芬太尼及其哌啶季铵离子的电子结构研究

改进了CNDO/2计算机程序,可减少对高速内存的要求,从而实现在65K内存的计算机上对价轨道在150个以内的大药物分子的半经验自洽场计算。对芬太尼分子及其哌啶季铵离子进行了CNDO/2半经验分子轨道计算,讨论了它们的电子结构特征,指出了它们与受体作用时可能的活性中心及其作用性质。     

铁超氧化物歧化酶活性中心结构研究

对氧化型、还原型及非活性形式铁超氧化物歧化酶Fe-SOD活性中心进行了量子化学计算和比较。在HF方法及LANL2DZ基组水平上获得了分子轨道能量、电荷分布以及原子轨道对前沿分子轨道贡献的信息。结果表明, Fe-SOD酶的活性形式的活性中心易于接受超氧自由基(O2- )的进攻而完成其生理功能。     

预测环加成反应区域选择性的一个简易方法

长期以来,我们一直在研究化合物的性能与结构关系的定量化问题,其目的是为了寻求一个定量确定反应物反应活性的简易方法。本文研究了一种确定环加成反应区域选择性的新方法。早在七十年代初期,对于环加成反应的区域选择性问题就有报导,可以通过分子轨道法等加以确定。但是,应用分子轨道法的计算程序过于繁琐,所以应用并不广泛。1989年,S.K.Pal提出了处理这个问题的一个方程,即可以通过活性中心原有的电负性进行推算。这种原有的电负性可以用Huheey方法计算,但是这种计算方法在应用中仍然是相当复杂     

过渡金属化合物的CNDO计算(Ⅱ)——α-Fe吸附分子氮的活性中心模型

本文采用自旋非限制的CNDO-SCF方法研究了α-Fe吸附分子氮的活性中心模型,讨论了各种吸附模型的N_2活化程度,以及各种原子簇模型的费米能级、分子轨道系数等。     

Waugh-型镍钼杂多酸的量子化学计算

采用半经验INDO法，完成了Waugh-型镍钼杂多酸（NH44）6〔NIMO9O32〕·6H2O的量子化学计算，得到146个成键轨道和78个反键轨道，轨道能级，电荷和键序等数据。通过对这些数据的分析，表明杂多酸分子中端氧和Ni都可能为化学活性中心，各原子轨道在分子轨道中都占有一定比例，其HOMO和LUMO能级皆为负值，其体系具有进一步接受电子的能力。这些结论与实验事实一致。     

氧电催化材料的多自由度思考

氧电催化反应的活性与析氧反应和氧还原反应的热动力学驱动机制密切相关。从多自由度角度考虑，包括系统自由度和量子自由度两方面。系统自由度包括形貌工程、晶格工程和配位工程等，量子自由度包括电子自旋、轨道耦合和分子键自由度等，本质均是调节活性中心和中间体分子的轨道耦合强度。因此，突破中间体自身吸附自由能的线性关系，寻找新的氧耦联路径是提高氧电催化反应活性的一个关键方向。同时，控制活性中心和惰性中间体的分子轨道，实现质子化和脱质子化的过程也是提高反应活性的有效途径。这些新思路将有助于设计高效的催化剂，为能源领域的可持续发展做出贡献。     

几种硫醚化合物的紫外光电子能谱及量子化学研究

报导了硫酸系列化合物DMS（二甲基硫酸），DpCPS（二对氯苯硫酸），DpTS（二对甲基苯硫醚）气相HcI紫外光电子能谱（UPs），其中DpCPS，DpTS的UPS谱为首次获得．对各体系利用MNDO方法进行了分子构型优化，对优化得到的优势构型实施RHF／6－31G量子化学计算，并利用计算结果对各个分子体系的UPS谱进行了指认，计算结果分析显示：a）S原子的孤对电厂在DpCPS和DpTS中起到阻碍形成遍及整个分子体系π轨道的阻断作用，故此不存在遍及整个分子体系的π轨道；b）通过对三体系第一电高能的对比分析表明，第一电高能所激发出的电子主要是受S原子的束缚；c）还得到另一个有意义的结论──各分子体系的第一电离能大小与HOMO中3Pz轨道所占成份成有很好的线性关系．表明体系的第一电离出的电子主要是受S原子的3Pz轨道束缚     

氨基酸卟啉锌配合物对氨基酸酯的分子识别

本文用紫外－可见吸收光谱滴定方法研究了一种新型的苏氨酸卟啉锌配合物（主体分子）对氨基酸酯（客体分子）的分子识别，这种锌卟啉可以与氨基酸酯形成1:1和1：2的两种加合物，客体分子的氨基首先与主体分子上氨基酸残基的羧基作用形成1：1的加合物，然后另一客体分子的氨基与锌卟啉的中央锌原子配位形成1：2的加合物，客体分子与主体分子上的氨基酸残基之间的库仑力作用以及主－客体之间的色散力作用可能是主体分子能识别客体分子的另外两种相互作用。     

C16H14SNF分子中不共面轭环上π轨道通过键的相互作用的研究

本文根据我们测定的C16H14SNF(1)和C16H16SNF(2)晶体结构数据,用MNDO2方法进行分子轨道研究,发现1和2的几何构型虽然相近,但其分子轨道中的原子轨道组成有着质的差异:在HOMO和临近HOMO的占据分子轨道中,2的两个苯环的π轨道彼此没有相互作用;1的两个夹角为80°的苯环的π轨道同时出现在一个分子轨道中,彼此通过C=N-键导通,显示出相互作用,与实验观察到的核磁共振谱一致.     

附子中双酯型乌头碱类成分水解减毒机理的密度泛函理论研究

采用密度泛函理论B3LYP/6-31G*方法,对附子中的9种乌头碱类成分进行了量子化学理论研究,讨论了该类生物碱的结构和毒性的关系.结果表明,由于水解过程中C(8)和C(14)上基团的变化影响了分子的构型、电荷分布、前线分子轨道等性质,使分子与受体之间的作用减弱,毒性降低,生物碱分子的正电区域是发生作用的活性中心.     

Hydrothermal Synthesis,Crystal Structure,Spectrum Properties and Quantum Chemical Calculation of a Trinuclear Copper（Ⅱ） Complex with 3-（Pyridin-2-yl）-1,2,4-triazole

A three-dimensional framework copper(Ⅱ) coordination polymer with copper carbonate basic and 3-(pyridin-2-yl)-1,2,4-triazole (Hpt) has been hydrothemally synthesized.The complex (2,C14 H10 CuN8 ·3H2 O) crystallizes in tetragonal,space group P4 2 /n,a=2.08581(12),b=2.08581(12),c=0.72331(4) nm,M r=761.73,V=3.1468(3) nm 3,Dc=1.608 g/cm 3,Z=4,F(000)=1552,GOOF=1.07,R=0.0515 and wR=0.1689.Every asymmetric unit molecular structure of the complex is composed with one copper ion,one and half water molecules and two Hpt molecules.Each copper ion is coordinated with five nitrogen atoms from four Hpt molecules,forming a distorted square pyramidal geometry.The fluorescence spectrum analysis shows that the title complex at room temperature exhibits intense photoluminescence with maximum emission at 450 nm.The quantum chemistry calculation study on the complex has been performed.The stability,some frontier molecular orbital energies and composition characteristics of some frontier molecular orbitals of the complex have been investigated.     

胶体铜催化丙烯腈水合的高选择性及其活性中心结构的研究

研究了胶体铜催化丙烯腈水合制丙烯酰胺的高选择性与活性中心结构的关系. 在聚乙烯吡咯烷酮(PVP)保护下, 用肼和氢氧化钠混合液还原CuCl2制得胶体铜, 用其催化丙烯腈水合反应, 选择性达到100％, 产生高选择性的原因如下: (1) 胶体铜的活性中心不是胶粒表面的点缺陷, 而是胶体铜颗粒表面的位错端点. (2) 由于胶体铜具有高硬度和高强度的力学特性, 保证了活性中心结构的稳定性; 胶体铜颗粒的平均粒径(45 nm)超过晶粒的特征长度, 进一步保证了活性中心的稳定性.     

Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond

The copper-sulfur bond that binds cysteinate to the metal center is a key factor in the spectroscopy of blue copper proteins. We present theoretical calculations describing the electronically excited states of small molecules, including CuSH, CuSCH(3), (CH(3))(2)SCuSH, (imidazole)-CuSH, and (imidazole)(2)-CuSH, derived from the active site of blue copper proteins that contain the copper-sulfur bond in order to identify small molecular systems that have electronic structure that is analogous to the active site of the proteins. Both neutral and cationic forms are studied since these represent the reduced and oxidized forms of the protein, respectively. For CuSH and CuSH(+), excitation energies from time-dependent density functional theory with the B97-1 exchange-correlation functional agree well with the available experimental data and multireference configuration interaction calculations. For the positive ions, the singly occupied molecular orbital is formed from an antibonding combination of a 3d orbital on copper and a 3p(π) orbital on sulfur, which is analogous to the protein. This leads several of the molecules to have qualitatively similar electronic spectra to the proteins. For the neutral molecules, changes in the nature of the low lying virtual orbitals leads the predicted electronic spectra to vary substantially between the different molecules. In particular, addition of a ligand bonded directly to copper results in the low-lying excited states observed in CuSH and CuSCH(3) to be absent or shifted to higher energies.     

Copper(II) complex of the chelating agent EDTA bis(tyrosine)

The synthesis technique is given and the results of X-ray study of a copper(II) compound, Cu(O₁₂N₄C₂₈H₃₀)·7H₂O, are reported. The structure is molecular and the copper atom is coordinated by a distorted octahedron exhibiting a Jahn-Teller effect. The Cu-O(carbonyl) bond is 0.31 Å longer than the axial carboxylate to copper bonds.     

硅基分子印迹技术制备铜离子选择电极

以3-（2-氧基乙基氨基）丽基三甲氧基硅烷作为功能分子,铜离子为模板,将分子印迹技术与溶胶凝胶技术相结合,制备了铜离子选择电极,探讨了电极的响应机理．该电极对铜离子有较好的能斯特响应特性,其线性响应范围为5．00×10^-2～3．98×10^-6mol·L^-1,斜率为31．5mV／pC（-logc）,检出限为1．00×10^-6mol·L^-1．同时该电极显示了较好的选择性,重现性和稳定性．     

Spectroscopic and density functional studies of the red copper site in nitrosocyanin: role of the protein in determining active site geometric and electronic structure

The electronic structure of the red copper site in nitrosocyanin is defined relative to that of the well understood blue copper site of plastocyanin by using low-temperature absorption, circular dichroism, magnetic circular dichroism, resonance Raman, EPR and X-ray absorption spectroscopies, combined with DFT calculations. These studies indicate that the principal electronic structure change in the red copper site is the sigma rather than the pi donor interaction of the cysteine sulfur with the Cu 3d(x2-y2) redox active molecular orbital (RAMO). Further, MCD data show that there is an increase in ligand field strength due to an increase in coordination number, whereas resonance Raman spectra indicate a weaker Cu-S bond. The latter is supported by the S K-edge data, which demonstrate a less covalent thiolate interaction with the RAMO of nitrosocyanin at 20% relative to plastocyanin at 38%. EXAFS results give a longer Cu-S(Cys) bond distance in nitrosocyanin (2.28 A) compared to plastocyanin (2.08 A) and also show a large change in structure with reduction of the red copper site. The red copper site is the only presently known blue copper-related site with an exogenous water coordinated to the copper. Density functional calculations reproduce the experimental properties and are used to determine the specific protein structure contributions to exogenous ligand binding in red copper. The relative orientation of the CuNNS and the CuSC(beta) planes (determined by the protein sequence) is found to be key in generating an exchangeable coordination position at the red copper active site. The exogenous water ligation at the red copper active site greatly increases the reorganization energy (by approximately 1.0 eV) relative to that of the blue copper protein site, making the red site unfavorable for fast outer-sphere electron transfer, while providing an exchangeable coordination position for inner-sphere electron transfer.     

Halogen-substituted salicylhydroximate copper(II) metallacrowns: from synthesis and structures to novel applications

New halogen-substituted salicylhydroximate copper(II) metallacrowns were synthesized from Cu(OAc)₂ and the corresponding salicylhydroxamic acids. Their molecular structure was determined by single crystal X-ray diffraction. The compounds obtained represent the first members of the metallacrown family that can be used as components of active initiators for the photopolymerization of oligo-carbonate dimethacrylate by visible light.     

Solvation of Copper(II) Ions in Liquid Ammonia

X-ray absorption fine structure (XAFS) measurements have been performed at -50 degrees C on a 0.4 mol dm(-)(3) copper(II) nitrate solution in liquid ammonia. Extended X-ray absorption fine structure (EXAFS) spectroscopy was used to determine the coordination number and bond distances for the solvated copper(II) ion in solution. The equatorial ammonia nitrogens are located 2.00 ? from the copper and the axial nitrogen 2.19 ? from the copper. However, it was not possible from the EXAFS analysis alone to conclude whether there was one or two axial nitrogens. Therefore, X-ray absorption near-edge structure (XANES) spectroscopy was combined with discrete variational Xalpha (DV-Xalpha) molecular orbital calculations for a series of five- and six-coordinated models to determine the coordination number and the geometry. The experimental XANES spectrum was best reproduced by a model where the copper(II) ion is pentacoordinated in liquid ammonia in a square pyramidal geometry with the copper(II) ion lifted above the average nitrogen plane.     

改性纤维素的制备及分光光度法对Cu~(2+)吸附研究

针对日益严重的铜离子污染问题,以化学浆纤维素为原料,通过氨基酸接枝修饰2,2,6,6-四甲基哌啶氧自由基(TEMPO)氧化体系氧化的纤维素,制备出一种新型吸附剂,并采用灵敏简便的分光光度法研究改性对铜离子的吸附效果。结果表明,氨基酸修饰纤维素(AMC)与TEMPO氧化纤维素(TOC)相比,对铜离子的吸附效果有不同程度的提升,其中组氨酸改性的吸附效果最好,低浓度时吸附率可以高达97%。随着浓度增大,吸附率下降,但是吸附量增大,当吸附200 mg/L的Cu2+溶液时,吸附量可达47 mg/g。此外,研究了不同条件下AMC对Cu2+的吸附情况,包括AMC投加量、初始浓度、pH值等。结果表明,吸附过程的吸附模型符合Langmuir等温模型,吸附动力学可以用准二级吸附动力学方程拟合。     

双核铜配合物的合成与晶体结构

室温下,在吡啶-2-甲酸存在下,过氧化苯甲酰和金属铜粉经过氧化加成反应生成双核铜(Ⅱ)配合物,［Cu(C₆H₅NO₂)(C₆H₅COO)₂］₂,X-射线单晶结构分析确定了配合物的分子和晶体结构,晶体属单斜晶系,空间群为P2₁/n,晶胞参数如下：a=10.423(5)?, b=10.511(3)?, c=16.896(11)?, β=99.37(5)°,V=1826.4?^{3。中心铜离子由桥式双齿苯甲酸根和吡啶-2-甲酸配位形成二聚双核配合物,同时通过红外光谱和热分析表征了配合物的性质。}