异戊二烯稀土催化聚合过程中配合物结构及其转化的~(13)C-NMR研究

本文用~(13)C-NMR研究了异戊二烯(IP)在均相催化剂(CF_3CO_2)_2LnCl·EtOH—(i-Bu)AlH—o-C_6D_4Cl_2作用下的聚合过程。单体首先被活化同稀土配位生成η~4-IP稀土配合物(反式和顺式),然后η~4-IP的C-3和C-4插入Ln-H键生成η~3-烯丙基稀土配合物——η~3-(2-甲基)丁烯基稀土配合物(同式和对式)。二维~(13)C-NMR交换谱表明η~4-IP和0η~3-烯丙基的每对异构体在常温下分别进行慢交换反应(互变异构),这一过程使插入反应在常温下得以进行。     

The First Rotational Isomers of Stable Selenobenzaldehydes and their η1-Tungsten Complexes

The first rotational isomers of stable selenoaldehydes are synthesized by deselenation of cyclic polyselenides having an efficient steric protection group, 2, 4, 6-tris[bis(trimetylsilyl)methyl]phenyl (Tbt). Reactions of these selenoaldehydes with W(CO)₅.THF gives the corresponding η¹-selenoaldehyde tungsten complexes, the structures of which are established by X-ray crystallography.     

Organodiphosphines in cis-Pt(η2-P2L)(η2-S2L) derivatives – structural aspects

Abstract

In this review structural parameters of forty complexes with an inner coordination sphere of Pt(η²-P₂L)(η²-S₂L) are analyzed and classified These complexes crystallize in three crystal systems: orthorhombic (four examples), triclinic (six examples) and monoclinic (thirty examples). The organodiphosphines create four- (PCP), five- (PC₂P), six- (PC₃P) and seven- (PC₄P) membered metallocyclic rings with mean P-Pt-P bite angle values of 72.5° (PCP) < 85.3° (PC₂P) < 93.0° (PC₃P) < 97.4° (PC₄P). The dithiolates create four- (SCS), five- (SC₂S), six- (SC₃S; SCSCS; SPNPS; SPCPS) and seven- (SC₄S) membered metallocyclic rings with mean S-Pt-S bite angle values of 74.5° (SCS) < 85.8° (SCSCS) < 87.0° (SPNPS) < 89.0° (SC₂S) < 92.3° (SC₄S) < 93.5° (SC₃S) < 97.5° (SPCPS). The mean Pt-P and Pt-S bond distances are 2.257 and 2.328?Å, respectively. The data are compared with those found in complexes with inner coordination spheres of Pt(PL)₂(SL)₂, Pt(PL)₂(η²-S₂L) and Pt(η²-P₂L)(SL)₂.     

η-INVARIANT AND CHERN-SIMONS CURRENT

The author presents an alternate proof of the Bismut-Zhang localization formula of ηinvariants, when the target manifold is a sphere, by using ideas of mod k index theory instead of the difficult analytic localization techniques of Bismut-Lebeau. As a consequence, it is shown that the R/Z part of the aualytically defined η invariant of Atiyah-Patodi-Singer for a Dirac operator on an odd dimensional closed spin manifold can be expressed purely geometrically through a stable Chern-Simons current on a higher dimensional sphere. As a preliminary application, the author discusses the relation with the Atiyah-Patodi-Singer R/Z index theorem for unitary flat vector bundles,and proves an R refinement in the case where the Dirac operator is replaced by the Signature operator.     

Poisson流形上微缩算子η的应用

本文根据Poisson流形P的1-形式空间∧1(P)上的微缩算子η及其性质,给出了η-代数胚的定义,进一步得到了微缩算子在η-代数胚及Poisson流形中的一些应用.     

A class of B-(p,r)-invex functions and mathematical programming

Invexity of a function is generalized. The new class of nonconvex functions, called B-(p,r)-invex functions with respect to η and b, being introduced, includes many well-known classes of generalized invex functions as its subclasses. Some properties of the introduced class of B-(p,r)-invex functions with respect to η and b are studied. Further, mathematical programming problems involving B-(p,r)-invex functions with respect to η and b are considered. The equivalence between saddle points and optima, and different type duality theorems are established for this type of optimization problems.     

ε－次可微多目标规划的最优性条件

本文主要从多目标规划相应的加权问题出发，讨论了在ε－次可微的条件下，凸多目标规划问题η－有效解存在的必要条件与充分条件．     

Structural changes in β-lactoglobulin by conjugation with three different kinds of carboxymethyl cyclodextrins

β-Lactoglobulin-carboxymethyl cyclodextrin (β-LG-CMCyD) conjugates were prepared by using water soluble carbodiimide. Three kinds of CMCyDs differing in molecular mass were used to investigate the effects of different CMCyD contents, net charge and hydrophobicity on the structural changes in β-lactoglobulin. The effect of CMCyDs on the structure of β-lactoglobulin was utilized to investigate the contribution of hydrophobic interactions to the stability of the protein. Spectroscopic studies suggested that the conformation around had not changed in either conjugate but the α-helix content of β-LG-CMCyD conjugates had markedly increased as compared with that of β-lactoglobulin. The differential scanning calorimetry technique confirmed that the addition of one glucose unit in β-LG-CMCyD conjugates, enthalpy change of calorimetry decreased and the denaturation temperature of each conjugate was higher than that of native β-lactoglobulin. The heat contents agreed well with the conformational transition measured by molar ellipticity at 222 nm ([θ]₂₂₂) and Stoke's radius (R_S) values. Therefore, hydrophobic forces play an important role in stabilizing and shielding of the β-LG-CMCyD conjugates.     

Symmetric duality with (p, r) − ρ − (η, θ)-invexity

In this paper we introduce a new type of generalized invex function, called (p, r) − ρ − (η, θ)-invex function and study symmetric duality results under these assumptions. In our study the nonnegative orthants for the constraints are replaced by closed convex cones and their polars. We establish weak and strong duality theorems under (p, r) − ρ − (η, θ)-invexity assumptions for the symmetric dual problems. We also give many examples to justify our results.     

强(A,η)-增生算子及其在变分包含中的应用

本文引入一类广义增生算子——强(A,η)-增生算子.定义强(A,η)-增生算子的广义预解算子并证明它的Lipschitz连续性,进一步证明含强(A,η)-增生算子的变分包含的一些新的迭代算法的收敛性.所得结果改进和推广了许多文献的相应结果.