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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Structure Function Relationship of Silica Polyamine Composites

Hughes, Mark Anthony 06 February 2008 (has links)
The goals of this thesis were to improve the performance of silica polyamine composites by manipulating the surface structure and to understand the relationship between, polymer structure and ligand modification of the grafted polyamine. Improvements in silica polyamine composite performance resulted from modifying silica gel with methyltrichlorosilane (MTCS) substituted for a molar fraction of reagent chloropropyltrichlorosilane (CPTCS), which has been traditionally employed. MTCS does not possess a terminal chloride group thus preventing the subsequent attachment of a polyamine to this moiety. MTCS has a smaller molecular volume than CPTCS and as a consequence greater coverage of the silica gel surface by silanes was determined by elemental analysis and NMR. An increase in the fraction of amines not attached to the surface (free amines) allowed improved mass transfer kinetics and in some cases improvements in metal ion sorption capacities of the polymer modified materials. Further, MTCS is cheaper than CPTCS thus allowing a more economically sound synthesis. As a result of an increase in free amines, silica gel polyamine composites were modified with sodium chloroacetate and other metal selective ligands in higher yield, resulting in a material with substantially improved copper ion capacities. Silica polyamine composites have also been modified with a novel series of amino acid chelating ligands for the purpose of selective extraction of heavy metals from aqueous media. The presence of the functional groups was confirmed by 13C NMR and elemental analysis. The adsorption properties of modified composites have been determined for divalent and trivalent metal ions. Cycle testing was performed to measure longevity. Selective extraction and recovery of a single metal ion from media containing multiple metal ions has been demonstrated. The structure of the polyamine used has been shown to have a significant impact on the specific selectivity of modified silica polyamine composites even when modified with the same ligand. Potential areas of application have been tested and appear promising. These include an acid mine drainage polluted stream near Helena, MT, as well as synthetic high pressure leach laterite solutions.
2

Experimental and Computational Studies on the Effect of Secondary Bonding Interactions on the Spectroscopic Properties and Reactivity of Organo-chalcogen Compounds

Elder, Philip J. 04 1900 (has links)
<p>This thesis presents the results of investigations on the application of modern spectroscopic techniques to the characterisation of secondary bonding interactions (SBIs) in selected organo-chalcogen compounds. Although the research was mostly focused on two families of compounds, ditellurides and chalcogen-substituted azodyes, the observations and conclusions are applicable to a wide variety of compounds. Because the effects of the SBIs are subtle, great care was taken to carefully distinguish contributions from other factors. DFT computational studies showed that the molecular conformation influences the electronic excitations observable in the UV-vis spectrum and the frequency of resonance in <sup>125</sup>Te NMR of organoditellurides. In the absence of protection to shield the chalcogen from intermolecular interactions, the <sup>125</sup>Te NMR chemical shift is dependent on the concentration of ditellurides; intramolecular SBIs attenuate the concentration dependency and steric protection cancels it entirely. The nature of the solvent impacts the results of both spectroscopic techniques through several mechanisms, including the solvatochromic effect, conformational changes due to the polarity of the medium and solvation. Solution <sup>125</sup>Te NMR spectroscopy is sensitive to all those contributions but, for the same reason, it cannot be applied in an unambiguous way to identify the presence of SBIs.</p> <p>Conversely, the use of intramolecular SBIs to modify the spectroscopic properties of a conjugated chromophore was investigated. Push-pull azobenzenes were derivatised with functional groups containing divalent chalcogen atoms through metathesis with a mercurated derivative of the azodye. The regiochemistry of formation of the intermediate was shown to be under kinetic control. In the chalcogen-substituted molecules, the efficiency of electron delocalisation through the SBIs was assessed by calculations of the nucleus independent chemical shift (NICS). The linear (UV-vis absorption) and nonlinear (second harmonic-generation) optical responses of the modified chromophore were investigated and interpreted in the context of the SBIs. Substitution with the chalcogen groups, and the consequent perturbation of the π-system, cause a blue shift in the first absorption maxima but little change was observed in the hyperpolarisability of the chromophore ortho-functionalised with the phenylselenenyl group. The sensitivity of the electronic spectrum to the SBI was applied to monitor the process of halide exchange in the halo-chalcogenyl derivatives of the push-pull azobenzene.</p> <p>Very strong SBIs can result in interatomic distances so short that they are difficult to distinguish from hypervalent covalent bonds. This is the situation observed in the structure of the first 2,5,8,11,1,4,7,10,3,6,9,12-tetraoxatetratelluratetrazacyclododecane. DFT calculations showed that this unusual macrocycle is stable with respect to dissociation into isotellurazole oxide and VT NOESY experiments indicate it remains intact in solution.</p> / Doctor of Philosophy (PhD)
3

Coordination chemistry of high oxidation nitrogen containing amides and heterocycles

Chua, Zhijie January 2013 (has links)
The catalytic reduction of nitrous oxide (N2O) to dinitrogen (N2) by nitrous oxide reductase (N2OR) is poorly understood. The N2O molecule is a poor ligand with relatively sparse coordination chemistry. We proposed the synthesis of probable nitrous oxide precursors which can be coordinated to transition metals prior to conversion to nitrous oxide. Nitramide, H2NNO2, 2-1, and the related nitrogen amide acids N-nitroamide 2-2, 2-3; N-nitrocarbamate 2-4, 2-5, N-nitrosocarbamate 2-6, 2-7; N-nitrosulfonamide 2-8 have been synthesized as possible nitrous oxide precursors for coordination studies with transition metals. The silver salts of the conjugate base of the nitrogen acids N-nitroamide 2-2Ag; N-nitrocarbamate 2-4Ag, 2-5Ag; N-nitrosocarbamate 2-6Ag; N-nitrosulfonamide 2-8Ag are synthesized from the reaction of the acids with Ag2CO3. Similarly the potassium salts of the nitrogen acids N-nitroamide 2-2K; N-nitrocarbamate 2-4K; N-nitrosocarbamate 2-6K; N-nitrosulfonamide 2-8K are synthesized from the reaction of the nitrogen acids with K2CO3 or CH3OK. To investigate the pi-acidity of the nitrogen acids, a series of Ir(I) complexes of the nitrogen acids, trans-Ir(η1-X)(CO)(PPh3)2, (X = nitrogen acid) N-nitroamide 3-3; N-nitrocarbamate 3-4, 3-5; N-nitrosocarbamate 3-6; N-nitrosulfonamide 3-7 are synthesized from the reaction of Vaska's complex, trans-Ir(Cl)(CO)(PPh3)2 (3-1) with the silver salts of the conjugate base of the nitrogen acids (N-nitroamide 2-2Ag; N-nitrocarbamate 2-4Ag, 2-5Ag; N-nitrosocarbamate 2-6Ag; N-nitrosulfonamide 2-8Ag). Comparative studies with the related amides, dinitramide and bistriflimide, have also been done.The oxidative addition of the nitrogen acids (N-nitroamide 2-2, 2-3; N-nitrocarbamate 2-4, 2-5) to trans-Ir(Cl)(N2)(PPh3)2 (3-2) afford the Ir(III) complexes of the nitrogen acids, Ir(η2-X)(H)(Cl)(PPh3)2, (X = nitrogen acid) N-nitroamide 3-11, 3-12; N-nitrocarbamate 3-13, 3-14. The 31P, 1H NMR and IR spectroscopic reaction monitoring profiles of the oxidative addition reactions give evidence of reaction intermediates that eventually convert to the final product. The reaction of 3-11 with CO and P(CH3)2Ph result in the formation of multiple isomers of the addition products and also phosphine substitution. Addition of methyl triflate to 3-11 in CH3CN is found to result in the substitution and loss of the nitrogen acid. The Re(I) complexes of the nitrogen acids , trans-Re(η2-X)(CO)2(PPh3)2, (X = nitrogen acid) N-nitroamide 4-8; N-nitrocarbamate 4-9; N-nitrosulfonamide 4-12 are synthesized from the reaction of trans-[Re(CH3CN)2(CO)2(PPh3)2](Y), (Y = ClO4: 4-3, BF4: 4-7) with the potassium salts of the conjugate base of the nitrogen acids 2-2K, 2-4K and 2-8K respectively. The reaction of 4-7 with N-nitrosocarbamate 2-6K at room temperature gives mostly the kinetic isomer trans-Re(η2-X)(CO)2(PPh3)2 (4-10). The same reaction at reflux conditions gives mostly a thermodynamic isomer Re(η2-X)(CO)2(PPh3)2 (4-11A). Complex 4-9 and 4-10 are found to crystallize in an unusual space group R-3 that gives a large unit cell with huge solvent channels between the Re complexes and CH2Cl2 solvate molecules. The Dimroth/amidine rearrangement of benzotriazoles has been shown to exist in solution for 5-1 by variable temperature 19F NMR. The reaction of 3-2 with the benzotriazoles 5-1 and 5-2 gives the new Ir(I) complex, trans-Ir(Cl)(η1-5-1)(PPh3)2 (5-7) and Ir(III) complex, trans-Ir(Cl)(η3-5-2)(PPh3)2 (5-8) respectively. Complex 5-7 undergoes addition and substitution reactions readily to give multiple isomers while 5-8 is inert towards nucleophiles. / La réduction de l'oxyde nitreux (N2O) en diazote (N2) par le réductase de l'oxyde nitreux (N2OR) est très peu comprise. La molécule N2O n'est pas un très bon ligand et à une coordination chimique limité. Nous proposons la synthèse de précurseurs de l'oxyde nitreux qui peuvent se coordonner aux métaux de transitions avant leurs conversions en oxyde nitreux. Nitramide, H2NNO2, 2-1, et les acides d'azotes amidés N-nitroamide 2-2, 2-3; N-nitrocarbamate 2-4, 2-5, N-nitrosocarbamate 2-6, 2-7; N-nitrosulfonamide 2-8 ont étés synthétisés en tant que de possible précurseurs de l'oxyde nitreux pour des études de coordination avec des métaux de transitions. Les sels d'argents des bases conjugués des acides d'azotes N-nitroamide 2-2Ag; N-nitrocarbamate 2-4Ag, 2-5Ag; N-nitrosocarbamate 2-6Ag; N-nitrosulfonamide 2-8Ag ont étés synthétisés par les réactions des ces acides avec Ag2CO3. Similairement, les sels de potassium des bases conjugués des acides d'azotes N-nitroamide 2-2K; N-nitrocarbamate 2-4K; N-nitrosocarbamate 2-6K; N-nitrosulfonamide 2-8K ont étés synthétisés par les réactions des ces acides soit avec K2CO3 ou CH3OK. Pour examiner l'acidité du système pi de ces acides d'azotes, des séries the complexes d'acides d'azotes d'Ir(I) trans-Ir(η1-X)(CO)(PPh3)2, (X = acide d'azote) N-nitroamide 3-3; N-nitrocarbamate 3-4, 3-5; N-nitrosocarbamate 3-6; N-nitrosulfonamide 3-7 ont étés étés synthétisés par les réactions du complexe de Vaska, trans-Ir(Cl)(CO)(PPh3)2 (3-1), avec les sels d'argents des bases conjugués des acides d'azotes (N-nitroamide 2-2Ag; N-nitrocarbamate 2-4Ag, 2-5Ag; N-nitrosocarbamate 2-6Ag; N-nitrosulfonamide 2-8Ag). Des études comparatives avec des amides reliés, dinitramide et bistriflimide, ont aussi étés faites. Les complexes de Re(I) des acides d'azotes, trans-Re(η2-X)(CO)2(PPh3)2, (X = acide d'azote) N-nitroamide 4-8; N-nitrocarbamate 4-9; N-nitrosulfonamide 4-12 ont étés synthétisés par les réactions de trans-[Re(CH3CN)2(CO)2(PPh3)2](Y), (Y = ClO4: 4-3, BF4: 4-7) aves les sels de potassium des bases conjugués des acides d'azotes 2-2K, 2-4K et 2-8K respectivement. La réaction de 4-7 avec N-nitrosocarbamate 2-6K à température de la pièce procure principalement l'isomère cinétique trans-Re(η2-X)(CO)2(PPh3)2 (4-10). La même réaction en condition de reflux procure principalement l'isomère thermodynamique Re(η2-X)(CO)2(PPh3)2 (4-11A). Les complexes 4-9 et 4-10 cristallisent dans un groupe d'espace insolite, soit R-3, qui à une grande unité cellulaire avec de larges canaux de solvant entre les complexes de Re et les molécules de solvant de CH2Cl2.Le réarrangement Dimroth/amidine des benzotriazoles ont démontré leur existence en solution pour 5-1 via la RMN 19F en température variable. Les réactions de 3-2 avec les benzotriazoles 5-1 et 5-2 donnent de nouveaux complexes d'Ir(I), trans-Ir(Cl)(η1-5-1)(PPh3)2 (5-7) et d'Ir(III), trans-Ir(Cl)(η3-5-2)(PPh3)2 (5-8) respectivement. Le complexe 5-7 subit facilement des réactions de substitution et d'addition pour donner de multiples isomères tandis que le complexe 5-8 est inerte envers les nucléophiles.
4

Some experimental studies bearing on the solubility and speciation of gold in natural waters

Vlassopoulos, Dimitrios January 1989 (has links)
No description available.
5

Platinum-based DNA binding agents as telomerase inhibitors and cancer therapeutics

Kieltyka, Roxanne January 2009 (has links)
The targeting of key processes encountered in cancer may rest in the telomeres found at the end of eukaryotic chromosome. In somatic cells, with each cellular division the length of the telomere decreases, eventually reaching a critical length that signals apoptosis. Conversely in cancerous cells, the length of the telomere is maintained by the reverse transcriptase enzyme telomerase. This enzyme operates on the long single stranded extreme 3'-terminus of the telomere that consists mostly of guanine bases. There is evidence that telomerase can be inhibited by the folding of this G-rich portion of the telomere into a quadruplex structure, consisting of a planar arrangement of four guanine bases held together by a Hoogsteen hydrogen bonded array. Therefore, it is of great interest to create small molecules that bind strongly and preferentially to the G-quadruplex DNA motif for telomerase inhibition as a cancer therapy. Thus far, there have been many elegant studies on organic G-quadruplex binders that have appeared, but examples involving inorganic complexes are rare. Implementation of transition metals in these scaffolds provides the opportunity to generate G-quadruplex binders of multiple geometries beyond those that carbon can access. Comparatively speaking, introduction of metals into these scaffolds can lead to simplified syntheses of these binders over their organic counterparts with generation of compound libraries able to selectively target G-quadruplex DNA. A first generation of phenanthroimidazole platinum(II) complexes were synthesized, containing large π-surfaces that can bias their binding to G-quadruplex DNA. In comparison to a bipyridine platinum(II) complex, binding affinity and selectivity for the intermolecular Gquadruplex, (T4G4T4)4 is compared through UV-Vis titrations, thermal denaturation, competitive dialysis, circular dichroism and molecular modeling. In an attempt to place our stu / Le ciblage des mécanismes clés du cancer pourrait se situer au niveau des télomères positionnés à l'extrémité du chromosome eucaryote. La télomère raccourcis lors de la division des cellules somatiques pour atteindre éventuellement une longueur critique signalant l'apoptose. Chez les cellules cancérigènes, la longueur du télomère est maintenue par la télomérase. Cette enzyme fonctionne spécifiquement sur le simple brin d'ADN situé à l'extrémité 3'-terminal du télomère, qui est composé en majeur partie de guanines (G). Il existe des preuves que l'activité de la télomérase peut être inhibée par le repliement de cette région du télomère riche en bases G. La structure quadruplexe ainsi formée est composée d'un arrangement planaire de quatre bases guanines tenu ensemble par une pléiade de liaison d'hydrogène de Hoogsteen. Par conséquent, il est de grand intérêt pour le traitement thérapeutique du cancer de créer de molécules qui ont la capacité de se lier solidement et préférentiellement à la structure G-quadruplexe de l'ADN. Il y a eu jusqu'à présent de nombreuses études exécutées sur les molécules organiques se liant au motif G-quadruplexe. Les exemples relatifs aux ligands composés d'éléments inorganiques sont par contre plus rares. La mise en oeuvre des métaux de transition dans ces échafaudages moléculaires offre l'opportunité de générer des ligands G-quadruplexe de géométries inaccessible aux ligands organiques. Comparativement, l'introduction des métaux de transition peut simplifier la synthèse des ligands G-quadruplexe et mener à l'élaboration d'une bibliothèque de composés ayant la capacité de cibler sélectivement le motif G-quadruplex. Une première génération de complexes de phenanthroimidazole de platine (II) a été synthétisée, ayant de larges surfaces-π pouvant être ajusté lors de la liaison avec le motif G-quadruplexe.
6

Investigations towards an overall mechanism for sulfur extrusion. The importance of diatomic sulfur

Williams, Charles R. (Charles Ralph) January 1991 (has links)
Several reaction systems have been investigated as possible sources of diatomic sulfur (S$ sb2$). Dialkoxy disulfides have been shown to thermally decompose with the formation of sulfur likely as S$ sb2$ which was successfully trapped in modest yield. Several other systems have been shown to decompose with a likely S$ sb2$ intermediate. / The chemistry of the chloro(triphenylmethyl)sulfides was studied. The X-ray crystal structures of the first chlorodisulfide and chlorotrisulfide were obtained. The chlorotriphenylmethyl sulfides were found to decompose in the presence of 1,3-dienes to yield products which are consistent with the trapping of diatomic sulfur. The reactions of the chloro(triphenylmethyl)sulfides were examined and used to prepare a series of mixed sulfides containing 1-4 sulfurs. A novel extrusion of sulfur in the reaction of chloro(triphenylmethyl)monosulfide with thiocarbonyl compounds was investigated. The thermal decomposition of the sulfides as solids and in solution were examined. / The solvent dependent desulfurization of sulfenic sulfonic thioanhydrides was investigated in the anticipation of discovering a diatomic sulfur intermediate. The extrusion was shown to involve the concatenation of sulfur atoms until a stable sulfur ring could be extruded. / The X-ray crystal structure of bis(triphenylmethyl)disulfide was determined and was discussed in relation to other hindered disulfides.
7

The sequential insertion of carbon monoxide and imines into nickel-carbon [sigma]-bonds : synthesis, reactivity and multi-component couplings

Davis, Jason L. January 2005 (has links)
The development of new methods of generating alpha-amino acid derivatives via multi-component reactions remains an important challenge. The primary goal of this study is to develop new transition metal-mediated routes to synthesize these alpha-amino acid derivatives using combinations of simple reagents, such as imines, carbon monoxide, acid chlorides and organotin reagents. The proposed approach requires the sequential insertion of imine and carbon monoxide into late transition-metal sigma-bonds, as well as the further reactivity of the products. / In chapter 2, the ability of the nickel complex L2Ni(CH 3)N(R)=C(H)R'+X- (L2 = chelating nitrogen ligands, X- = non-coordinating counteranion) to mediate the insertion of imines is examined. Although L2Ni(CH3)N(R)=C(H)R' +X- does not undergo direct imine insertion into the Ni-CH3 bond, the addition of CO leads to the generation of the novel nickel complex (L2)Ni[n2-CH(R')NRCOCH 3]+X- via the insertion of imine into the nickel-acyl bond of L2Ni(COCH3)N(R)=C(H)R' +X-. This demonstrates as proof of concept, that these nickel complexes can mediate the sequential insertion of CO and imine into nickel-methyl bonds, in direct analogy to well known CO/olefin insertions. Further reactivity studies have demonstrated that the amide bound nickel chelates generated via the sequential insertion of CO and imines are generally inert towards subsequent migratory insertion with CO, imine and olefins (Chapter 3). These complexes are also inert towards auxiliary ligand exchange or amide de-chelation, with both mono- and bidenate nitrogen and phosphine ligands. / Studies involving the use of imines and alkenes as interchangeable insertion substrates, (Chapter 4) resulted in the first example of a metal mediated cyclocarbonylation incorporating imine as a formal insertion substrate. Based on these studies, one-pot sequential insertion cascade of CO, olefin, a second unit of CO, and imine was developed for the synthesis of 5 and 6 membered lactams. In addition, the competitive insertion propensity of imines and alpha-olefins was examined, and clear steric and electronic effects were identified. / The isoelectronic palladium-bound amide complexes, generated via the oxidative addition of N-acyl iminium salts (R(H)C=N(R')COR") to Pd2(dba) 3·CHCl3 can undergo a Stille-tye coupling with organotin reagents to generate alpha-substituted amide derivatives (Chapter 5). This reactivity was extended into a convenient and general one-pot synthesis of alpha-substituted amides and N-protected amines by a palladium-catalyzed three-component coupling of imines, acid chlorides or chloroformates, and organotin reagents. Mechanistically, this process provides an oxidative addition/reductive elimination-based alternative to nucleophilic approaches to C-C bond formation with imines, in which the imines are activated towards addition to palladium by RCOCl.
8

Synthesis, structural and solid-state, multinuclear magnetic resonance studies of some manganese and nickel complexes containing silicon, tin, lead and phosphorus ligands

Christendat, Dharamdat. January 1998 (has links)
A number of organometallic complexes involving manganese, bonded to silicon, tin, lead and phosphorus ligands, and nickel, bonded to various trialkylphosphine ligands, has been synthesized and their crystal structures, vibrational, and multinuclear magnetic resonance spectra have been obtained. The FT-IR and FT-Raman spectra of the manganese carbonyl compounds in the carbonyl region (2200--1850 cm--1) have been assigned. Solid-state, CP-MAS, 13C, 29Si, 31P, 117Sn, 119Sn and 207Pb NMR spectra of substituted pentacarbonylmanganese(I) and tetracarbonylmanganese(I) complexes feature asymmetric sextets, whereas those containing a group 14 (IVA) element bridging two pentacarbonylmanganese(I) moieties show asymmetric sextets. The uneven splitting arises from spin-spin coupling and second-order quadrupole-dipole effects, which are not eliminated by magic angle spinning. The solid-state NMR spectra of the manganese complexes have been analyzed to give the isotropic chemical shifts, the chemical shift tensors, one-bond spin-spin coupling constants, 55Mn nuclear quadrupole coupling constants, effective dipolar coupling constants and the anisotropies; in the spin-spin coupling for each complex. The results provide new insights into the relationship between spin-spin coupling and quadrupolar coupling in bimetallic complexes involving a quadrupole transition-metal and a spin-1/2 nucleus. / For the para-substituted triaryltin complexes, the 13C, 55Mn and 119Sn chemical shifts and one-bond spin-spin constants in solution show excellent correlations with pairs of substituent constants (sigmaI, sigmaR). However, there is no correlation of the chemical shifts or spin-spin coupling with either Hammett (sigmaP) or Taft (sigmaP o) constants or the Mn-Sn bond lengths, rMn-Sn. The results obtained from dual substituent parameter (DSP) analysis indicate that both resonance effects (sigmaR) and inductive effects (sigma I) are important in determining the NMR parameters. / Crystal structures and high-resolution solution and solid-state 31P NMR spectra were obtained for several dihalobis(trialkylphosphine)nickel(II) complexes. The crystal structures and NMR results indicate that these complexes are trans square-planar in the solid-state. The chemical shifts and shift tensors were obtained and found to vary with the electronic properties of the halogens. The 31P isotropic chemical shifts in the solution spectra of dibromo- and diiodiobis(tribenzylphosphine)nickel(II) are very different from those found for the solid-state, and chemical exchange effects were observed in all spectra. The mechanism of exchange appears to involve the formation of dimers with bridging halides.
9

Multiple scattering calculations of large inorganic systems

Berksoy-Bölük, Ebise Mualla January 1989 (has links)
Self-consistent field multiple scattering (SCF-MS) calculations have been performed on the aluminium trihalides, AlX$ sb3$ (X = F, Cl, Br, I) and their dimers, Al$ sb2$X$ sb6$ and on the large organometallic compounds diphenyltin(IV) dichloride and diphenyllead(IV) dichloride monomers and dimers. All these molecules have nuclear quadrupole resonance (n.q.r.) active nuclei and strong or weak intermolecular halogen interaction. In addition, diphenyltin(IV) dichloride has a Mossbauer active $ sp{119}$Sn nuclei to study the isomer shift and quadrupole splitting. Calculations used the Vosko-Wilk-Nusair(VWN) exchange-correlation potential in addition to Slater's X$ alpha$ exchange potential and also a quasi-relativistic wavefunction for the heavy nuclei in these molecules. The VWN and X$ alpha$ n.q.r. results are compared for the aluminium trihalides. The non-relativistic and relativistic calculations which are very important for the hyperfine interactions are compared for diphenyltin(IV) dichloride and the calculated relativistic Mossbauer isomer shift and quadrupole splitting agree well with experiment. The electric field gradients, which are very sensitive to the charge distribution around the nuclei in the molecules, gave very important information, using the n.q.r. and Mossbauer results, about the intermolecular halogen interactions in these molecules, supporting the conclusions arrived at using the one-electron energies and the HOMO-LUMO gap, and from the wavefunction contours and density maps. The relative Lewis acidity order and ionization potentials are also studied in the aluminium trihalides. Qualitative interpretation and agreement with experiment were found whenever experiment was available. Electronic structure and n.q.r. comparison of the diphenyltin(IV) dichloride and diphenyllead(IV) dichloride monomers and dimers lead to the conclusion that the diphenyltin(IV) dichloride is a monomer and the diphenyllead(IV) dichloride is a polymer.
10

Kinetics of the chemiluminescent reaction between ozone and nitric oxide.

Sangster, James Malcolm. January 1966 (has links)
In early work this chemiluminescence was confused with that from the oxygen atom - nitric oxide reaction. Indeed it has turned out that their spectra and mechanisms are quite similar, so that an understanding of the 0-NO reaction (which was investigated first) will facilitate understanding of the O3-No reaction. [...]

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