Space Group of Aquaimidazolemaleatozinc, [（H2O）（C3H4N2）（O2CCH=CHCO2Zn）]n

The space group of [(H2O)(C3H4N2)(O2CCH=CHCO2Zn)]n, which was originally described in the acentric Pc space group (Liu et al., Chin. J. Struct. Chem 2004, 23, 160～163),is re-described in the centric P21/c space group.     

Crystal Structure and Thermal Decomposition Mechanism of [K（DNP）（H2O）0.5]n

Introduction As developing high-energy, low toxicity and envi-ronment friendly primary explosive has been becoming a new and important investigation field, much attention has been paid to nitrogen-rich potassium coordination compounds for the sake of their low toxicity and little pollutions.1-11 In order to make good use of potassium compounds, the reaction of 2,4-dinitrophenol (DNP) and potassium hydroxide was designed, and the title compound potassium 2,4-dinitrophenate (KDNP) was obtained…     

Synthesis and Crystal Structure of a Two-dimensional Coordination Polymer [Cd（dym）（H2O）2（H2O）]n with Cd6 Hexagonal Macrometallocycle

1 INTRODUCTION The investigation of coordination polymers has rapidly been expanded in last decade owing to their potential applications such as catalysis, molecular absorption, non-linear and magnetic materials. Among the varieties of such coordination polymers, the po- lymers of cadmium with dicarboxylates having fas- cinating structural topologies and good photolumi- nescence constitute a new family. Many reports are concerned about cadmium dicarboxylate polymers with 1D helix structu…     

Synthesis and Crystal Structure of Cadmium（Ⅱ） Complex [Cd（H2O）（CH3OC6H4COO）2]n

1 INTRODUCTION Cadmium (Ⅱ) complexes have been exten- sively studied from both chemical and structural views, mainly due to the capability of cadmium (Ⅱ) (shared by most d10 metal ions) to adopt different modes of coordination determined by the consideration of size, as well as electrostatic and covalent bonding forces[1]. And the field of coordination polymers has witnessed tremendous growth over the last decade[2]. Many coordination polymeric networks have been shown to posses intere…     

Synthesis and Crystal Structure of a Novel Two-dimensional Layered Polymer [Zn（μ-O2CCH=CHCO2）（C3H4N2）（H2O）]n

1 INTRODUCTION More than 200 known metalloenzymes of a wide variety of types have been shown to contain zinc centers at their active sites (such as hydrolases, ligases and anhydrases)[1～3]. The active zinc centers in biological systems are usually surro…     

Synthesis and Structural Characterization of [Mn（phen）2（H2O）2]（OAc）2.6H2O

1 INTRODUCTION Water oxidation to oxygen gas by photo- synthetic apparatus of green plants and cyano- bacteria is the origin of this gas in the atmosphere. The water oxidation center is a tetranuclear, oxide- bridged manganese cluster with O,N-based peri- pheral ligation by amino acid side-chain group[1, 2]. The binding of aqua to the Mn site may be impor- tant to the oxidation of aqua for producing dioxygen. 1,10-Phenanthroline has been adopted to simulate coordination sphere of manga…     

Hydrothermal Synthesis and Crystal Structure of a Three-dimensional Compound {Mn（H2O）4（VO）2（PO4）2}n

1 INTRODUCTION Current research interest is focused on the designof structures built up from octahedral and tetrahedralbuilding blocks[1]. During the wide investigations intransition-metal phosphates for many years, a num-ber of new mixed transition-metal phosphates havebeen reported[2]. A great number of manganese phos-phates were largely discovered as minerals[1]. On theother hand, many vanadium phosphates have alsobeen prepared recently partly because of their poten-tial applications …     

Preparation, Crystal Structure and Thermal Behaviour of a One-dimensional Coordination Polymer [Mn（m-CPOAH）2（H2O）2]n

1 INTRODUCTION Supramolecular chemistry of manganese(II) car- boxylate coordination polymers has been inten- sively studied in recent years, within which ligand design is an important aspect in adjusting the coordi- nation framework and functionalities of the complexes formed[1～4]. Carboxyphenoxyacetic acids (CPOAH2), which have been known to show biological activities and are widely used in agriculture, are a family of multidentate flexible ligands with versatile binding abilities. …     

Theoretical Studies on the Intermonomer Interaction of F~-·(H_2O)_n (n = 1, 2)

1 INTRODUCTION Hydrogen bond plays an important role in the fields of physics, biology and chemistry. It has cap- tured the interest of chemists for a long time and reports about its theory and experiment have been well represented[1～6]. Concerning its theoretical inves- tigations, most of the emphases are placed on the weak interaction energy of intramolecular hydrogen bond. But studies on its spectrum behavior are rela- tively rare. These years spectrum behavior led by hydrogen bond h…     

乙醇-水分子团簇C2H5OH(H2O)n (n=1-9)稳定结构的量子化学研究

采用密度泛函理论B3LYP方法, 在B3LYP/6-311++G(2d,2p)//B3LYP/6-311++G(d,p)基组水平上对乙醇-水分子团簇(C₂H₅OH(H₂O)_n (n=1-9))的各种性质进行研究, 如: 优化的几何构型、结构参数、氢键、结合能、平均氢键强度、自然键轨道(NBO)电荷分布、团簇的生长规律等. 结果表明, 从二维(2-D)环状结构到三维(3-D)笼状结构的过渡出现在n=5的乙醇-水分子团簇中. 此外, 利用团簇结合能的二阶差分、形成能、能隙等性质, 发现在n=6时乙醇-水分子团簇的最低能量结构稳定性较好, 可能为幻数结构. 最后, 为了进一步探讨氢键本质, 将C₂H₅OH(H₂O)_n (n=2-9)最低能量结构的各种性质与纯水分子团簇(H₂O)_n (n=3-10)比较, 结果表明前者与后者中的水分子之间氢键相似.     

Pdn(n=2～13)团簇的密度泛函理论研究

采用密度泛函理论B3LYP方法计算并讨论钯原子团簇Pdn(n=2～13)结构模型.通过对钯原子团簇进行几何构型优化和振动频率计算,找出团簇总能量最低的同分异构体.由于Jahn-Teller效应的存在,团簇的最稳定结构采取对称性较低的几何构型.在钯原子数相同时,往往存在多个能量极为相近的稳定构型.单位原子平均静态极化率呈奇偶变化.     

2-羟基吡啶与水氢键作用的理论研究

本文采用量子化学的Hatree-Fock方法和密度泛函理论(DFT)的B3LYP方法,在6-31G(d)水平上,研究了2-羟基吡啶分子(Hy)及其酮式互变异构体2(1H)-吡啶酮(Py)与水的相互作用。考察它们之间在形成Hy…H2O,Py…H2O,Hy…Hy,Py…Py和Hy…Py等复合物前后的能量变化和分子结构参数变化特点。计算结果表明,在这些复合物中都形成了较强的氢键作用,在水合物中,Py与水形成复合物时能量降低较多,与实验结果一致。经过零点振动能(ZPVE)和基组叠加误差(BSSE)校正后的复合物离解能分别为38.3,40.8,73.0,82.7和71.1 kJ/mol(B3LYP/6-31G(d)),水合物的离解能远小于二聚体复合物,而酮式结构的二聚体的离解能最大。     

Energetic Ordering of Hydrogen Bond Strengths in Methanol-Water Clusters: Insights via Molecular Tailoring Approach

In this work, we examine the strength of various types of individual hydrogen bond (HB) in mixed methanol-water M_nW_m, (n+m=2 to 7) clusters, with an aim to understand the relative order of their strength, using our recently proposed molecular tailoring-based approach (MTA). Among all the types of HB, it is observed that the O_M−H…O_W HBs are the strongest (6.9 to 12.4 kcal mol⁻¹). The next ones are O_M−H…O_M HBs (6.5 to 11.6 kcal mol⁻¹). The O_W−H…O_W (0.2 to 10.9 kcal mol⁻¹) and O_W−H…O_M HBs (0.3 to 10.3 kcal mol⁻¹) are the weakest ones. This energetic ordering of HBs is seen to be different from the respective HB energies in the dimer i. e., O_M−H…O_M (5.0 to 6.0 kcal mol⁻¹)>O_W−H…O_M (1.5 to 6.0 kcal mol⁻¹)>O_M−H…O_W (3.8 to 5.6 kcal mol⁻¹)>O_W−H…O_W (1.2 to 5.0 kcal mol⁻¹). The plausible reason for the difference in the HB energy ordering may be attributed to the increase or decrease in HB strengths due to the formation of cooperative or anti-cooperative HB networks. For instance, the cooperativity contribution towards the different types of HB follows: O_M−H…O_W (2.4 to 8.6 kcal mol⁻¹)>O_M−H…O_M (1.3 to 6.3 kcal mol⁻¹)>O_W−H…O_W (−1.0 to 6.5 kcal mol⁻¹)>O_W−H…O_M (−1.2 to 5.3 kcal mol⁻¹). This ordering of cooperativity contribution is similar to the HB energy ordering obtained by the MTA-based method. It is emphasized here that, the interplay between the cooperative and anti-cooperative contributions are indispensable for the correct energetic ordering of these HBs.     

理论研究V2O6-的结构和电子性质

The geometrical and electronic properties of the anionic and neutral V2O6 clusters were studied with the spin unrestricted hybrid density functional B3LYP method. The calculated ground states of both clusters are different from the previous theoretical results. The ground state of V2O6- is found to be a doublet with C2v symmetry, while a doublet with D2h symmetry was previously obtained by Vyboishchikov and Sauer. For neutral V2O6, the ground state is an open-shell singlet with D2h symmetry whose energy is very close to that of the triplet state. In contrast, a closed-shell singlet with D2h symmetry was obtained by Vyboishchikov and Sauer, and Calatayud et al. found a triplet ground state with Cs symmetry. Moreover,the calculated adiabatic and vertical detachment energies of the anion cluster are in much better agreement with the experimental results of photoelectron spectroscopy than previous theoretical values.     

(H2O)2和(HCl)2非线性光学性质的从头计算研究

用MP2方法及aug-cc-pVDZ,aug-cc-pVDZ+BF,aug-cc-pVTZ和aug-cc-pVTZ+BF基组对(H2O)2和(HCl)2超分子的静态偶极矩μ0,极化率α0及第一超极化率β0进行计算.采用Counterpoise方法消除基组的重叠误差(BSSE),得到上述物理性质的分子间相互作用的贡献,在此基础上研究了其中新的长程π型氢键的效应.     

Theoretical study of the structure, stability, and infrared spectra of hydrogen-bonded complexes of N-nitrosodiethanolamine (NDELA) with water molecules

A theoretical study of the interaction between the N-nitrosodiethanolamine (NDELA) molecule and one to five water molecules was performed at the B3LYP level using a large polarized basis set. The calculated complexation energies (corrected for BSSE and ZPVE) of NDELA with one, two, three, four, and five water molecules are ?4.62 kcal/mol, ?9.83 kcal/mol, ?15.29 kcal/mol, ?21.60 kcal/mol, and ?25.10 kcal/mol respectively at the B3LYP/6-311++G** level. In all complexes studied, there are red shifts in the vibrational frequencies of the O-Hs of NDELA and water molecules along with increases in the corresponding IR intensities.     

Ab initio investigation of water clusters (H2O)n (n = 2–34)

Various properties of typical structures of water clusters in the n = 2–34 size regime with the change of cluster size have been systematically explored. Full optimizations are carried out for the structures presented in this article at the Hartree–Fock (HF) level using the 6‐31G(d) basis set by taking into account the positions of all atoms within the cluster. The influence of the HF level on the results has been reflected by the comparison between the binding energies of (H₂O)_n (n = 2–6, 8, 11, 13, 20) calculated at the HF level and those obtained from high‐level ab initio calculations at the second‐order Møller–Plesset (MP2) perturbation theory and the coupled cluster method including singles and doubles with perturbative triples (CCSD(T)) levels. HF is inaccurate when compared with MP2 and CCSD(T), but it is more practical and allows us to study larger systems. The computed properties characterizing water clusters (H₂O)_n (n = 2–34) include optimal structures, structural parameters, binding energies, hydrogen bonds, charge distributions, dipole moments, and so on. When the cluster size increases, trends of the above various properties have been presented to provide important reference for understanding and describing the nature of the hydrogen bond. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

富勒烯C36及其衍生物C36H2n的量子化学研究

应用密度泛函B₃LYP方法和从头算(abinitio)HF方法,在3-21G理论水平上,对具有C_2v,D_2d,D_3h和D_6h对称性的四种C₃₆异构体以及在保持D_2d,D_3h和D_6h对称性条件下形成的不同氢化物进行了量子化学计算,研究了它们在不同量子态时的分子几何构型和电子结构.结果表明,电子相关效应在C₃₆簇化合物的电子结构中起着重要作用.它们最稳定的结构是C₃₆的³A_2u量子态D_6h异构体,而C₃₆的氢化物是在D_3h异构体的C₂位置等同碳原子上形成的¹A_1'量子态氢化物C₃₆H₁₂.