The cleavage of some bis(perhaloaryl)methylsilanes and tris(perhaloaryl)silanes by organolithium compounds

Bis(perhaloaryl)methylsilanes and tris(perhaloaryl)silanes (halo = Cl, F) undergo reaction with methyl- and butyllithium under mild conditions to produce perhaloaryllithium derivatives in generally high yields.     

Modification of Polyvinyltrimethylsilane in Direct-Current Discharge

High Energy Chemistry - The modification of polyvinyltrimethylsilane under treatment by direct-current discharge at a reduced pressure has been investigated. Polymer films were placed at the anode...     

Measurements of the proton elastic-form-factor ratio mu pG p E/G p M at low momentum transfer

High-precision measurements of the proton elastic form-factor ratio, mu pG p E/G p M, have been made at four-momentum transfer, Q2, values between 0.2 and 0.5 GeV2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q2 range the deviation from unity is primarily due to G p E being smaller than expected.     

3He spin-dependent cross sections and sum rules

We present a measurement of the spin-dependent cross sections for the 3He over -->(e over -->,e')X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1< or =Q2< or =0.9 GeV2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.     

2-Benzazepines. 7. Synthesis of pyrimido[5,4-d][2]benzazepines

Two novel syntheses of pyrimido[5,4-d][2]benzazepines are described. The first synthesis started with 3-phenylphthalide which in three steps was converted to a functionalized pyrimidine which was cyclized to give the 2-benzazepine ring system. The second approach used o-benzoylbenzoic acid methyl ester as the starting material, which in four steps was converted to a functionalized pyrimidine which was cyclized to give a 2-benzazepine. Pyrimido[5,4-d][2]benzazepines have been found to have activity in standard central nervous system (CNS) pharmacological tests.     

A matrix representation for automorphisms of compact Riemann surfaces

In this paper we prove a result which has as corollaries theorems of Hurwitz, Accola, Grothendieck, and Serre on automorphisms of Riemann surfaces.     

Mechanism of shear-induced metallization

It is well-known that volumetric compression converts insulators into metals (the Herzfeld-Mott transition). Not so well-known is the fact that finite shear strains have a similar effect. For example, uniaxial compression of Si and Ge causes them to become metallic. A simple band-structure model for this is presented in this paper. Shear induced metallization has several important consequences, including: mechanically induced phase transformations, other mechanochemistry; the hardnesses of semiconductors and carbides; and ultra-fast reactions at detonation fronts.Dedicated to Dr. Frantiek Kroupa in honour of his 70th birthday.     

The structure of two-parabolic space: parabolic dust and iteration

A non-elementary Möbius group generated by two-parabolics is determined up to conjugation by one complex parameter and the parameter space, the parameter space for representations of groups generated by two parabolics into \({PSL(2, \mathbb{C})}\) modulo conjugacy, has been extensively studied. In this paper, we use the results of Gilman and Waterman to obtain an additional structure for the parameter space, which we term the two-parabolic space. This structure allows us to identify groups that contain additional conjugacy classes of primitive parabolics, which we call parabolic dust groups, non-free groups off the real axis, and groups that are both parabolic dust and non-free; some of these contain \({\mathbb{Z} \times \mathbb{Z}}\) subgroups. The structure theorem also attaches additional geometric structure to discrete and non-discrete groups lying in given regions of the parameter space and allows a new explicit geometric construction of some non-classical T-Schottky groups.