HBF4·DEE-catalyzed formation of sulfinyl imines: Synthesis and mechanistic studies

A mild acid-catalysed method is reported for the formation of sulfinyl imines from tert-butanesulfinamide and aromatic or aliphatic aldehydes using tetrafluoroboric acid diethyletherate (10?mol%) in dichloromethane. Reactions were performed at room temperature and gave the corresponding sulfinyl imines in excellent yield after 2?h. A DFT study was performed and a mechanism for the reaction is postulated.     

Square‐Wave Voltammetry of the Molybdenum‐1,10 Phenanthroline‐Fulvic Acids Complex: Redox Kinetics Measurements

The reduction process of molybdenum in the presence of fulvic acids and phenanthroline was investigated by square-wave voltammetry (SWV). The mixed-ligand complex of molybdenum exhibits a pronounced tendency to adsorb onto the mercury electrode surface. The electrode reaction proceeds as a surface process in which both components of the redox couple are firmly confined to the electrode surface. The kinetics of the electrode reaction is studied utilizing the properties of “split SW peaks” and “quasireversible maximum”. The kinetic parameters obtained with two different square-wave voltammetric methods are in good agreement. In 0.5 mol/L NaCl solution with pH 2.5 the kinetic parameters are: standard rate constant k_s=8±2 s⁻¹, cathodic electron transfer coefficient α=0.41±0.05, and number of exchanged electrons n=2. The SW kinetic measurements are confirmed by cyclic voltammetric method.     

五配位锗化合物研究进展

按两种不同的结构类型（中性分子型和离子型）着重对五配位锗化合物的结构特点、研究进展等方面的内容进行了综述。     

Synthesis,Crystal Structure and Antimicrobial Study of N,N,N''-Tris(3-aminopropyl)ethylenediamine Copper(Ⅱ) Diperchlorate

The title compound [Cu(C11H29N5)](ClO4)2 was synthesized and characterized by elemental analysis,IR and X-ray single-crystal diffraction.The compound crystallizes in the monoclinic system,space group P21/n with a = 9.405(2),b = 14.495(3),c = 14.715(3)(A),β = 90.262(3)°,V =2006.1(7)(A)3,Mr = 493.83,Z= 4,F(000) = 1028,Dc= 1.635 g/cm3,T= 298(2) K,μ = 1.403 mm-1 and λ = 0.71073(A).The structure was refined to R = 0.0508 and wR = 0.1250 for 2293 observed reflections with I ＞ 2σ(I).The Cu(Ⅱ)atom possesses a five-coordinate CuN5 environment which shows a slightly distorted square-pyramidal geometry.Antimicrobial activity study found that the complex is active against Salmonella species,Staphylococcus aureu,Bacillus pumilus and Bacillus coliforms.     

Chemico-diffusion kinetics and TTT cure diagrams of DGEBA-DGEBF/amine resins cured with phenol catalysts

Curing of epoxy-amine resins with bisphenol A (BPA) as an external catalyst was studied from differential scanning calorimetry analyses in isothermal and dynamic modes. Both phenomenological and mechanistic models have been tested. The mechanistic model where epoxy cure is postulated to only occur through hydroxyl-catalyzed reactions, and assuming a different reactivity of both types of hydroxyl groups (from BPA and epoxy chains) provided a reasonable fitting of the whole set of experimental data. In particular, the latter model provides good predictive behavior for changes in the mixture composition (BPA content varying in the range from 3 to 10 wt.%, relative to the weight of hardener), contrary to the model based on the same reactivity of both types of hydroxyl groups.The isothermal time-temperature-transformation (TTT) diagram including the time to vitrification and iso-T_g curves of the complex epoxy system was also established.     

A branch-and-cut algorithm for the stochastic uncapacitated lot-sizing problem

This paper addresses a multi-stage stochastic integer programming formulation of the uncapacitated lot-sizing problem under uncertainty. We show that the classical (ℓ,S) inequalities for the deterministic lot-sizing polytope are also valid for the stochastic lot-sizing polytope. We then extend the (ℓ,S) inequalities to a general class of valid inequalities, called the inequalities, and we establish necessary and sufficient conditions which guarantee that the inequalities are facet-defining. A separation heuristic for inequalities is developed and incorporated into a branch-and-cut algorithm. A computational study verifies the usefulness of the inequalities as cuts. This research has been supported in part by the National Science Foundation under Award number DMII-0121495.     

Some selected chapters from the (butadiene)zirconocene story

(Butadiene)zirconocene was the first mono-nuclear metal complex for which the s-trans-η⁴-conjugated diene coordination mode was established. Meanwhile a variety of additional examples from metals throughout the Periodic Table was found. The (butadiene)zirconocenes have found use as valuable reagents in organic and organometallic synthesis, for which various representative examples are described. They have also found extensive use as precursors for the generation of very active and sometimes very selective homogeneous metallocene Ziegler-Natta olefin polymerization catalysts. The employment of the dipolar zirconocene(butadiene)/B(C₆F₅)₃ addition products in mechanistic studies has revealed important aspects of the reaction course taken in the carbon-carbon coupling reaction sequences at this important class of catalysts. Several specific examples are described in this article.     

Square‐Wave Voltammetry of Quasi‐Reversible CE Reactions at Spherical Microelectrodes

A mathematical model for the CE mechanism in which the chemical together with the electrochemical reactions are quasi‐reversible at the surface of spherical macro and micro‐electrodes is presented for the case of square‐wave voltammetry. The analysis of voltammometric responses considers the influence of rate and equilibrium constants, together with the electrode radius, and their dependence on the square‐wave frequency (f). Both kinetics and the sphericity effect act synergistically on the electrochemical response. Also, the apparent electrode sphericity and the reversibility of the chemical as well as the electrochemical reactions are jointly affected by the variation of f. Disregarding the sphericity contribution in the calculation of kinetic parameters at a microelectrode may introduce errors even higher than one order of magnitude. The model allows the analysis of a more realistic and complex electrochemical system that requires not only the dependence of experimental responses on f, but also their fit with theoretical voltammograms, in order to provide some useful mechanistic information. Finally, concentration profiles are also studied to realize how the chemical contribution is buffering the absences of oxidized species at the electrode surface, and how those profiles are modified for the case of spherical macro and micro‐electrodes.     

Theoretical Study on the Structural and Electronic Properties of the Reduced SnO2 （110） Surface

The reduced SnO2(110) surface has been investigated by using first-principles method with a slab model. By examining the vacancy formation energy of three kinds of reduced SnO2(110) surfaces, the most energetically favorable defect surface is confirmed to be the surface with the coexistence of bridging and in-plane oxygen vacancies, which is different with the traditional model by only removing bridging oxygen. The results of band structure calculations indicate that the electronic structure of this defect surface is similar to the SnO surface.     

In Appreciation

Leslie Foldy’s diminutive stature and modest demeanor gave little clue to the powerful intellect responsible for several significant advances in theoretical physics.Two were particularly important. His 1945 theory of the multiple scattering of waves laid out the fundamentals that most modern theories have followed (and sometimes rediscovered), while his work with Siegfried Wouthuysen on the nonrelativistic limit of the Dirac equation opened the way to a wealth of valuable insights. In this article we recall some of the milestones along Foldy’s path through a life in physics. Some of the anecdotes we report here were related to one of the authors (PLT) just before an event in 2000 celebrating Foldy’s 80th birthday, while others were told to us over the course of the nearly forty years during which we were colleagues. Still others were uncovered during the course of WJF’s research for his book, Physics at a Research University: Case Western Reserve 1830–1990 (Cleveland: Case Western Reserve University, 2006). Other details were provided by Foldy’s widow, Roma. Philip L. Taylor is the Perkins Professor of Physics and Professor of Macromolecular Science and Engineering at Case Western Reserve University. William J. Fickinger is Professor Emeritus of Physics at Case Western Reserve University.