Electrochemical synthesis of π-indenyl-π-(3)-1,2-dicarbollyliron(III)

Co-electrolysis of potassium 1,2-dicarbadodecahydroundecaborate and indene in 0.1N sodium bromide solution in dimethylsulfoxide using iron electrodes afforded ntent/n251323828716v45/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-indenyl-ntent/n251323828716v45/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-(3)-1,2-dicarbollyliron(III).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 764–765, April, 1993.     

Reactions of regioisomeric fluoroalkyl-containing β-aminovinyl ketones with hydrazines

Fluoroalkyl ntent/n757146t92365416/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-alkyl-ntent/n757146t92365416/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-aminovinyl ketones react with hydrazine hydrate to give the respective razoles and with phenylhydrazine they form a mixture of pyrazoles and 5 hydroxy-ntent/n757146t92365416/xxlarge948.gif" alt="delta" align="BASELINE" BORDER="0">²-pyrazolines. Alkyl(aryl) ntent/n757146t92365416/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-fluoroalkyl-ntent/n757146t92365416/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-aminovinylketones do not react with the hydrazines mentioned above. With 2,4-dinitrophenylhydrazine, both types of fluoroalkyl-containing ntent/n757146t92365416/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-aminovinyl ketones give only hydrazones of the corresponding methyl alkyl(aryl) ketones.     

Effect of Oxygen Redistribution on the Normal and Superconducting Properties of Yttrium High‐Temperature Superconductors

An anomaly is found in the vicinity of T_maxntent/p017n3j24422t914/xxlarge8764.gif" alt="sim" align="MIDDLE" BORDER="0"> 560$ K on electric resistance versus temperature curves for yttrium highntent/p017n3j24422t914/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">temperature superconductors of the 123 phase. Xntent/p017n3j24422t914/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">ray phase analysis suggests a structural phase transition in the vicinity of T_max due to oxygen redistribution in the mobile sublattice of this compound. Investigation of samples with Y partially replaced by Ca has shown that the structural phase transition does not depend on carrier concentration in the conduction band.     

An efficient ab initio gradient program

An ab initio Hartree-Fock gradient program is described. It is characterized by (1) efficiency of the gradient evaluation, and (2) capability of handling higher angular momentum (d andf) basis functions. The latter are constructed from shifted Cartesian Gaussian p-type primitives. A satisfactory solution is presented for the problems connected with the neglect of small integrals in a gradient program. Methods for increasing the efficiency of the SCF procedure are discussed.     

Interactions of proteins with uniform colloidal hematite and chromium hydroxide particles. I. Adsorption

The adsorption of ovalbumin, ntent/vg346089n13m2880/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-globulin, and lysozyme on uniform spherical hematite and chromium hydroxide particles in aqueous media has been studied as a function of the pH at a constant ionic strength. The uptake of ovalbumin and ntent/vg346089n13m2880/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-globulin was greatest at their isoelectric points and differed little at 10^–2 and 10^–3 mol dm^–3 NaNO₃. The adsorption of lysozyme was strongly influenced by the ionic strength.The deposition of ovalbumin on hematite in the presence of Mg (NO₃)₂ was significantly greater than that with NaNO₃ under otherwise comparable conditions. Dialysis experiments with ovalbumin against magnesium nitrate solutions showed Mg²⁺ to be specifically bound to the protein.The shapes of isotherms indicated monolayer coverage for ovalbumin and multilayer coating for lysozyme for both adsorbents. The shapes of isotherms of ntent/vg346089n13m2880/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-globulin on hematite point to a rearrangement of the protein on the particle surface, while a monolayer was found on chromium hydroxide particles.Supported by the NSF Grant CHE-9108420Part of a Ph.D. thesis     

Effect of hydrophobic amino acids on the conformational change of decapeptides in micellar environments

A series of peptides containing various hydrophobic amino acids [methionine (Met), leucine (Leu), norleucine (Nle), phenylalanine (Phe), 2-aminooctanoic acid (Aoc), and 2-aminodecanoic acid (Ade)] were synthesized and their conformations were studied using circular dichroism (CD) spectroscopy in different solvents such as water, methanol, and aqueous solution of ammonium tetradecanesulfonate. Peptides containing hydrophobic amino acids with linear side chains formed ntent/rktjqutxh31x0n8e/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-sheets in water and methanol. Electrostatic interaction between the charged side chain (lysine) and a micelle consisting of an anionic surfactant, ammonium tetradecanesulfonate, is necessary for the formation of ntent/rktjqutxh31x0n8e/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-helices in micellar environments. The conformational transition from ntent/rktjqutxh31x0n8e/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-helix to ntent/rktjqutxh31x0n8e/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-sheet structure required moderate hydrophobicity and linear side chains. This conformational transition depended on the surfactant concentration.     

Structure-Activity Relationship of Insecticidal Steroids. V. 3β-Benzoyloxystigmastan-6-ones

The toxicity of steroid benzoates 4-10 for Colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by a contact-intestinal method. The most active growth and development regulator for this insect is 3ntent/r2t171242406n553/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-benzoyloxy-5-hydroxy-ntent/r2t171242406n553/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">⁷-6-ketosteroid 9a.     

Novel Fabrication of Conductive Polymers Contained Micro‐Array Gas Sensitive Films Using A Micromanipulation Method

A novel method for fabricating a micro gas sensor film on an indium tin oxide (ITO) electrode patterned using micro‐machining technology was developed. A micromanipulation system equipped with a counter electrode (Au; Ø10 μm) and a microsyringe, which was connected to a microinjection system, was first constructed. With this system, micro gas sensor arrays could be successfully prepared on ITO electrodes. Two kinds of micro gas sensor films were prepared, based on polythiophene (PTh) and poly(3‐n‐dodecylthiophene) (PD). The response behavior of conventional PTh and micro‐PTh films against NH₃ at three different operating temperatures (25, 40 and 60 °C) was investigated by measuring the resistance of the film. With the micro‐PTh film, a reversible response was observed against NH₃ when measured at 40 and 60 °C. In addition, the responsive characteristics of the microsensor films against different testing gases were examined at the three operating temperatures. The resistance of the microsensor films of PTh and PD changed considerably, depending on the type of testing gas, allowing these sensor films to be used for the detection of various gases. Furthermore, the microsensor films had a high stability compared with conventional films prepared from the same polymer.     

Tetramethyldisilan-1,2-diyl-verbrückte Dicyclopentadienyl-und Diindenylmetalldichloride der 4. Gruppe – Kristallstruktur von

Tetramethyldisilane-1,2-diyl bridged Dicyclopentadienyl and Diindenyl Metal Dichlorides of the Group 4 Metals – Crystal Structure of ng="lazy" alt="equation image" class="section_image" src="/cms/asset/000d98ef-6e39-4521-8098-54751dfe05bb/nueq001.gif"> Dicyclopentadienyl and diindenyl metal dichlorides of the type Cp′? SiMe₂SiMe₂? Cp′MCl₂ (Cp′ = C₅H₄, M = Ti ( 1 ), Zr ( 2 ), Hf ( 3 ); Cp′ = C₉H₇, M = Zr ( 4 ), Hf ( 5 )) were synthesized and characterized by means of their ¹H, ¹³C, ²⁹Si-n.m.r., MS, and IR spectra. The crystal structure of 2 was determined.     

Transferability of some properties of localized molecular orbitals

The transferability of the first and second order electric moments of localized orbitals have been shown. Some moment characteristics have also been investigated. The standard deviation of first order localized moments is less than 2.0%. The standard deviation of second order electric moment components are larger: although they do not exceed 4.0% for bond orbitals, for lone pair ones they vary about 1.5–10.1%.