CuZSM-5分子筛上苯酚羟化制苯二酚

在Ｎａ２Ｏ－ＳｉＯ２－ＣｕＯ－Ｈ２Ｏ体系中以１５％ＴＰＡＢｒ－８５％ＨＭＤＡ为模板剂合成了ＣｕＺＳＭ－５分子筛，并用ＸＲＤ，ＩＲ及ＳＥＭ等方法进行了表征，考察了ＣｕＺＳＭ－５分子筛催化苯酚与过氧化氢的羟化活性，研究了催化剂用量、反应温度、反应时间及ｎ（ＰｈＯＨ）／ｎ（Ｈ２Ｏ２）等对羟化活性的影响．     

Ab initio study of the role of entropy in the kinetics of acetylene production in filament-assisted diamond growth environments

We present a new theoretical strategy, ab initio rate constants plus integration of rate equations, that is used to characterize the role of entropy in driving high-temperature/low-pressure hydrocarbon chemical kinetics typical of filament-assisted diamond growth environments. Twelve elementary processes were analyzed that produce a viable pathway for converting methane in a feed gas to acetylene. These calculations clearly relate the kinetics of this conversion to the properties of individual species, demonstrating that (1) loss of translational entropy restricts addition of hydrogen (and other radical species) to unsaturated carbon-carbon bonds, (2) rotational entropy determines the direction of the rate-limiting abstraction reactions, and (3) the overall pathway is enhanced by high beta-scission reaction rates driven by translational entropy. These results suggest that the proposed strategy is likely applicable to understand gas-phase chemistry occurring in the systems of combustion and other chemical vapor depositions.     

DFT/TDDFT Studies on the Electronic Structures and Spectral Properties of Carbazole‐based Blue Light‐emitting Dendrimers

The purpose of this paper is to provide an in‐depth investigation of the electronic and optical properties of two series of carbazole‐based blue light‐emitting dendrimers, including 1 – 6 six oligomers. These materials show great potential for application in organic light‐emitting diodes as efficient blue‐light and red‐light emitting materials due to the tuning of the optical and electronic properties by the use of different electron donors (D) and electron acceptors (A). The geometric and electronic structures of these compounds in the ground state are calculated using density functional theory (DFT) and the ab initio HF, whereas the lowest singlet excited states were optimized by ab initio single excitation configuration interaction (CIS). All DFT calculations are performed using the B3LYP functional on 6‐31G* basis set. The outcomes show that the highest occupied molecular orbitals (HOMOs), lowest occupied molecular orbitals (LUMOs), energies gaps, ionization potentials, electron affinities and reorganization energies of each molecular are affected by different D and A moieties and different substitute positions.     

恢复蛋白EF-hand与钙离子去耦合作用的拉伸分子动力学模拟

恢复蛋白Recoverin是一重要的神经钙传感蛋白. 为澄清EF-hand与Ca2＋耦合/去耦合作用机制, 采用拉伸分子动力学(SMD)方法对其进行了一系列等外力和等速度的非平衡分子动力学模拟. 研究结果表明EF-2和EF-3 loop区氨基酸螯合Ca2＋能力大小顺序分别为Asn-76＜Thr-80＜Glu-85＜Asp-74＜Asp-78和Thr-116＜Glu-121＜Asp-110＜Asn-114＜Asp-112. 结构域EF-3比EF-2耦合Ca2＋离子的能力强. EF-hand loop环中的Asp-78和Asp-112残基在该信号传导过程中起至关重要的作用. 基于理论模拟和试验结果我们推测Ca2＋离子诱导恢复蛋白的构象转变是一个两步过程. 在该细胞信号Ca2＋离子与恢复蛋白耦合过程中, EF-3和Ca2＋耦合作用触发恢复蛋白构象转变, 而EF-2和Ca2＋的耦合作用起续航作用, 促使变构过程完成.     

过度金属对缺位Keggin结构杂多化合物的修复

合成了第四周期过渡金属取代的Keggin结构钼磷、钨磷杂多化合物．讨论了合成条件，运用P－0键的IR振动变化表征了过渡金属离子电子组态的变化对缺位配体的修复作用．     

Evaluation of measurement uncertainty for thermometers with calibration equations

The method recommended by Eurachem did not mention the effect of adequateness of calibration equations on the measurement uncertainty. In this work, the sources of measurement uncertainty for two types of thermometer were evaluated. Three calibration equations were adopted to compare its predictive performance. These sources of combined uncertainty include predicted values of calibration equation, nonlinearity and repeatability, reference source, and resolution source. The uncertainty analysis shows that the predicted uncertainly of calibration equations is the main source for two types of thermometer. No significant difference of the uncertainty was found between the classical method and the inverse method. However, the calculation procedure of the inverse method was simpler and easier than that of the classical method.     

Calculations on the spectra and nonlinear third-order optical susceptibility of c70

The equilibrium geometry and UV-visible spectra of C₇₀ were examined using semiempirical INDO /2 and INDO /CI methods. The results obtained are in good accord with experimental results. On the basis of correct electronic spectra, calculations of the nonlinear third-order optical susceptibility (γijkl) of C₇₀ were performed using the INDO /SDCI method combined with a sum-over-states expression. The calculated value for <γ> (-2 ω, ω, ω, O) is 0.882 × 10^?33 esu (ω = 1.91 μm), which is in good agreement with observation. © 1994 John Wiley & Sons, Inc.     

Theoretical studies on the structure and electronic spectra of some isomeric fullerene derivatives C60On (n=2, 3)

Possible isomers of Buckminsterfullerene derivatives C₆₀O₂ and C₆₀O₃ are studied with the semiempirical quantum mechanical INDO method. The C₆₀O₂ isomer of C_s symmetry, where the epoxy oxygen atoms are on the 6–6 bond of a hexagon, is found most stable. The C₆₀O₃ isomer of C_3v symmetry with a single epoxy chain connecting both carbons of a 6–6 bond is most stable. However, the other two isomers of C₂ and C_s symmetries are near as stable. In all cases, the 6–6 carbon–carbon bond in the epoxial ring is not broken. Based on the structures so identified, the calculated electronic spectra of C₆₀O₂, and the ¹³C‐NMR analysis of both C₆₀O₂ and C₆₀O₃ agree well with experiment. The calculated electronic spectra of C₆₀O₃ are theoretical prediction. The chemical reactivity of C₆₀O₂ and C₆₀O₃ is discussed in connection with our calculated results. © 1999 John Wiley & Sons, Inc. Int J Quant Chem 76: 23–43, 2000     

Theoretical study on the structures, isomerization and stability of SiC4 isomers

The structures, energetics, dipole moments, vibrational spectra, rotational constants, and isomerization of singlet SiC₄ isomers were explored using ab initio methods. Five types of isomers, a total of 11 minima, connected by 11 interconversion transition states, were located on the potential energy surface at the MP2/6-311G(d, p) level. More accurate energies were obtained at the G3(MP2) level. With the highest isomerization barrier, a C2v tetra-angular cone possesses the largest kinetic stability. The lowest-lying structure, linear SiCCCC is also highly kinetically stabilized. Besides, D2d bicyclic c-Si(CC)₂, C2v five-membered ring c-SiCCCC, another C2v tetra-angular cone isomer and C3v trigonal bipyramid isomer are also considered to be kinetically stable, because their isomerization barriers are all over 10 kcal/mol. Other isomers cannot be kinetically stabilized with considerably low isomerization barriers. Investigation on the vibrational spectra, dipole moments, and rotational constants for SiC₄ isomers are valuable for their detections in the interstellar space and laboratory.     

Theoretical investigation on structures,stability and properties of [P,X, Y] (X=C,Si; Y = O,S) isomers

The structures, energetics and stability of the [P, X, Y] (X?=?C, Si; Y?=?O, S) radicals are explored by means of the density functional theory and ab initio levels. Seventeen [P, X, Y] isomers and 14 interconversion transition states are obtained at the B3LYP/6-311G(d) level. At the CCSD(T)/6-311?+?G(2df)//QCISD/6-311G(d)?+?ZPVE level, the lowest-lying isomers are the linear PCO 1a (0.0?kcal/mol), PCS 1b (0.0) and the three-membered ring cPSiO 1c (0.0), cPSiS 1d (0.0) on their respective potential energy surfaces. These four isomers exhibit considerably not only thermodynamic but also kinetic stabilities. Additionally, the cyclic cPCS 2b (32.8) and linear PSiS 2d (18.6) possess also high kinetic stability. All of six isomers 1a, 1b, 2b, 1c, 1d and 2d are considerably stabilized by a barrier of at least 20?kcal/mol, and may be detected in the laboratory or interstellar space. Their valence bond structures and possible formation strategies in the laboratory and space are discussed in detail. Finally, the similarities and discrepancies on structures and stabilities between [P, X, Y] (X?=?C, Si; Y?=?O, S) isomers are compared. These predicted results are highly expected to be informative for the future identification of [P, X, Y] (X?=?C, Si; Y?=?O, S) in the laboratory and space.