烯烃聚合均相催化剂研究进展

均相催化剂产生于５０年代末期，但由于活性很低而末引起重视。８０年代初，由于发现ＭＡＯ具有良好的助催化能力而使均相催化剂得到了很大发展，涌现了多种催化体系，广泛地使α－烯烃及其衍生物立体选择性聚合，开辟了配位聚合研究的新领域，本文对均相催化剂的产生，发展及现状作了综述评述。     

An experimental and theoretical study of vibrational spectra of picolinamide, nicotinamide, and isonicotinamide

The molecular structures and vibrational spectra of the three isomers of pyridinecarboxamide (picolinamide, nicotinamide, isonicotinamide) were calculated with the Density Functional Theory (DFT) method using the B3LYP function and the 6-31++G(d,p), Z2PolX, Z3PolX basis sets. The calculations were performed by using the Gaussian98W packet program set. The total energy distributions (TED) of the vibrational modes of these molecules were calculated by using the Scale 2.0 program and the vibrational modes of the molecules were determined. The Scaled Quantum Mechanical (SQM) method was used in the scaling procedure. In the experimental part of the study, the solid phase FT-IR and Micro Raman spectra of the three isomers of pyridinecarboxamide have been recorded in the range of 4000-650 and 1200-100 cm⁻¹, respectively. The calculated wavenumbers were compared to the corresponding experimental values. As a result, the observed bands of the three isomers of pyridinecarboxamide were assigned with good accuracy.     

均相催化剂催化合成碳酸亚丙酯

分别就单组为催化剂和双组分催化剂对二氧化碳与环氧丙烷合成碳酸亚丙酯的催化活性进行了研究。实验结果表明，在单组分催化体系中，相转移催化剂，如十六烷基三甲基漠化按、四丁基演化铵对上述酯化反应具有较高的催化活性此外，盐酸羟胺、三苯基磷也有一定的催化活性；在双组分催化体系中，KI／PEG（聚乙二醇）体系具有很高的催化活性，能在较短时间内、较低的压力下高产率地得到碳酸亚丙酯，而某些金属盐、有机碱、季接盐的适当红合，也能有效地催化该反应。     

Preparation, structure and ethylene polymerization behavior of mixed-halide nickel(II) complexes and cobalt(II) complex containing imidazolium

Preparation of two imidazolium salts, two monomeric nickel(II) and one cobalt(II) complexes bearing imidazolium ligands is described, The solid-state structures of these compounds have determined by single-crystal X-ray diffraction. After activation with methylaluminoxane (MAO) the nickel complexes show moderate catalytic activities of up to 6 × 10⁵ g PE mol⁻¹Ni h⁻¹ for polymerization of ethylene. Catalytic activities, molecular weights have been investigated under the various reaction conditions.     

Towards the Design of New Materials: Regio- and Stereoselective (Cyclo-) Polymerization of 1-Alkynes and 1,6-Heptadiynes

Summary. The metathesis polymerization, respectively cyclopolymerization, of 1-alkynes and 1,6-heptadiynes using well-defined group VIA transition metal initiators is summarized. For purposes of comparison, selected quaternary catalytic systems used as alternatives as well as the properties of the resulting materials will be presented. Special consideration is given to the mechanistic advancements that have been made during the last decade, which allow the tailor-made synthesis of conjugated materials with interesting optical and electronic properties. E-mail: michael.r.buchmeiser@uibk.ac.at Received November 20, 2002; accepted November 21, 2002     

THE THEORETICAL STUDY OF ADSORPTION OF METAL IONS ON CHITOSAN

1. INTRODUCTION Chitin, the most abundant natural amino polysaccharide and estimated to be produced annually almost as much as cellulose, is well known to consist of 2-acetamido-2-deoxy-β-D- glucose through α, β(1→4) linkage. Chitin is the major source of surface pollution in coastalareas. Chitosan is the N-deacetylated derivative of chitin and their structures are shown in Fig. 1. Fig. 1 Structures of Chitin and Chitosan Because of the excellent properties such as biocompatibility…     

Electronic structure of BeH2

Nonorthogonal single‐configuration and multiconfiguration ab initio calculations are carried out on the BeH₂ molecule in its equilibrium (D_∞h) geometry, using a highly optimized even‐tempered Slater‐type orbital (STO) basis set. The results are used as a basis for a discussion of the electronic structure of the molecule in modern‐VB terms. A value of R_e = 1.329 Å is obtained. Values are also obtained for the symmetric‐stretch harmonic frequency (2053 cm^?1), electric quadrupole moment (?5.60 Buckingham), and nuclear quadrupole coupling constants (?3.59 MHz for ⁹Be and 0.0915 MHz for ²H). © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006     

Polarized basis sets of Slater-type orbitals: H to Ne atoms

We present three Slater-type atomic orbital (STO) valence basis (VB) sets for the first and second row atoms, referred to as the VB1, VB2, and VB3 bases. The smallest VB1 basis has the following structure: [3, 1] for the H and He atoms, [5, 1] for Li and Be, and [5, 3, 1] for the B to Ne series. For the VB2 and VB3 bases, both the number of shells and the number of functions per shell are successively increased by one with respect to VB1. With the exception of the H and Li atoms, the exponents for the VB1 bases were obtained by minimizing the sum of the Hartree-Fock (HF) and frozen-core singles and doubles configuration interaction (CISD FC) energies of the respective atoms in their ground state. For H and Li, we minimized the sum of the HF and CISD FC energies of the corresponding diatoms (i.e., of H(2) or Li(2)) plus the ground-state energy of the atom. In the case of the VB2 basis sets, the sum that was minimized also included the energies of the positive and negative ions, and for the VB3 bases, the energies of a few lowest lying excited states of the atom. To account for the core correlations, the VBx (x = 1, 2, and 3) basis sets for the Li to Ne series were enlarged by one function per shell. The exponents of these extended (core-valence, CV) basis sets, referred to, respectively, as the CVBx (x = 1, 2, and 3) bases, were optimized by relying on the same criteria as in the case of the VBx (x = 1, 2, and 3) bases, except that the full CISD rather than CISD FC energies were employed. We show that these polarized STO basis sets provide good HF and CI energies for the ground and excited states of the atoms considered, as well as for the corresponding ions.     

High yield thiolation of iodobenzene catalyzed by the phosphinite nickel PCP pincer complex: [NiCl{C6H3-2,6-(OPPh2)2}]

[NiCl{C₆H₃-2,6-(OPPh₂)₂}] efficiently catalyzes the thiolation of iodobenzene with a broad scope of disulfides in the presence of zinc, the coupled products are obtained in excellent and in many cases nearly quantitative yields.     

含羟基芳基或氨基芳基的磷酰胺酯衍生物的合成

采用均相反应的方法合成了6个含羟基芳基或氨基芳基的磷酰胺酯衍生物:[(ClCH_2CH_2)_2NP(O)(OPh)(XArY)](X:O,NH;Y:m或p-OH或NH_2).用元素分析、红外光谱、氢核磁共振谱及质谱证实了它们的组成及结构.