A new azobenzene side-chain polymer (TEMPO-PAZ) containing TEMPO radical was synthesized. The polymer has a good solubility in organic solvents. The ESR spectrum of the polymer indicated three absorption lines characteristic of TEMPO radical. The optical phase conjugated responses (I-4) of the polymer films were investigated by degenerate four-wave mixing (DFWM). The experimental results showed that optical phase conjugated response of the TEMPO-PAZ could be easily controlled by choosing the appropriate direction of magnetic field presumably due to the nitroxide radical in the TEMPO-PAZ molecular structure. For the polymer investigated here, the nitroxide radical was introduced to increase optical phase conjugated response intensity in a magnetic field, aiming originally at searching for a new photo-active organic magnetic multifunctional materials.

关键词： azobenzene nitroxide radical polymer photo-active organic magnetic materials optical phase conjugated responses

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