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Chinese Journal of Chemistry 2005年第5期23卷 517-520页

作者：樊建芬卢运祥王秋霞吴丽芬 DepartmentofChemistry SuzhouUniversitySuzhouJiangsu215006China

am1 transition state (TS) models were developed for the enantioselectivities in the reductions of α‐ and β‐aminoketones catalyzed by ( S )‐4‐benzyl‐5,5‐diphenyl‐1,3,2‐oxazaborolidine. The result showed that β‐aminoketone gave better enantioselectivity than its α‐analog. Different chiralities of the final products were obtained, R for the former and S for the latter. These semiempirical TS models are consistent with the experimental data.

关键词： am1 enantioselectivity α‐ and β‐aminoketones reduction chiral oxazaborolidine

am1 and ab initio studies on the internal reorganization energy of self-exchange electron transfer reactions of several quinone derivatives

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Chinese Science Bulletin 2001年第15期46卷 1242-1251页

作者： Shuhua Ma Xiaodong Zhang Hong Xu Xingkang Zhang Qiyuan Zhang State Key Laboratory for Structural Chemistry of Unstable & Stable Species Center of Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing China

The semiempirical amI method, ah initio (HF/3-21G, 6-31G, 6-31G(d), 6-31+G(d)) and DFT (B3LYP/6-31G(d), 6-31+G(d)) methods were used to optimize the geometry of DDQ and its anion radical DDQ-. Nelsen’s model was used to calculate the internal reorganization energy λi of self-exchange electron transfer (ET) reactions. The calculated λi results of DDQ/DDQ-. by am1 and B3LYP/ 6-31G(d), 6-31+G(d) methods are close to each other and consistent with the reported values; while those from Har-tree-Fock methods are too large because of not consideringthe effect of electron correlation. The structure and ET behavior of MQ0 /MQ0- couple were studied by am1 and DFT (B3LYP/6-31G(d), 6-31+ G(d, p)) methods, and those of MQ0 /MQn-(n=1-7) were studied by am1 method for the first time. The results indicate that the values of the heat of formation of MQn increases with the increasing of the length of the isoamylene substituent chains. It also shows that the length of substituent has little effect on the bond lengths,

关键词： DDQ menaquinone (MQn) self-exchange electron transfer internal reorganization energy am1 ab initio DFT.

Mechanism of the interaction of color reagent 1, 3-N, N'-bis-4-(4'-nitro benzenediazo) phenyl squaraine with oxoacid anions

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Science China Chemistry 1999年第1期42卷 70-76页

作者：杨明理孙泽民鄢国森 Department of Chemistry Sichuan Union University Chengdu China

By am1 method, the interactions between 1, 3-N, N′-Bis-4-（4′-nitro benzenediazo） phenyl squaraine （BNBPS） and several oxoacid anions have been studied on the basis of the proposed model. The mechanism of the color reactions is suggested and the answers to the question of whether or not BNBPS colorates with HCO3-, CO32-, NO2-, NO3-, etc. are given. It is theoretically predicted that BNBPS might be used as the color reagent for SO42-.

关键词： anion color reagent squaraine derivatives am1 method.

Theoretical Study on the Structures and Electronic Spectra of the Derivatives of C_(60)-P-2,4,6-Triphenyl Borazinc

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Chinese Journal of Structural Chemistry 2005年第10期24卷 1140-1144页

作者： JIANG Qi-Jun Department of Chemistry Xiaogan University Xiaogan 432000 China

The structures and electronic spectra of the derivatives of C60-P-2,4,6-triphenyl borazinc have been studied by using am 1 method. The calculated results indicate that this kind of compounds has a lower energy difference between HOMO and LUMO. It is found that the electron cloud on unoccupied frontier orbital mainly comes from the contribution of C60, while that on occupied frontier orbital mainly concentrates on the side chain. A long-lived charge-separated state may occur in the objective compounds.

关键词： derivatives of C60-P-2,4,6-triphenyl borazinc electronic spectra charge-separated state am1

Relationship between Structures and Carcinogenicities of Heterocyclic amines

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Chemical Research in Chinese Universities 2004年第6期20卷 774-777页

作者： JUXue-hai DAIQian-huan CHENSha WANGWen-jun DepartmentofChemistry NanjingUniversityofScienceandTechnologyNanjing210094P.R.China CenterforEnvironmentalScience PekingUniversityBeijing100871P.R.China CenterforChemistryandBioengineeringofCancer BeijingPolytechnicUniversityBeijing100022P.R.China

Semi-empirical molecular orbital calculations were performed on heterocyclic aromatic amines(HCAs). The relationship between the structures and the carcinogenicities can be rationally elucidated by the models based on the metabolism of HCAs and the Di-region theory. The degree of easiness for the formation of Di-region electrophilic centers determines the carcinogenic activity. There is a good linear relationship between the observed carcinogenicities and the PM3 calculated parameters, with r=0.973 and F=29.8>F ** 0.01 .

关键词： Heterocyclic amine(HCA) Carcinogenicity QSAR am1 PM3

Theoretical study of intramolecular proton transfer of perylenequinone

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Science China Chemistry 1998年第1期41卷 85-90页

作者：张红雨张志义 Institute of Biophysics Chinese Academy of Sciences Beijing China

am1 method is employed to calculate the barriers against intramolecular proton transfer (IPT) of perylenequinone (PQ). The results obtained are as follows: (i) Barriers against the IPT reaction of ground state, singlet excited state and triplet excited state of PQ are 89.75, 55.40 and 83.97 kJ/mol, respectively. (ii) Barriers against the IPT process of anion of PQ in ground state and singlet excited state are 80.12 and 79.91 kJ/mol, respectively. (iii) Barriers against the IPT of cation and anion radical of PQ (PQ ·+ and PQ ·- ) are 65.94 and 59.29 kJ/mol. (iv) The barrier against double proton transfer of PQ is 172.13 kJ/mol. (v) Two barriers against IPT of a type of perylenequinonoid photosensitizer (PQP), hypocrellin A (HA), are 89.24 and 88.07 kJ/mol. From these data conclusions can be drawn as follows: (i) IPT processes in ground state and excited state of PQ exist, but the transfer rate of excited state is much higher than that of ground state. (ii) It is almost impossible for PQ to transfer two protons simultaneously. (iii) IPT processes in anion, anion radical and cation radical of PQ still exist. (iv) The seven membered side ring of HA has no marked influence on its barrier against IPT.

关键词： perylenequinone (PQ) perylenequinonoid photosensitizer (PQP) hypocrellin A (HA) intramolecular proton transfer (IPT) am1 method.

Investigation on the computation of atomic multipole moments with the modified cumulative potential-derived semiempiricalmethod

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Chinese Journal of Chemistry 1997年第6期15卷 481-491页

作者： Xu, LJ Zhu, CB Yan, JM Chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

The suitability of calculating atomic multipole moments from am1 wave functions by cumulative potential-derived method has been investigated. It is shown that this method has a faster convergence of the fitting process and gives a better description of the charge distribution than the original PD method. Atomic charges obtained in this way are of comparable quality with 6-31G* data and the calculated dipole moments are closer to the experimental data than the values computed directly from the am1 charges. The results demonstrate that the atomic multipole moments higher than monopole moment can be used to supplement the atomic charge to obtain a more accurate description of charge distribution. For the sake of comparison, both the Williams fitting potential surface and the Connolly one are used in the calculation.

关键词： atomic charge atomic multipole moment cumulative fitting am1

Synthesis,Crystal Structure and Conformational Analysis of (E)-5-Methoxy-2-((4-methoxyphenylimino)methyl)phenol

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Chinese Journal of Structural Chemistry 2010年第3期29卷 359-364页

作者： ■AHN Onura BYKGNGR Orhana ALBAYRAK i■demb ODABA■O■LU Mustafac Department of Physics Faculty of Arts and SciencesOndokuz Mayis University Department of Science Education Sinop University Chemistry Programme Pamukkale University

The title compound,（E）-5-methoxy-2-（（4-methoxyphenylimino）methyl）phenol（C15H15NO3）,crystallizes in monoclinic,space group P21/c with a=9.4361（6）,b=10.6212（5）,c=12.9338（9）,β=93.064（5）o,V=1294.41（14）3,Z=4,Dc=1.320 g/cm3,F（000）=544,Rint=0.116,T=296 K,μ=0.09 mm-1,the final R=0.051 and wR=0.148 for 1836 observed reflections with I2σ（I）.An extensive two-dimensional network of C–H…O hydrogen bonds and π-ring interactions are responsible for the crystal stabilization.Intermolecular hydrogen bonds and C–H…π interactions produce R22（14）,R44（30） and R44（31） rings.In addition to the molecular geometry from X-ray experiment,the molecular geometry of the title compound in the ground state has been calculated using the semi-empirical（am1 and PM3） and density functional theory method（DFT）（B3LYP） with 6-31G（d） basis set.To determine the conformational flexibility,molecular energy profile of the title compound was obtained by semi-empirical（PM3 and am1） and DFT/B3LYP calculations with respect to the selected degree of torsional freedom,which varied from –180° to ＋180° in a step of 10°.

关键词： crystal structure Schiff base PM3 am1 DFT conformational analysis

Theoretical elucidation of structure-activity relationship of flavonoid antioxidants

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Science China Chemistry 1999年第1期42卷 106-112页

作者：张红雨 Departmrnt of Biology Provincial Key Laboratory of Animal Resistance Biology Shandong Teachers University Jinan China

am1 method was employed to calculate flavonoid antioxidants, and the results obtained are as follows. Firstly, flavonoid hydroxyls at ortho position were more active than the hydroxyls at meta position in scavenging oxygen-free radicals, which resulted from the facts that (ⅰ) the former were stabilized by forming intramolecular hydrogen bond and (ⅱ) ortho benzoquinone formed in the former structures through resonance, which resulted in large percentage of distribution of spin density on ortho oxygen and low internal energy. Secondly, electron-attracting effect of ring C of chromone-flavonoids showed some passive effects on hydroxyls of ring A, making the OH less active. As ring C had little effect on ring B and hydroxyls of ring B in most flavonoids were at ortho position, the rule summarized from experiments showing that hydroxyls of ring B were more active in scavenging oxygen-free radicals was elucidated.

关键词： flavonoid antioxidants am1 method structure-activity relationship theoretical elucidation.

Is HOMO Energy Level a Good Parameter to Characterize Antioxidant Activity

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Chinese Chemical Letters 2000年第8期11卷 727-730页

作者： Hong Yu ZHANG De Zhan CHEN Department of Biological and Chemical Engineering Zibo UniversityZibo 255091 Department of Chemistry Shandong Teachers'UniversityJinan 250014

Semiempirical quantum chemical method am1 was employed to calculate the highest occupied molecular orbital (HOMO) energy levels (E-HOMO) for various types of antioxidants. It was verified that the correlation between logarithm of free radical scavenging rate constants (1gks) and E-HOMO substantially arises from the correlation between E-HOMO and O-H bond dissociation energies (BDE) of antioxidants. Furthermore, E-HOMO were poorly correlated with the logarithm of relative free radical scavenging rate constants (1gk(3)/k(1)) for various types of antioxidants that possess complex structures (r = 0.5602). So in a broad sense, E-HOMO was not an appropriate parameter to characterize the free radical scavenging activity of antioxidants.

关键词： am1 antioxidant free radical HOMO energy level O-H bond dissociation energy structure-activity relationship