多体展形势函数在碳族元素原子族研究中的应用（Ⅳ）—Si9—Si16原子簇…

多体展开势能函数研究表明，Ｓｉ４－Ｓｉ１６原子簇分子间的结构衍生关系：依次增加一个二配位或三配位的表面原子，分子表面被四元蝶形环Ｓｉ４（Ｄ２ｄ）所覆盖；Ｓｉｎ（ｎ＝５－１６）结构中多含有Ｓｉ５（Ｄ３ｈ）、Ｓｉ６（Ｄ２ｄ）区域结构单元，笼状Ｓｉ１０及Ｓｉ１６的表面原子均为三配位或三配位以上，预计Ｓｉ５、Ｓｉ６、Ｓｉ１０及ｓｉ１６是硅原子簇碎片化产物分布中丰度较高的序列；在这一范围内的分子结构呈与晶体     

P6（D6h）和P12（D6h的从头算研究

利用Ｇａｕｓｓｉａｎ－９２从头算程序，在６－３１Ｇ￣＊基组下优化Ｐ_６（Ｄ_６ｈ）分子和Ｐ_（１２）（Ｄ_（６ｈ））原子簇，并进行了振动频率的计算．得到２Ｐ_６（Ｄ_（６ｈ））→Ｐ_（１２）（Ｄ_（６ｈ））总能量的相对值，即△Ｅ＝Ｅ_Ｐ_（１２_（Ｄ_（６ｈ））－２ＥＰ_６（Ｄ_（６ｈ））＝－１．１９７ｅＶ．　Ｐ_（１２）（Ｄ_（６ｈ））原子簇较２Ｐ_６（Ｄ_（６ｈ））分子在热力学上更为稳定。基组下，Ｈｐ＝ＨＰ优化的Ｐ＝Ｐ双键键长为０．２００５ｎｍ，Ｈ２Ｐ─ＰＨ２优化的Ｐ─Ｐ单键键长为０．２２１４ｎｍ，显然，Ｐ６（Ｄ６ｈ）分子中的键长比优化双键长０．００９１ｎｍ，比优化单键短０．０１１８ｎｍ，对于Ｐ６（Ｄ６ｈ）分子而言，其键长介于单、双键之间且相等。Ｐ６分子前线轨道的第３９条分子轨道形式估算为：联系人及第一作者：冯健男，男，２５岁，博士研究生。     

Pb_n(n=2～30)团簇结构及铅晶体表面过程的计算机模拟

本文作者近年来采用 Ｍｕｒｒｅｌｌ等提出的有效的二体加三体展开势能函数（ｅｆｆｅｃｔｉｖｅｔｗｏ－ｐｌｕｓ－ｔｈｒｅｅ－ｂｏｄｙ ｐｏｔｅｎｔｉａｌ ｅｎｅｒｇｙ ｆｕｎｃｔｉｏｎ）研究过 Ｓｉｎ［１］、Ｇｅｎ［２］及 Ｘｎ［３］（Ｘ＝Ｌｉ,Ｎａ,Ｋ等）等微团簇的结构和相对稳定性,并提出笼状锗结构预测［４］。本文试图将这一具有简单解析形式的势能函数模型推广到Ｐｂｎ团簇及面心立方晶体铅表面过程的计算机模拟。对Ｐｂｎ这样的重金属团簇,从头计算结果还仅限于 Ｐｂ２、Ｐｂ３和 Ｐｂ４,实验中观察到 Ｐｂ７结构中…     

吡啶－2，6－二甲酸钪配合物［Sc（HDPA）（DPA）（H_2O）_2］·5

在水溶液中合成了吡啶－２，６－二甲酸抗配合物的晶体，元素分析结果表明，可用Ｓｃ（ＨＤＰＡ）（ＤＰＡ）·７Ｈ＿２Ｏ表示，用Ｘ射线衍射方法测定了配合物的单晶结构，其结构式为［Ｓｃ（ＨＤＰＡ）（ＤＰＡ）（Ｈ２Ｏ）２］·５Ｈ２Ｏ。晶体属正交晶系，空间群为Ｐｎ２１ａ。晶胞参数如下：ａ＝１．０１６９（２）ｎｍ，ｂ＝１．０１７２（２）ｎｍ，ｃ＝２．０２５４（４）ｎｍ；Ｖ＝２．０９５（１）ｎｍ３，Ｚ＝４，Ｄ＝１．５９ｇ／ｃｍ３。抗离子的配位数为８，其配位多面体为三角十二面体。     

Ce0.5Zr0.5O2固溶体的原位拉曼光谱

控制合成条件以湿化学法制备了Ｃｅ－Ｚｒ－Ｏ（Ｃｅ）／ｎ（Ｚｒ）＝１固溶体,ＸＲＤ结果证实催化剂前体经９２３Ｋ焙烧后可获得立方相Ｃｅ０．５Ｚｒ０．５Ｏ２固溶体,ＴＥ倒固溶体颗粒大小均一、分散、呈纤毛状、在氧化和还原气氛条件下分别对固溶体进行了原位拉曼光谱研究,结果表明,除４５０－４７０ｃｍ＾－１处出现而心立方晶格Ｆ２ｇ拉曼地应的强拉曼谱峰外,２９０－３２０ｃｍ＾－１,５７－６２０ｃｍ＾－１,７７０－     

离子对高效液相色谱法分析注射用新灭菌

建立了离子对高效液相色谱法分离与测定复方制剂（新灭菌）中的羟氨苄青霉素及氟氯青霉素含量法。采用Ｃ８．１０μｍ，４．６×２００ｍｍ柱（大连化物所Ｓｐｈｅｒｉｓｏｒｂ），以含１．４％十六烷基三甲基溴化铵的ｐＨ６．５磷酸盐缓冲液－乙腈（６８＋３２）为流动相，在紫外检测器２５４ｎｍ波长处检测，线性范围为０．２５～２ｍｇ／ｍＬ，ｒ＝０．９９９９（ｎ＝５），羟氨苄青霉素及氟氯青霉素平均回收率分别为９９．５％及１００．７％（ｎ＝５）。精密度：羟氨苄青霉素及氟氯青霉素日内（４ｈ）平均ＲＳＤ（相对标准偏差）均为０．８％（ｎ＝１５），日间（２ｈ）平均ＲＳＤ分别为０．６％和０．７％（ｎ＝３）。     

含质子柠檬酸氧钒（V）配合物中间体的合成和晶体结构

合成了含质子柠檬酸氧钒（Ｖ）配合物中间体ＮａＫ３［ＶＯ２（Ｈｃｉｔ）］２·７Ｈ２Ｏ，用红外光谱和Ｘ射线衍射进行了结构表征。结果表明：晶体属单斜晶系，Ｐ２１／ｎ空间群。晶胞参数ａ＝１．１２５８（２）ｎｍ，ｂ＝１．５７７４（３）ｎｍ，ｃ＝１６５５９（１）ｎｍ，β＝９８．５６８（９）°，Ｖ＝２．９０８（１）ｎｍ＾３，Ｚ＝４，Ｄｃ＝１．８５１ｇ·ｃｍ＾－３，Ｆ（０００）＝１６４０，μ（Ｃｕ Ｋα）＝１０４     

原子簇P12（D3d）的理论研究

利用Ｇａｕｓｓｉａｎ－９２程序在６－３１Ｇ基组下优化Ｐ１２（Ｄ３ｄ）构型，研究了３Ｐ４（Ｔｄ）→Ｐ１２（Ｄ３ｄ）的相对能量，计算结果为△Ｅ＝Ｅｐ１２（Ｄ３ｄ）－３Ｅｐ４（Ｔｄ）＝－７９．８４４ｋＪ／ｍｏｌ，优化Ｐ１２（Ｄ３ｄ）获得的Ｐ－Ｐ键键长接近于实验测得的Ｐ－Ｐ单键键长，并进一步在该基组下计算了Ｐ１２（Ｄ３ｄ）原子簇的振动频率，得到的全部为正频率，表明原子簇Ｐ１２的Ｄ３ｄ构型是位能面上的稳定点     

非对称Schiff碱过渡金属配合物模拟酶催化烯烃环氧化（I）

研究了温和条件下以亚碘酰苯为氧源，非对称性的和对称性的Ｍｎ（Ⅲ）Ｓｃｈｉｆｆ碱配合物「Ｍｎ（Ⅲ）（ＣＢＰ－ｐｈｅｎ－Ｘｓａｌ）Ｃｌ，Ｘ＝Ｈ，Ｃｌ，Ｂｒ，Ｎｏ２，Ｃｈ３，ＯＣＨ３」和「Ｍｎ（Ⅲ）（ＣＢＰ－Ｒ－ＣＢＰ）Ｙ，Ｒ＝ＣＨ２ＣＨ２－，－ＣＨ（ＣＨ３）ＣＨ２－，－Ｃ６Ｈ４－；Ｙ＝Ｃｌ，ＯＣＨ３」催化非官能性烯烃苯乙烯，环己烯和α甲基苯乙烯的环氧化反应，结果表明，非对称配合物Ｍｎ（Ⅲ）的电子结合能     

MonC4n(n＝1－4)原子簇的合成和表征

Ｍｏ_ｎＣ_（４ｎ）（ｎ＝１－４）原子簇的合成和表征美国奥克里季实验室的ＣｈａｒｇｍｉｎｇＪｉｎ等化学家最近对Ｍｏ（ＣＯ）６蒸气激光（ＸｅＣｌ激光，波长３０８ｎｍ）光解生成的超细粒子进行了结构鉴定和性质分析。这些粒子直径小于１μｍ，利用负离子质谱可确定...     

Theoretical study on the small clusters of LiH, NaH, BeH(2), and MgH(2)

High-level ab initio molecular orbital theory is used to calculate the geometries, vibrational frequencies, atomic charges, and binding energies of the small clusters (LiH)(n), (NaH)(n), (BeH(2))(n), and (MgH(2))(n) (n = 1-4). For (LiH)(n) and (NaH)(n), there are planar cyclic structures when n = 2, 3. We have found the cubic structure T(d) in addition to the planar cyclic D(4)(h) when n = 4. The D(4)(h) is less stable than the T(d) geometry. For (BeH(2))(n) and (MgH(2))(n), when n = 3, there are three kinds of structures: chain C(2)(v), planar cyclic D(3)(h), and hat-like C(2)(v). The C(2)(v) geometry is more stable than the others. When n = 4, there are four kinds of structures: chain D(2)(h), cubic T(d), string-like C(2), and cubic transformation C(1). The most stable compounds in the families of (LiH)(n), (NaH)(n), (BeH(2))(n), and (MgH(2))(n) are cubic T(d), cubic T(d), chain D(2)(h), and string-like C(2) geometries, respectively, when n = 4. Calculated binding energies range from -24 to -37 kcal/mol for (LiH)(n) and --19 to -30 kcal/mol for (NaH)(n), (BeH(2))(n), and (MgH(2))(n). The hydrogen atoms in hydride clusters always have negative charges. The atomic charges of planar cyclic structures are weaker than those of cubic structures, and there is a tendency of reducing along with the increase of the cluster size. The vibrational frequencies of planar cyclic structures have consistent tendency, too. It indicates that the bond distance increases with the ionic character of the bond.     

Enhanced stability by three-dimensional aromaticity of endohedrally doped clusters X(10)M(0/-) with X = Ge, Sn, Pb and M = Cu, Ag, Au

The group 14 clusters encapsulated by coinage metals in neutral and anionic states X(10)M(0/-) (X = Ge, Sn, Pb and M = Cu, Ag, Au) are investigated using quantum chemical calculations with the DFT/B3LYP functional and coupled-cluster CCSD(T) theory. Addition of transition metals into the empty cages forms high symmetry endohedral structures, except for Ge(10)Ag(0/-). In agreement with experiments available for X(10)Cu, the D(4d) global minima of the anions are calculated to be magic clusters with large frontier orbital gaps, high vertical and adiabatic detachment energies, and large embedding energies and binding energies as compared to those of the empty cages X(10)(2-). The enhanced stability of these magic clusters can be rationalized by the three-dimensional aromaticity.     

Structure, energetics, and reactions of alkali tetramers

Electronic structure calculations have been carried out for all possible alkali tetramers that can be formed from X(2) + X(2) → X(2)X(2), X(2) + Y(2) → X(2)Y(2), and XY + XY → X(2)Y(2) alkali dimer association reactions. Vibrationally stable rhombic (D(2h)) and planar (C(s)) structures are found for all possible tetramers formed from the alkali metals, Li to Cs. All tetramer formation reactions (from ground state singlet homonuclear or heteronuclear dimers) are found to be exothermic with binding energies ranging from 6282 cm(-1) for Li(2)Li(2) to 1985 cm(-1) for Cs(2)Cs(2). Extensive calculations, carried out at long-range for several reactant pairs, indicate that there are barrier-less pathways for the formation of tetramers from dimer association reactions. At low temperatures, direct formation of tetramers is unlikely, owing to the large exothermicity associated with these association reactions, but atom exchange reactions (X(2) + Y(2) ? XY + XY) are possible for some species.     

(HAINH)_n(n=1～6)簇的结构、红外光谱和热力学性质的研究

用自洽场理论(HF)和密度泛函理论(DET)的B3LYP方法,在6-31G~μ水平上研究了HAINH的低聚物(HAINH)_n(n=1～6)簇的几何构型、电子结构、红外光谱和化学热力学性质,并比较了(HAINH)_n和(CIAINH)_n两种低聚物对应结构中化学键强弱,分析了引起(AIN)_n骨架结构发生变化的原因.结果表明,(HAINH)_n簇的基态结构为C_8(n=1),D_(2h)(n=2),D_(3h)(n=3),T_d(n=4),C_s(n=5)和D_(3d)(n=6)对称点群.HAINH基态结构中,AI-N键是三重键.在D_(2h)(n=2)和D_(3h)(n=3)结构中,所有AI-N键均为二重键.在Td(n=4)和D_(3d)(n=6)中,AI-N键为正常单键,而在C_s(n=5)结构中含有三种AI-N键:单键、双键和混合键.振动频率计算表明,结构a～f均为基态稳定结构.热力学计算给出的稳定性顺序为:f>d>e>c>b>a.     

Theoretical study of Al(n) and Al(n)O (n = 2-10) clusters

The stable structures, energies, and electronic properties of neutral, cationic, and anionic clusters of Al(n) (n = 2-10) are studied systematically at the B3LYP/6-311G(2d) level. We find that our optimized structures of Al5(+), Al9(+), Al9(-), Al10, Al10(+), and Al10(-) clusters are more stable than the corresponding ones proposed in previous literature reports. For the studied neutral aluminum clusters, our results show that the stability has an odd/even alternation phenomenon. We also find that the Al3, Al7, Al7(+), and Al7(-) structures are more stable than their neighbors according to their binding energies. For Al7(+) with a special stability, the nucleus-independent chemical shifts and resonance energies are calculated to evaluate its aromaticity. In addition, we present results on hardness, ionization potential, and electron detachment energy. On the basis of the stable structures of the neutral Al(n) (n = 2-10) clusters, the Al(n)O (n = 2-10) clusters are further investigated at the B3LYP/6-311G(2d), and the lowest-energy structures are searched. The structures show that oxygen tends to either be absorbed at the surface of the aluminum clusters or be inserted between Al atoms to form an Al(n-1)OAl motif, of which the Al(n-1) part retains the stable structure of pure aluminum clusters.     

Amine-hydrogen halide complexes: experimental electric dipole moments and a theoretical decomposition of dipole moments and binding energies

The Stark effect has been observed in the rotational spectra of several gas-phase amine-hydrogen halide complexes and the following electric dipole moments have been determined: H(3)(15)N-H(35)Cl (4.05865 +/- 0.00095 D), (CH(3))(3)(15)N-H(35)Cl (7.128 +/- 0.012 D), H(3)(15)N-H(79)Br (4.2577 +/- 0.0022 D), and (CH(3))(3)(15)N-H(79)Br (8.397 +/- 0.014 D). Calculations of the binding energies and electric dipole moments for the full set of complexes R(n)()(CH(3))(3)(-)(n)()N-HX (n = 0-3; X = F, Cl, Br) at the MP2/aug-cc-pVDZ level are also reported. The block localized wave function (BLW) energy decomposition method has been used to partition the binding energies into contributions from electrostatic, exchange, distortion, polarization, and charge-transfer terms. Similarly, the calculated dipole moments have been decomposed into distortion, polarization, and charge-transfer components. The complexes studied range from hydrogen-bonded systems to proton-transferred ion pairs, and the total interaction energies vary from 7 to 17 kcal/mol across the series. The individual energy components show a much wider variation than this, but cancellation of terms accounts for the relatively narrow range of net binding energies. For both the hydrogen-bonded complexes and the proton-transferred ion pairs, the electrostatic and exchange terms have magnitudes that increase with the degree of proton transfer but are of opposite sign, leaving most of the net stabilization to arise from polarization and charge transfer. In all of the systems studied, the polarization terms contribute the most to the induced dipole moment, followed by smaller but still significant contributions from charge transfer. A significant contribution to the induced moment of the ion pairs also arises from distortion of the HX monomer.     

Electronic structure and thermochemical properties of silicon-doped lithium clusters Li(n)Si0/+, n = 1-8: new insights on their stability

A theoretical investigation on small silicon-doped lithium clusters Li(n)Si with n = 1-8, in both neutral and cationic states is performed using the high accuracy CCSD(T)/complete basis set (CBS) method. Location of the global minima is carried out using a stochastic search method and the growth pattern of the clusters emerges as follows: (i) the species Li(n)Si with n ≤ 6 are formed by directly binding one Li to a Si of the smaller cluster Li(n-1)Si, (ii) the structures tend to have an as high as possible symmetry and to maximize the coordination number of silicon. The first three-dimensional global minimum is found for Li(4)Si, and (iii) for Li(7)Si and Li(8)Si, the global minima are formed by capping Li atoms on triangular faces of Li(6)Si (O(h)). A maximum coordination number of silicon is found to be 6 for the global minima, and structures with higher coordination of silicon exist but are less stable. Heats of formation at 0 K (Δ(f)H(0)) and 298 K (Δ(f)H(298)), average binding energies (E(b)), adiabatic (AIE) and vertical (VIE) ionization energies, dissociation energies (D(e)), and second-order difference in total energy (Δ(2)E) of the clusters in both neutral and cationic states are calculated from the CCSD(T)/CBS energies and used to evaluate the relative stability of clusters. The species Li(4)Si, Li(6)Si, and Li(5)Si(+) are the more stable systems with large HOMO-LUMO gaps, E(b), and Δ(2)E. Their enhanced stability can be rationalized using a modified phenomenological shell model, which includes the effects of additional factors such as geometrical symmetry and coordination number of the dopant. The new model is subsequently applied with consistency to other impure clusters Li(n)X with X = B, Al, C, Si, Ge, and Sn.     

Electronic parameters of cation complexation by calixarene ionophores

The Gibbs energy of extraction experiments of ionophoric calixarenes with alkali metals from the literature have been correlated with electronic parameters of their “monomeric” structures calculated by AM1, PM3 and PM7 algorithms: energies of molecular orbitals and charge densities of oxygen and nitrogen atoms. We observed general correlations of the extraction constants with the charge on the carbonyl oxygen and specific correlations with MO-energy using the covalent term of the Klopman–Salem equation. The correlations for calixarenes with 5 and 6 phenolic units were very poor, and we attributed to the structural flexibility, which allow different optimized conformations for metal binding.     

Experimental and Theoretical Investigations of Structural Isomers of Dichalcogenoimidodiphosphinate Dimers: Dichalcogenides or Spirocyclic Contact Ion Pairs?

A synthetic protocol for the tert-butyl-substituted dichalcogenoimidodiphosphinates [Na(tmeda){(EPtBu(2))(2)N}] (3 a, E=S; 3 b, E=Se; 3 c, E=Te) has been developed. The one-electron oxidation of the sodium complexes [Na(tmeda){(EPR(2))(2)N}] with iodine produces a series of neutral dimers (EPR(2)NPR(2)E--)(2) (4 b, E=Se, R=iPr; 4 c, E=Te, R=iPr; 5 a, E=S, R=tBu; 5 b, E=Se, R=tBu; 5 c, E=Te, R=tBu). Attempts to prepare 4 a (E=S, R=iPr) in a similar manner produced a mixture including HN(SPiPr(2)). Compounds 4 b, 4 c and 5 a-c were characterised by multinuclear NMR spectra and by X-ray crystallography, which revealed two alternative structures for these dimeric molecules. The derivatives 4 b, 4 c, 5 a and 5 b exhibit acyclic structures with a central chalcogen-chalcogen linkage that is elongated by approximately 2 % (E=S), 6 % (E=Se) and 8 % (E=Te) compared to typical single-bond values. By contrast, 5 c adopts an unique spirocyclic contact ion-pair structure in which a [(TePtBu(2))(2)N](-) ion is Te,Te' chelated to an incipient [(TePtBu(2))(2)N](+) cyclic ion. DFT calculations of the relative energies of the two structural isomers indicate a trend towards increasing stability for the contact ion pair relative to the corresponding dichalcogenide on going from S to Se to Te for both the isopropyl and tert-butyl series. The two-electron oxidation of [Na(tmeda){(EPtBu(2))(2)N}] (E=S, Se, Te) with iodine produced the salts [(EPtBu(2))(2)N](+)X(-) (7 a, E=S, X=I(3); 7 b, E=Se, X=I; 7 c, E=Te, X=I), which were characterised by X-ray crystallography. Compound 7 a exists as a monomeric, ion-separated complex with [d(S--S)=2.084(2) A]; 7 b and 7 c are dimeric [d(Se--Se)=2.502(1) A; d(Te--Te)=2.884(1) A].     

Design and synthesis of a new class of nonmacrocyclic alkali metal host compounds

A new class of nonmacrocyclic metal ion hosts has been examined that features a polyspirocyclic framework that offers a 1,3,5-triaxial presentation of ligating centers. These compounds are easily synthesized and exploit stereoelectronic influences to preorganize the metal ion binding site. While compounds bearing oxygen substituents (X = OH, OMe) failed to show appreciable binding of alkali metals, the aminated host (X = NHBn) exhibitied strong binding with association constants (K(a)) greater than 10(7)-10(8) as measured by picrate extraction analysis.