This work focuses on an examination of the high-accuracy extrapoloated ab initio thermochemistry (HEAT) protocol of determining molecular atomization energies. The HEAT protocol does not utilize experimental data or empirical scaling effects. The accuracy of the approach is tested via comparison to ATcT data, and all molecules fall within 1 kcal/mol of accepted values. There are several important points to note about this treatment: namely, that we have used atomic natural orbital (ANO) basis sets for the calculation of the zero point energy and that we have made determinations for larger molecules than previously done with HEAT. The molecules in this paper were chosen to provide benchmark numbers for the homodesmotic reaction heirarchy as described by Wheeler et al.[3] The relative accuracy of the approach is considered, as well as a discussion of possible remaining sources of error. / text

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Thesis (Ph. D.)--University of Sydney, 2003. / Title from title screen (viewed Apr. 28, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Chemistry, Faculty of Science. Includes bibliographical references. Also available in print form.

Thesis (Ph. D.)--Michigan State University. Program in Cell and Molecular Biology , 2006. / Title from PDF t.p. (viewed on June 19, 2009) Includes bibliographical references. Also issued in print.

Includes bibliographical references (p. 46-47). / "Physics Chemsitry" -t.p.

Proefschrift--Universiteit van Amsterdam. / "Stellingen" [2 ℓ.] inserted. "References": p. 59.

Orientador: Claudio Airoldi / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-11T03:37:39Z (GMT). No. of bitstreams: 1 Petrucelli_GiovanniCavichioli_D.pdf: 3020271 bytes, checksum: 5a4f7f1eb6690fc674c3035426ab508e (MD5) Previous issue date: 2008 / Resumo: O composto lamelar magadeíta foi hidrotérmicamente sintetizado na forma (Na2Si14O29.9H2O) [Namag], que ao ser tratado com HCl 0.10 mol dm gerou [Hmag]. O nanocomposto hidratado ácido silícico lamelar magadeíta [Hmag] (H2Si14O29.2H2O), foi utilizado na intercalação de alquilaminas polares de fórmula geral H3C(CH2)nNH2 (n=1-6) em solução aquosa. A distância interlamelar (d) original da [Hmag] de 1150 pm, apresenta aumento com a intercalação, dando correlações com o número de átomos carbonos da amina alifática (nc): d = [(1313±15) + 20±3)]nc. A quantidade de amina intercalada (Ns) diminui com o aumento de nc: Ns = [(5,87±0,12) ¿ (0,43±0,03)]nc. Os resultados de titulação calorimétrica deram correlações termodinâmicas com a entalpia: DintH = -[(24,45±0,49) ¿ (1,91±0,10)]nc e d = [(1576±16) ¿ (11±1)]DintH. Os valores negativos da energia livre de Gibbs e positivos para entropia deram as correlações: DintG = -[(22,3±0,2) ¿ (0,5±0,1)]nc and DintS = [(6±1) + (5±1)]nc, respectivamente. A forma ácida [Hmag] foi modificada quimicamente com [3- aminopropiltrimetoxissilano (1N), N-3-trimetoxissililpropiletilenodiamina (2N), N-3-trimetoxissililpropiletilenotriamina (3N) e 3-mercaptopropiltrimetoxissilano (1S)]. Os materiais sintetizados foram caracterizados por difração de raios-X, espectroscopia na região do infravermelho, RMN no estado sólido de Na, Si and C, área superficial, volume de poro e termogravimetria. A quantidade de agente sililante incorporada foi determinada por análise elementar resultando em: (2,34±0,18), (1,96±0,18), (1,25±0,11) e (1,45±0,12) mmol g, respectivamente. O número de moles dos cátions divalentes adsorvidos (Co, Ni, Cu, Zn, Cd e Hg) foi determinado através do processo de batelada e ajustado ao modelo de Langmuir. Os efeitos térmicos da interação cátions centros básicos existentes nas cadeias xiv pendentes foram determinados por titulação calorimétrica na interface sólido/líquido. Os valores entálpicos são exotérmicos, de energia livre de Gibbs e entropia negativos e positivos, respectivamente, indicando que os efeitos interativos são termodinamicamente favorecidos. Os espectros de XANES e EXAFS indicam que átomos de cobre são adsorvidos por 1N e 1S resultando em octaédros com diferentes graus de distorção. O Cu-1Nmag apresenta similaridade estrutural ao CuO de acordo com o padrão de Cu(OH)2 com quatro ligações equatoriais e duas axiais. A simulação de EXAFS para a segunda esfera de coordenação está associada ao efeito de interação com um cátion de cobre adjacente, sugerindo que o cobre está coordenado como cluster multinucleares, como resultado de uma precipitação inicial de monômero, seguida pela formação de um cluster com ponte de hidróxido / Abstract: Layered compounds magadiite was hydrothermically synthesized (Na2Si14O29.9H2O) [Namag] end treated with HCl 0.10 moldm gerou [Hmag]. The hydrated lamellar nanocompound acidic silicic magadiite [Hmag] (H2Si14O29.2H2O), was used as host for intercalation in aqueous solution of polar alkylmonoamine molecules of the general formula H3C(CH2)nNH2 (n=1-6). The original interlayer distance (d) of 1150 pm, by [Hmag], increases after intercalation, resulting on values correlated with the number of the carbons atoms of aliphatic amine (nc): d = [(1313±15) + 20±3)]nc. The amount of intercalated amines (Ns) decreased as nc increased: Ns = [(5,87±0,12) ¿ (0,43±0,03)]nc. The calorimetric titration results for enthalpy data gave thermodynamic correlations:: DintH = -[(24,45±0,49) ¿ (1,91±0,10)]nc and d = [(1576±16) ¿ (11±1)]DintH. The negative Gibbs energy values and positive entropies also presented the correlations: DintG = -[(22,3±0,2) ¿ (0,5±0,1)]nc and DintS = [(6±1) + (5±1)]nc, respectively. The acides [Hmag] form was chemically modified with: [3- trimethoxysily(propylamine)] (1N), [N-(3-trimethoxysilil)propyl)etylenediamine] (2N), [N-3-trimethoxysililpropyl(etylenetriamine)] 3N and [3-trimetoxysilmercaptopropyltrimethoxysilane] (1S). The synthesized materials were characterized by X-ray powder diffraction, infrared spectroscopy, Na, Si and C, NMR in solid state, surface area, pore volume and thermogravimetry. The amounts of silylating agent immobilized were determined from elemental analyses to give: 2.34±0.18, 1.96±0.18, 1.25±0.11 and 1.45±0.12 mmol g, respectively. The number of moles divalents cations (Co, Ni, Cu, Zn, Cd and Hg) adsorbed was obtained for batch wise procedure and the data was adjusted to Langmuir model. xvi The thermal effects of cation basic centers on pendant chains interactions were obtained through calorimetric titration at the solid/liquid interface. The exothermic enthalpy, the negative Gibbs free energy and positive entropy values, are in agreement are thermodynamically favorable for these interaction. The XANES and EXAFS spectra indicated that copper atoms were adsorbed on 1N and 1S layered materials resulting in octahedron structure with different degree of distortions. Cu- 1Nmag resembled the CuO unit from Cu(OH)2 model with similar four equatorial and two axial Cu-O distances. The EXAFS simulation of the second sphere associated with Cu-Cu bond for materials that suggested the coordinated metal in multinuclear clusters on the surface, as a result of the initial monomer precipitation that growth from the formation hydroxo-bridged clusters / Doutorado / Quimica Inorganica / Doutor em Ciências

pK_n values for step-wise dissociation of protons from the protonated ligands (glycine, α-amino isobutyric acid, sarcosine and theonine) were determined potentiometrically with a Beckman Model GS pH meter in aqueous solution at 10, 20, 30 and 40° C. Log K values for step-wise interaction of glycine, α-amino isobutyric acid, sarcosine and threonine with copper(II) ion were also determined potentiometrically with a pH meter at 10, 20, 30 and 40° C. The standard free energy of formation for the step-wise interaction of copper(II) with each of the above ligands was calculated from the values of log K. Enthalpy and entropy changes were calculated for each of the above reactions at 20° C. Measurements of pH were obtained at several ionic strengths for each metal io-ligand system at each temperature. It was assumed that the zwitterion has no charge. The hydrolysis of copper(II) ion and the liquid junction potential were assumed to be negligible. Log K_1 and log K_2 values for the copper(II) chelate of α-amino isobutyric acid are lower than those of glycine at 10 20° C. but higher at 30 and 40° C. This may be related to the positive inductive effect and the steric effect of methyl groups. The large decrease in the log K values of the copper(II) chelate of sarcosine is probably due to two effects, namely, steric and hydration. These two effects counteract the positive inductive effect introduced by the methyl group on the nitrogen and actually decrease its basic strength and thus decrease the bond strength between nitrogen and copper. THe decrease in the log K values of the copper (II) chelate of threonine is explained by the presence of the hydroxyl group which increases the acid strength of the NH_3^+ group and decreases its electron donating power. This is probably due to the hydrogen bonding between the hydrogen of the hydroxyl group and nitrogen of the amino group. Values of log K for the copper(II) chelate of each ligand decrease with the increase in the temperature, indicating that the entropy effect is greater at a lower temperature than at a higher temperature. Calculations of n, [A^-] and log K were carried out on an IBM 650 Computer.