Enantioselective synthesis of tetranuclear quadruple helicates

Quadruple helical structures are assembled around a tetranuclear cubane structure using four chiral tridentate ligands and two ligands coordinating diagonally across a face. Stereoselectivity in the complex formation is observed.     

Chebyshev pseudospectral solution of second-order elliptic equations with finite element preconditioning

A new Chebyshev pseudospectral algorithm for second-order elliptic equations using finite element preconditioning is proposed and tested on various problems. Bilinear and biquadratic Lagrange elements are considered as well as bicubic Hermite elements. The numerical results show that bilinear elements produce spectral accuracy with the minimum computational work. L-shaped regions are treated by a subdomain approach.     

Permeabilit?t des Eisens bei hohen Temperaturen

Ohne Zusammenfassung     

Study of structural and electronic transport properties of Ce-doped LaMnO3

The structural and electronic transport properties of La_1−x Ce _x MnO₃ (x=0.0–1.0) have been studied. All the samples exhibit orthorhombic crystal symmetry and the unit cell volume decreases with Ce doping. They also make a metal-insulator transition (MIT) and transition temperature increases with increase in Ce concentration up to 50% doping. The system La_0.5Ce_0.5MnO₃ also exhibits MIT instead of charge-ordered state as observed in the hole doped systems of the same composition.     

Shapes and shifts in the oxygen Auger spectra

The oxidation of silicon and platinum single crystal faces, of polycrystalline supported catalysts and of some alloy surfaces has been studied by AES and as far as possible by LEED. A comparison of the oxygen Auger spectra obtained during the oxidation process with those found on oxides has been made; it shows that the modification of the fine structure of the oxygen Auger peaks gives some information about the binding state of oxygen. Two different structures, which compete one with the other, are described. In one case, a spectrum where three lines dominate is obtained; in the other case, a “quasi-atomic” spectrum characterized by five features is observed: multiplet splitting in the two-hole final state is predominant. Besides these differences in the fine structure of the Auger spectra one can notice shifts of several eV for the main feature. They have been correlated with the various observed LEED patterns. Physisorption, chemisorption, solution of oxygen in the metal lattice, growth of ordered or amorphous oxides are the different possibilities which are discussed.     

Differentiability of convex functions and the convex point of continuity property in Banach spaces

We show that ifX is a separable Banach space, then every continuous, convex, Gateaux differentiable function onX is Fréchet differentiable on a dense set if and only ifX* has theweak*-Convex Point of Continuity Property (C*PCP). Research completed while a visitor at the University of Alberta. Research supported in part by an H. R. MacMillan Fellowship from the University of British Columbia. Research partially supported by NSERC (Canada).     

Nucleophilic partners in the tandem conjugate addition-Dieckmann condensation reaction: 1. synthesis of 1,2,3-trisubstituted naphthalenes

The scope and limitations of the tandem conjugate addition-Dieckmann condensation for the construction of 1,2,3-trisubstituted naphthalenes is defined. Viable nucleophilic partners in this methodology include organocuprates, active methylenes, and a variety of heteroatom initiators.