The probability of electron scattering from atomic core states as a function of electron energy, can be extracted from secondary electron yields by differentiation. Fine structure variations above the thresholds for excitation of the vanadium 2p and 2s states are found to extend for several hundred electron volts. The fine structure is altered significantly by reaction of the surface with CO, but is insensitive to long-range order. The structure exhibits periodicities in k, and persumably...
Topics: DTIC Archive, Cohen,P I, MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS AND ASTRONOMY, *ELECTRONIC...
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xii, 123 pages : 23 cm
Topics: Pharmacologie quantique, Biochimie quantique, Quantum biochemistry, QSAR (Biochemistry), Drugs --...
This paper reports results of the characterizations of nanoparticle assembly formed via spontaneous core-shell and shell-shell reactivities at thiolate-capped gold nanoparticles. Gold nanoparticles of two different core sizes and thiols with carboxylic acid terminals are exploited as a model system. The reactivities involve covalent Au-thiolate bonding and non-covalent hydrogen-bonding with anisotropic linking character. We employed infrared reflection spectroscopy (IRS), atomic force...
Topics: DTIC Archive, Han, Li, Maye, Mathew M., Zhong, Chuan-Jian, STATE UNIV OF NEW YORK AT BINGHAMTON...
An investigation of the explosive oxidation of tetraborane and the partial oxidation of tetraborane was undertaken. Mixtures of tetraborane with O, and with O and inert gas were prepared at known pressures and temperatures in the reaction bulbs; these mixtures exploded on heating. The data obtained indicated a branching chain reaction with chain initiation in the gas phase AND CHAIN BREAKING ON THE WALL OF THE VESSEL. The entire range of pressures and temperatures investigated shows the...
Topics: DTIC Archive, LUDLUM, KENNETH H, RENSSELAER POLYTECHNIC INST TROY NY, *BORON COMPOUNDS,...
Over the past fifteen years, the use of ESCA and infrared techniques have made great strides in relating the differences between polymer surface composition and structure and the bulk composition and structure. Much has been learned about the role of synthetic structural design and the role of processing variations and the resulting surface structure and composition of polymers. Yet, a quantitative description of segment length distribution at the surface of a multicomponent polymer remains...
Topics: DTIC Archive, Zhuang, H. -Z., STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY, *DISTRIBUTION,...
A benzobistriazolo phenanthroline polymer was prepared by the polycondensation of 2,6-pyridinediyldihydrazidine with 1,4,5,8-naphthalene tetracarboxylic acid or 1,4,5,8-naphthalene tetracarboxylic dianhydride in polyphosphoric acid. Inherent viscosities in the range of 0.25-0.87 dl./g. were recorded. Polymer structure was established by elemental and infrared analysis. The polymer was a reddish-brown powder soluble in sulfuric-or methane sulfonic- acid. Onset of breakdown during...
Topics: DTIC Archive, Evers, Robert C, AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OH, *HEAT RESISTANT...
Computer analysis of protein models is used to aid design of new protein structures. Using atomic coordinates of beta-bellin, an antiparallel beta-sheeted protein model designed by Jane & David Richardson, characteristics such as solvent-accessible surface, polypeptide backbone twist, beta-barrel geometry, empirical potential energy etc. were computed and compared with values obtained from atomic coordinates of native proteins. This approach involves computer analysis of native proteins as...
Topics: DTIC Archive, Novotny,Jiri, MASSACHUSETTS GENERAL HOSPITAL BOSTON, *PROTEINS, *MOLECULAR STRUCTURE,...
A principal focus of this research program is the electronic structure aspects of nonadiabatic processes related to the stability and formation of high energy density materials(HEDMs). Also considered are nonadiabatic and relativistic effects that impact the detection of molecular species involved in HEDM or chemical laser development. These studies are enabled by a unique system of electronic structure algorithms, the BROOKLYN programs, that provide advanced capabilities for the study of the...
Topics: DTIC Archive, Yarkony, David R., JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF CHEMISTRY, *ALGORITHMS,...
Using Beta/Beta prime dimethypyrrole polymers to reduce the structural disorder it has been possible to interpret the results of electron diffraction data and to propose and idealized structure for neutral polypyrrole. XPS data have been used to define some of the deviations from this ideal structure that are seen in actual films and the origin of some of these defects is related to the mechanism of polymerization. The planarity of the chain structure is shown to be important for high...
Topics: DTIC Archive, Street,G B, IBM RESEARCH LAB SAN JOSE CA, *CONDUCTIVITY, *POLYMERS, *X RAY...
There has been considerable interest in recent years in the development of novel polymeric materials through blending rather than through development of new chemical structures. Blending may be chosen for several reasons, for example, tailoring properties to meet a specific need or simplifying recycling efforts by reducing separation procedures. Development of useful blends is challenged by the inherent immiscibility of most polymers with one another, which results in coarsely phase separated...
Topics: DTIC Archive, Tan, Nora C., AIR FORCE RESEARCH LAB BOLLING AFB DC, *POLYMERS, *REACTIVITIES,...
The goal of this research was to carry out a theoretical study of the generation and control of quantum-degenerate molecular systems, including but not limited to dipolar molecules. Major directions includde (a) the controlled association of diatomic as well as more complex ultracold heteronuclear molecules, such as molecular trimers, into deeply bound states; (b) the study of the coherent dynamics and quantum control of elementary chemical reactions such as for instance the displacement...
Topics: DTIC Archive, ARIZONA UNIV TUCSON, *MOLECULES, CANTILEVER BEAMS, CHEMICAL REACTIONS, DIPOLES,...
For this study, thin film Se samples were vacuum deposited in order to produce a molecular structure significantly different from those of the previously studied melt-quenched samples. The structure differences should have been reflected in changes in their macroscopic properties. Consideration was given to the shear and volume viscosity, and heat capacity of configurationally equilibrated systems. No observable differences from melt-quenched samples were found. This was an indication that the...
Topics: DTIC Archive, Stephens,R B, HARVARD UNIV CAMBRIDGE MASS DIV OF ENGINEERING AND APPLIED PHYSICS,...
Calculations are presented of vibrational absorption spectra for energy minimized structures of PCE-nH2O, TCE-nH2O, DCE-nH2O, andVC-nH2O molecular clusters using density function theory (DFT). DFT can provide interpretation of absorption spectra with respect to molecular structure for excitation by electromagnetic waves at frequencies within the IR range. The absorption spectrum corresponding to excitation states of these molecular clusters, which consist of relatively small numbers of atoms,...
Topics: DTIC Archive, Huang,L, NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States, density...
The mechanism of degradation of poly(bis(trifluoroethoxy)(phosphazene) (PBFP) and poly(bis(phenoxy)(phosphazene) (PBPP) have been examined using dynamic and isothermal thermogravimetry. The dynamic experiments were made between 50 deg and 750 deg C at several heating rates from 2.5 deg to 80 deg C/min. and the isothermal measurements were made at 325 deg, 340 deg, 355 deg and 370 deg C. The polymers and their degraded residues were characterized by gel permeation chromatography, infrared...
Topics: DTIC Archive, Peddada,S V, PITTSBURGH UNIV PA DEPT OF METALLURGICAL AND MATERIALS ENGINEERING,...
A novel set of diblock copolymers has been examined in various molecular and morphological characterization experiments, in small amplitude dynamic mechanical tests and in large deformation experiments. In all of the materials studied, one of the block sequences is atactic polystryrene; the second block is comprised of either 1,2 polybutadiene (essentially 100% vinyl adduct and atactic microstructure) or its hydrogenated product, polybutene-1 (also atactic). There is a pronounced influence of...
Topics: DTIC Archive, Cohen,R E, MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMICAL ENGINEERING, *BLOCK...
Polysilanes have use in applications where photosensitivity is required and as precursors to beta-SiC. Polysilanes are usually prepared from dichloroorganosilanes and sodium at approx. 100 C. Several reports of transition metal catalyzed formation of polysilanes from R2SiH2 and RSiH3 have appeared in which product distributions have been the main focus. Herein we report the synthesis and structural characterization of a series of platinum-silyl dimers with unusually short cross-ring Si-Si...
Topics: DTIC Archive, Zarate, Eugene A, CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF CHEMISTRY, *SILICON...
The major focus of work in this laboratory concerns the relationship between molecular structure and biological function. The research includes molecular biological studies in which alternative conformations of the nucleic acids may play an important role. In addition, there are a variety of x-ray diffraction studies of nucleic acids and related compounds in order to uncover the role that molecular conformation plays in interactions. In previous years, attention was directed towards...
Topics: DTIC Archive, Rich, Alexander, MASSACHUSETTS INST OF TECH CAMBRIDGE, *GENETICS, *FUNCTIONS,...
A process for the manufacture of metal nitride sintered bodies, in particular, a process in which a mixture of metal nitrite powders is shaped and heated together with a binding agent is described. Of the metal nitrides Si3N4 and AIN were used especially frequently because of their excellent properties at high temperatures. The goal is to produce a process for metal nitride sintered bodies with high strength, high corrosion resistance, thermal shock resistance, thermal shock resistance, and...
Topics: NASA Technical Reports Server (NTRS), BINDERS (MATERIALS), CORROSION RESISTANCE, HIGH STRENGTH,...
The reaction of 1,1'-bicobaltocene(Co(III)Co(III)-(PF6)2, (BFDCo(III,III)(PF6)2, or the analogous mixed valence compound (Co(III)Co(II)) with excess ((C2H5)3NH)(TCNQ)2 and TCNQ yields the complex salt 1,1'-bicobaltocene(Co(III)Co(III)((TCNQ)3. Reaction of (BFDCo(III,III))(PF6)2 with excess tetrabromoquinone (bromanil, BA) and its sodium salt produces (BFD-Co(III,III))(BA)3, while reaction with tetrabromodiphenoquinone (TBDQ) yields (BFDCo(III,III))(TBDQ)3. The TCNQ units in the complex salt...
Topics: DTIC Archive, Lau,Chak-Po, NORTH CAROLINA UNIV AT CHAPEL HILL DEPT OF CHEMISTRY, *COMPLEX...
In this collaborative effort on shock initiation in solids, advances were made in fundamental concepts and methods of investigation. A new theory was developed for shock-induced vibrational excitation, based on translation to vibration energy conversion. The key novelty of this work is the treatment of multiple correlated impulsive forces acting coherently on the internal degrees of the molecule as the shock wave passes. This theory is in excellent agreement with explicit simulations. The...
Topics: DTIC Archive, Apkarian, Ara V, CALIFORNIA UNIV IRVINE DEPT OF CHEMISTRY, *SHOCK WAVES, *EXPLOSIONS,...
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Dec 23, 2019
12/19
by
Thompson, Paul Everett, 1911-
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xii, 395 pages 24 cm
Topics: Antimalarials -- pharmacology, Antimalarials, Antipaludiques, Antimalariamittel, Antimalarial drugs...
The factors governing chemical reactivity with special reference to the role of electronic energy in promoting the reaction and to the production of electronically excited species are examined. The problem is studied both in general terms (i.e., the development of the required theoretical framework) and in application to specific systems. (Author)
Topics: DTIC Archive, Levine,R D, HEBREW UNIV JERUSALEM (ISRAEL) DEPT OF PHYSICAL CHEMISTRY, *ELECTRON...
Studies on electrons, atoms and molecules, and their concerted action in gases, liquids and solids, has made the building of materials and devices to order, i.e., molecular engineering, possible. The theory of matter is discussed under the following subjects: Web of electron clouds; Atom structure, Elements and compounds; Molecules and crystals; Laws of molecular architecture; Structure and properties.
Topics: DTIC Archive, VON HIPPEL, A, MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR INSULATION RESEARCH,...
Preferred orientation of a molecular unit in vitreous B2O3 films prepared under tensile stress is demonstrated by laser Raman spectroscopy. The polarized Raman scattering is reported and found to be strongly dependent on sample orientation and polarization of the incident and scattered light. The ratios of scattering intensities in the various scattering arrangements for films are substantially different from those for bulk B2O3(gl). Calculated Raman intensity ratios based upon the proposed...
Topics: DTIC Archive, Windisch,Charles F, BROWN UNIV PROVIDENCE RI DEPT OF CHEMISTRY, *RAMAN SPECTROSCOPY,...
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Sep 30, 2020
09/20
by
Wheatley, P. J
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vi, 264 p. : 21 cm
Topic: Molecular structure
Abstract--t-Bu2GaAs(SiMe3)22 (I) and t-Bu2GaAs(SiMe3)2Ga(t-Bu)2Cl were not produced from reaction mixtures of t-Bu2GaCl with (Me3Si)3As (1:1 and 2:1 mole ratio mixtures) and only starting materials were recovered. However, t- Bu2GaC1 reacts with LiAs(SiMe3)2 2THF. Compound II is the fifth example of a compound containing the Ga-As-Ga-X (X = Cl, Br) core, and the second wherein the organogallium four-membered ring with arsenic, halogen mixed bridging is not puckered. In addition to partial...
Topics: DTIC Archive, Wells, Richard L, DUKE UNIV DURHAM NC DEPT OF CHEMISTRY, *RATIOS, SYNTHESIS, X RAY...
There has been remarkable growth throughout the 1980s in the chemistry of transition metal oxo complexes. Interest in what had been regarded as a mature area was rekindled in part by the recognition of the role of the oxo functionality as a 'spectator' ligand in catalytic alkene metathesis, and has been fueled by developments in the chemistry of transition metal porphyrin oxo complexes (including their roles in hydrocarbon oxidations and in alkene epoxidation and hydroxylation reactions), by...
Topics: DTIC Archive, Jernakoff, Peter, PITTSBURGH UNIV PA DEPT OF CHEMISTRY, *COMPLEX COMPOUNDS,...
We have achieved two objectives: (1) we developed the theory of electron scattering by adsorbed molecule and used it to demonstrate that electron scattering is a good probe of the orientation of a chemisorbed molecule. (2) We developed the theory of photodissociation with ultrashort pulses, analyzed existing experiments and showed that coherence and interference play a central role in the dissociation process. By using numerical simulations we proposed and documented new types of experiments...
Topics: DTIC Archive, Metiu, H, CALIFORNIA UNIV SANTA BARBARA DEPT OF CHEMISTRY, *METALS,...
With the development of software implementing quantum chemical techniques that employ energy gradient and Hessian data, and the concurrent increase of access to modern supercomputers, systematic studies of molecular structures and properties have become routine. Recently, several groups have reported efforts to compute accurate values of molecular heats of formation. People and coworkers described a study of first-row hydrides using full fourth- order perturbation theory with a variety of basis...
Topics: DTIC Archive, Adams, George F, ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD, *DIATOMIC...
The ground (S0) and excited (S1) state geometries of alpha- methylstyrene (2-phenylpropene,2) are investigated by mass resolved excitation spectroscopy. In contrast to styrene, which has an intense spectral S1-S0 origin transition, alpha-methylstyrene exhibits a weak origin transition and a long progression in a low frequency torsional mode, with an energy level spacing of approx. 69/cm. The intensity maximum of this progression occurs at the eighth peak position, indicating that the minimum...
Topics: DTIC Archive, Grassian, V H, COLORADO STATE UNIV FORT COLLINS DEPT OF CHEMISTRY, *MOLECULAR...
The purpose of this paper is to explore the use of several model potential energy functions in order to try better to understand the nature of the ofrces which operate between simple monatomic cations and the molecules of solvent which surround them. This work builds upon and extends a recently reported initial treatment. In that report, the potential energy was modelled as the sum of an exponential (Born-type) repulsion and an ionic-dipolar attraction. In this paper we consider composite...
Topics: DTIC Archive, Schmidt,P P, OAKLAND UNIV ROCHESTER MICH DEPT OF CHEMISTRY, *CATIONS, *MOLECULES,...
There exist examples of systems in which small, simple metallic cations are associated with ring-like molecules (e.g., aromatic radical anions), with aggregates of molecules which encage the ion (e.g., solvation and coordination), or special molecules which trap ions within the molecular structure (crypts). For each of these examples, the harmonic oscillations of the ion in the presence of the molecular structure can be observed. Moreover, in many instances, the stability of the ionic motions...
Topics: DTIC Archive, McKinley,J M, OAKLAND UNIV ROCHESTER MICH, *IONS, *METALS, *ATOMS, *MOLECULAR...
The physics and chemistry of clusters is discussed. First, clusters are compared with molecules, on the one hand, and then with solids on the other. It is found that clusters are an intermediate state, and therefore of special interest. The Huckel model is elucidated since this is the simplest of possible semi-empirical methods, and since it is readily applied to clusters. Two kinds of clusters are discussed in greater detail: alkali-metal clusters, because they are the obvious candidate for...
Topics: DTIC Archive, Jelski, Daniel A, STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY, *ALKALI...
This study was designed to characterize the molecular structure of the active site of human acetylcholinesterase (AChE). Human erythrocyte acetylcholinesterase was purified to 98% Homogeneity by monoclonal antibody affinity chromatography and homogeneity by monoclonal antibody affinity chromatography and size-exclusion HPLC, and amino acid sequence data for 100 residues were obtained from tryptic, chymotryptic, and V-8 peptide fragments of the enzyme. These sequence data were used to synthesize...
Topics: DTIC Archive, August, Thomas J, JOHNS HOPKINS UNIV BALTIMORE MD, *BIOSYNTHESIS, *CLONES,...
The calculated spectrum of longitudinal compressional waves on DNA polymer chains is shown to be in excellent agreement with recently performed inelastic neutron scattering measurements in hydrated, oriented DNA crystals. This opens up a previously unexplored frequency regime of DNA science and establishes the validity of the phonon, extended wave description of DNA elementary excitations in this region. Keywords: Deoxyribonucleic acid, Riboxynucleic acid.
Topics: DTIC Archive, Schroll, W K, PURDUE UNIV LAFAYETTE IND DEPT OF PHYSICS, *CRYSTALS, *DEOXYRIBONUCLEIC...
Polymers with side-chain groups capable of crystallization independent of the backbone have been of interest for many years. Recent reviews summarize the syntheses and characterization of a large number of different families of comb polymers. The easiest to synthesize and evaluate with respect to property trends in a homologous series are those containing linear alkyl side-chains. Derivatives with greater than 8-12 carbons form side-chain crystals with hexagonal packing of the alkyl moieties....
Topics: DTIC Archive, Mathias, Lon J, UNIVERSITY OF SOUTHERN MISSISSIPPI HATTIESBURG DEPT OF POLYMER...
In a molecular composite, a ductile matrix is reinforced with a stiff, strong, rigid-rod polymer molecule. One of the approaches used to make a rigid-rod molecular composite involves the physical mixing by coprecipitation of single-phase solutions of a rigid-rod and a flexible-coil polymer in a common solvent. We and others have reported previously on the preparation of three-dimensional fibrous materials using the phase separation of polymer solutions at low temperature and sublimation or...
Topics: DTIC Archive, Alonso, Marie A, CONNECTICUT UNIV STORRS INST OF MATERIALS SCIENCE, *MACROMOLECULES,...
The unidentified infrared (UIR) features are a group of emission bands observed in a variety of objects, which can be characterized as having moderate density gas (densities from 1000 to 1,000,000/cu.cm.) and a nearby ultraviolet source. The origin of the features is still uncertain, but the current evidence points to Polycyclic Aromatic Hydrocarbons (PAHs) as the source of the UIR features. Problems with identifying PAHs as the source of the UIR features are discussed.
Topics: NASA Technical Reports Server (NTRS), EMISSION SPECTRA, HYDROCARBONS, INFRARED SPECTRA, ATOMIC...
This report examines the structure and physical properties of the surface of ice: a liquid-like layer on the ice surface, its thickness and molecular structure, surface conductivity, surface electric charge, surface potential, surface diffusion and so forth. The author reviews experimental results and theoretical models on ice adhesion, gas adsorption and ice sintering. Special attention is given to the results of studies from the last two decades. Among the experimental techniques under...
Topics: DTIC Archive, Petrenko, Victor F, THAYER SCHOOL OF ENGINEERING HANOVER NH, *SURFACES, *ICE,...
The goals for this project are to develop technologies and methodologies for the millimeter/submillimeter (mm/submm) region (100 - 1000 GHz) of the electromagnetic spectrum and to exploit them for the study of molecular systems, particularly in non-ambient and other interesting environments. For the purposes of this discussion we have divided the report on research results into three parts: (1) Energy transfer in polyatomic molecules; (2) Molecular collisional processes at very low temperature...
Topics: DTIC Archive, De Lucia, Frank C., OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS, *MOLECULAR...
Low frequency phonon modes of a helical DNA olygomers- were calculated and compared. The customized program -cages JiMA and UGAND (developed in Dr. Laverys group lBPc. Paris) were was adopted for IBM PC and employed to minimize potential energy and to calculate vibrational frequencies of a molecule. The initial geometry for the B-helix oligonucleotides d(TATATATATATA)d(ATATATATATA) and d(A AAAAAAAAAAA)d(TTTTTTTTTTTT) was created by program JUMNA. The energy of interatomic interactions was...
Topics: DTIC Archive, Bykhovskaia, Maria, VIRGINIA UNIV CHARLOTTESVILLE, *DEOXYRIBONUCLEIC ACIDS,...
In this final report, we describe the results of our ONR-funded research project in theoretical and computational chemistry. We briefly review our ONR-supported work in the following areas: (1) Development of methodology for simulating nonadiabatic dynamics in molecular systems. (2) A proposal for a new type of direct spectroscopy of ultrafast many-body bath dynamics, called nanoscale shock wave spectroscopy, and the results of molecular dynamics simulations describing its theoretical...
Topics: DTIC Archive, Martens, Craig C, CALIFORNIA UNIV IRVINE DEPT OF CHEMISTRY, *MOLECULAR DYNAMICS,...
High-power picosecond UV pulses from a Nd:YAG mode-locked laser were used to induce a visible emission from a variety of gaseous organic molecules. We report the observation of electronically excited C2, CH, CN and H fragments. The spectral characteristics and time development of the emitting species are highly dependent upon the structure of the parent molecules. (Author)
Topics: DTIC Archive, Craig,B B, NAVAL RESEARCH LAB WASHINGTON DC, *PHOTOLYSIS, *GASES, *ORGANIC RADICALS,...
Discharges processing is becoming more and more important in many industries. This paper attempts to bring together, in relatively compact form a basic derivation of the physics of processing discharges including collision theory, kinetic theory, simple chemical reactions, fluid formulations and sheath physics.
Topics: DTIC Archive, Manheimer, Wallace M, NAVAL RESEARCH LAB WASHINGTON DC, *PLASMAS(PHYSICS), *GAS...
This report describes the construction and testing of a new electron energy loss spectrometer to study the band structure of GaAs and other materials using the inelastic scattering of 230keV electrons. Substantial progress has been made towards the realization of a working experiment in high-energy electron energy loss spectroscopy, with which to study the electronic states in GaAs and other materials. In the following sections we give details of our progress in the major components of the...
Topics: DTIC Archive, Weiler,Margaret H, MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF PHYSICS, *GALLIUM...
This report describes a series of computer programs which allows drawings of complex chemical structures to be displayed on a graphic terminal, to be modified using the graphical input devices and finally, to be drawn by an incremental plotter. The system thus provides a means for the interactive development of chemical structure diagrams and for the production of high quality drawings suitable for inclusion in published reports. The system is based on the graphical definition of several...
Topics: DTIC Archive, Sharples,G, ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND), *CHEMISTRY, *COMPUTER...
Work has continued on two projects supported by AFOSR. We continued to improve the projection superposition approximation (PSA) algorithm through a more careful consideration of how to calculate cross sections for elongated molecules, especially if they are bent at sharp angles. The completed algorithm is now available for worldwide use on a dedicated server/website at UCSB. We have also continued to pursue the assembly of amino acids and small peptides, processes that are crucial both in...
Topics: DTIC Archive, Bowers,Michael T, University of California Santa Barbara Santa Barbara United States,...
The question of intermolecular association in the chlorodimethyltin (IV) derivatives of L-cysteine (a monohydrate) and DL-penicillamine is settled by variable-temperature tin-119m Mossbauer data between 77 and 140 or 150k, respectively. The slopes of the natural logs of the areas under the resonance are -1.58 + or - 0.1/100/K and -1.46 + or - 0.1/100/K, respectively, considerably lower than those for monomeric lattices. These data rule out an extended association through bridging amino nitrogen...
Topics: DTIC Archive, Molloy,K C, OKLAHOMA UNIV NORMAN DEPT OF CHEMISTRY, *ORGANOMETALLIC COMPOUNDS, *TIN...
The existence of an extensive chemistry centering around the triplybonded Mo-Mo and W-W units is now well established and has recently been reviewed. A firm structural base for interpreting this chemistry has been provided by more than a score of x-ray crystallographic structure determinations. Among these, however, there have been only a few pairs of molybdenum and tungsten compounds with the same or very similar sets of ligands. The comparisons afforded by such pairs are valuable in...
Topics: DTIC Archive, Chisholm,M H, PRINCETON UNIV N J DEPT OF CHEMISTRY, *SYNTHESIS(CHEMISTRY), *MOLECULAR...
Early effects in organogallium-arsenic synthetic chemistry centered on the utilization of alkane elimination reactions, as evidenced by the work of Coates and co-workers in the 1960. Through their efforts, they were able to isolate mono(arsino) gallanes and show that intermolecular As-Ga bonding to form four-coordinate gallium and arsenic dominates the structural properties of these compounds. We desired to obtain sterically hindered arsinogallanes by this method. However, we discovered that...
Topics: DTIC Archive, Wells, Richard L, DUKE UNIV DURHAM NC DEPT OF CHEMISTRY, *X RAYS, *ORGANIC COMPOUNDS,...
