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Halogen and nitrogen containing compounds play a key role in the atmospheric chemistry of the Earth. Through a mixed computational and experimental approach, the kinetics of these compounds with radicals common to the atmosphere have been explored. Using fundamental measurements such as the IR absorption cross-section, the rate constants of atmospheric reactions and the properties of product molecules have been derived. These results have been further extended to environmental applications such as the Global Warming Potential for a species. The present results can be used as a calibration for further experiments and as checks on computational predictions of environmental properties. Such modeling can aid in the development of future industrial reagents that are less hazardous to the atmosphere.

A presente tese relata, em sua primeira parte, o estudo de reatividade das reações competitivas de Michaelis-Arbuzov e Perkow de algumas &#945-haloacetofenonas-orto e meta-substituídas [o- e m-Y-&#934-C(O)CH2-Hal] (Hal = CI, Br e I; Y = OMe, Me, H, F, CI, Br e NO2) com o trietilfosfito. Estas reações foram acompanhadas por cromatografia a gás e observou-se que no caso das reações das &#945-bromoacetofenonas-meta-substituídas as proporções dos produtos de Michaelis-Arbuzov e Perkow, cetofosfonato e enolfosfato respectivamente, estão diretamente relacionadas à constante &#963m, enquanto que nas &#945-cloro e &#945-iodoacetofenonas-orto-substituídas não foram observados os efeitos dos substituintes. Entretanto, nas &#945-bromoacetofenonas- orto-substituídas, verificou-se uma forte dependência da constante &#963I dos substituintes com as proporções relativas dos produtos formados. Na segunda parte desta tese, foi realizado um estudo conformacional de 7 séries de &#945-heteroacetofenonas-orto e meta-substituídas [o- e m-Y-&#934-C(O)CH[X]-P(O)(OEt)2] (X = H, SMe, S(O)Me e SO2Me; Y = OMe, Me, H, F, CI, Br e NO2), através da espectroscopia no infravermelho apoiada por cálculos ab initio HF/6-31 G**. Foi observada, para a maioria dos casos, a presença de um ou dois confôrmeros em solução, onde na maioria dos casos a conformação mais estável é a gauche (sin-clinal) e a segunda mais estável é ou cis (sin-periplanar) ou gauche (anti-clinal). Na série das &#945-metiltio-&#945-dietoxifosforilacetofenonas-orto-substituídas não foi possível efetuar o estudo conformacional devido a enolização presente nestes compostos. Nas &#945-metilsulfinil-&#945-dietoxifosforilacetofenonas-meta-substituídas verificou-se através das espectroscopias no infravermelho e ressonância magnética nuclear, a presença de um equilíbrio diastereomérico. / This thesis reports the study of the reactivity of the competitive Michaelis- Arbuzov and Perkow reactions of some orto- and meta- substituted &#945-haloacetophenones (I) [o- and m-Y-&#934-C(O)CH2-Hal] (Hal = CI, Br e I; Y = OMe, Me, H, F, CI, Br and NO2) with triethyl phosphite, by gas chromatography, and the conformational analysis of some orto- and meta-substituted &#945-heteroacetophenones (II) [o- and m-Y-&#934-C(O)CH[X]-P(O)(OEt)2] (X = H, SMe, S(O)Me and SO2Me; Y = OMe, Me, H, F, Cl, Br and NO2), by means of infrared spectroscopy and ab initio HF/6-31 G** computations. For reactions involving meta-substituted &#945-bromoacetophenones and triethylphosphite it was found a good correlation between the ketophosphonate / enolphosphate ratio (K/E) and the &#963m constant. The (K/E) ratios obtained from the reaction of the orto- substituted &#945-chloro- and &#945-iodo-acetophenones and triethylphosphite did not show a clear trend with any substituent constant. However, a good correlation between the (K/E) ratio and the &#963I constant was obtained in the case of the reaction involving the orto-substituted &#945-bromoacetophenones and triethylphosphite. The vco infrared analysis in general compares well with the ab initio calculations which showed the occurrence of one or two stable conformations for compounds of series (II), being the gauche (syn-clinal) the most stable and the cis (syn-periplanar) or the gauche (anti-clinal) the second one. The vco IR analysis of the orto-substituted &#945-methylthio-&#945-diethoxyphosphorylacetophenone series was precluded due to its strong enolization. As for the meta-substituted &#945-methylsulfinyl-&#945-diethoxyphosphoryl-acetophenones the IR and NMR spectroscopies along with the ab initio computations showed the ocurrence of a diastereomeric equilibrium both in gas and in solution.

Made available in DSpace on 2017-07-24T19:38:06Z (GMT). No. of bitstreams: 1 CAROLYNE BRUSTOLIN BRAGA.pdf: 3440444 bytes, checksum: b267696c3988d456840fac4ec2aeded0 (MD5) Previous issue date: 2012-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this study was approached the conformational study of dopamine, L-dopa and L-dopaquinone, in their neutral and protonated forms, by theoretical calculations and NMR and IR spectroscopies. The interest in evaluate the conformational equilibrium of these compounds was obtained by the fact that there are no reports in the literature about them at this level of theory, considering that are compounds with high biological importance. The theoretical calculations were performed at HF/6-311++G(d,p) level of theory, available in the programs package GAUSSIAN 03. These calculations determined the energies and geometries of most stable conformers in the isolated phase and in aqueous solution. For some compounds, the analysis of hyperconjugatives effects by NBO calculations also showed that some orbital interactions stabilize the system. For protonated dopamine, by 1H NMR, it was not possible to associate the solvent or temperature effects with possible changes in populations of conformers. In the case of two forms of L-dopa, the behavior of the couplings constants 3JHH in different solvents and temperatures could not tell us if there was variation in the populations with change of polarity of the medium. However, their values allowed affirm that the predominant form at equilibrium in solution is the trans, in agreement with theoretical data obtained. The carbonyl stretching bands, in IR spectrum, in fundamental region, could not determine the variations in the populational equilibrium, but a significant asymmetry and width of these bands showed that the equilibrium is composed of multiple conformations, such as this case. Finally, electrostatic potential maps were used to demonstrate in the most stable conformers which regions of higher and lower electron density. Keywords: Conformational analysis. Theoretical calculations. NMR Spectroscopy. / Abordamos neste trabalho um estudo conformacional da dopamina, L-dopa e L-dopaquinona, nas suas formas neutras e protonadas, por meio de cálculos teóricos e das espectroscopias de RMN e IV. O que despertou o interesse em avaliar o equilíbrio conformacional desses compostos foi o fato de não existirem relatos na literatura sobre os mesmos com este tipo de nível de teoria, visto que são compostos com grande importância biológica. Os cálculos teóricos foram efetuados com o nível de teoria HF/6-311++G(d,p), disponíveis no pacote de programas GAUSSIAN 03. Por meio deles, determinaram-se as energias e geometrias dos confôrmeros mais estáveis na fase isolada e em solução aquosa. Para alguns compostos, a análise dos efeitos hiperconjugativos por meio dos cálculos de NBO também indicou que algumas interações de orbitais presentes estabilizam o sistema. Para a dopamina protonada, através da RMN de 1H, não foi possível relacionar o efeito do solvente nem da temperatura com possíveis mudanças nas populações dos confôrmeros. No caso das duas formas da L-dopa, o comportamento dos acoplamentos 3JHH em diferentes solventes e diferentes temperaturas não pôde nos dizer que houve variação de população com a mudança de polaridade do meio. Entretanto, seus valores permitiram afirmar que em solução a forma predominante no equilíbrio é a trans, corroborando com os dados teóricos obtidos. Com espectros no Infravermelho na região do fundamental do estiramento da carbonila, para a L-dopa, novamente não pudemos verificar a variação de população no equilíbrio, mas a significativa assimetria e largura destas bandas permitiu verificar que o equilíbrio está composto por vários confôrmeros, como é o caso. Finalmente, fez-se o uso de mapas de potencial eletrostático para demonstrar nos confôrmeros mais estáveis quais as regiões de maior e menor densidade eletrônica.

Made available in DSpace on 2017-07-24T19:38:08Z (GMT). No. of bitstreams: 1 Taissa Adriana Costin.pdf: 4929780 bytes, checksum: 1674ff97dbc8df45d3aedf8e6744fdde (MD5) Previous issue date: 2013-03-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Due to the great importance of the aspartic acid, since it is found in the Dimethyl N-acetylaspartate in high concentrations in the urine of patients with different neurological problems, an example is Canavan disease, which has been associated with elevated concentrations of N-acetylaspartate in cerebrospinal fluid, it inspired the interest of studying conformational equilibrium of compounds with structures similar to Dimethyl N-Acetylaspartate. The focus of this study was to research the compound structural Dimethyl N-acetylaspartate (NAA) and their derivatives Dimethyl N-Methylaspartate (NMA) and Dimethyl N, N- Dimethylaspartate (NDA). The principle was to establish the most stable geometries and populations of conformers involved in the equilibrium phase and isolated in solution. To perform DFT calculations, we used the Gaussian 03 software package. The potential energy surfaces (SEPs) were obtained with B3LYP/6-311G level of theory and the points of lowest energy, made possible as more stable geometries which were optimized with the level of theory B3LYP/cc-PVTZ. For the structure of the NAA, we found seven more stable geometries. The majority conformer of NAA showed a population of 31,9% on balance. For the structure of the NMA met ten most stable geometries. The majority conformer population showed a 35,4% on the balance. As for the structure of the NDA, it also met seven most stable geometries. The majority conformer population showed a 46,5% on the balance. Besides the equilibrium phase alone was evaluated with these structures and solvation calculations it was observed that populations of conformers were changed, but the same major conformer being isolated majority remained in solution. In order to compare the theoretical data with experimental data, these compounds were synthesized therefore performed NMR spectroscopic analysis which analyzed the coupling constants 2J and 3J and IV, held the deconvolution of the carbonyl band. / Devido à grande importância do ácido aspártico, já que o mesmo é encontrado na forma de N-Acetilaspartato em concentrações elevadas na urina de pacientes com diferentes problemas neurológicos, um exemplo é a doença de Canavan, a qual vem sendo associada a concentrações elevadas de N- Acetilaspartato no fluido cerebroespinal despertou-se o interesse em estudar o equilíbrio conformacional de compostos com estruturas semelhantes ao mesmo. O foco deste estudo foi realizar uma investigação estrutural do composto N-Acetilaspartato de dimetila (NAA) e dos seus derivados, N-Metilaspartato de dimetila (NMA) e N,N-Dimetilaspartato de dimetila (NDA), determinando as geometrias mais estáveis e as populações dos confôrmeros envolvidos no equilíbrio na fase isolada e em solução. Para a realização dos cálculos DFT, utilizou-se o pacote de programas Gaussian 03. As superfícies de energia potencial (SEPs) foram obtidas com nível de teoria HF/6-311G e os pontos de menor energia, assumidos como possíveis geometrias mais estáveis, as quais foram otimizadas com o nível de teoria B3LYP/cc-PVTZ. Para a estrutura do NAA, encontrou-se sete geometrias mais estáveis. O confôrmero majoritário do NAA apresentou uma população relativa de 31,9% do equilíbrio. Para a estrutura do NMA, encontrou-se dez geometrias. O confôrmero majoritário apresentou uma população relativa a 35,4% do equilíbrio. No caso da estrutura do NDA, obteve-se também sete geometrias. O confôrmero majoritário apresentou uma população relativa a 46,5% do equilíbrio. Além do equilíbrio em fase isolada, avaliou-se estas estruturas com cálculos de solvatação e observou-se que as populações dos confôrmeros foram alteradas, porém os mesmos confôrmeros majoritário em fase isolada, continuaram majoritários em solução. A fim de confrontar os dados teóricos com dados obtidos experimentalmente, estes compostos foram sintetizados e, portanto realizadas análises espectroscópicas de RMN a qual analisou-se as constantes de acoplamento 2J e 3J e no IV, realizou-se a deconvolução da banda da carbonila.

The [2,3]-sigmatropic rearrangement is a pericyclic reaction of great synthetic utility to organic chemists. Within the scope of this reaction exist some cases in which the product corresponding to a [1,2] rearrangement is formed, despite the fact this is a forbidden process. Generally this is explained by a radical dissociation-recombination pathway; however, studies into the failure of transition state theory and the necessity to incorporate dynamic effects into mechanistic theory lead us to believe such products may arise from these phenomena. In particular, the possibility that many of these products result from an “unsymmetrical bifurcating surface” in the potential energy landscape is intriguing. To investigate this possibility, the Sommelet-Hauser rearrangement of N-allyl-N,N-dimethylglycine methyl ester was explored. The combined use of experimental and theoretically predicted kinetic isotope effects (KIEs) has been previously shown to deliver great mechanistic insight into reactions. The combination of these techniques, however, has found little employ in studying [2,3] rearrangements. This combination was used to study this reaction, using the Singleton method for determining small heavy-atom isotope effects. Resulting experimental KIEs suggest the reaction proceeds by an asynchronous, concerted, early transition state, and is relatively exothermic. This agrees with previous studies and Hammond’s postulate. Predicted theoretical KIEs are in good agreement with experimental KIEs, and the associated transition structure confirms the results suggested by experiment. Interestingly, as calculations proceed from gas phase to solvent models, the activation barrier of the reaction increases, while its exothermicity decreases. The energy difference determined between the lowest and second lowest energy transition structures decreases to 0.81 kcal/mol in the PCM model, so we cannot exclude the contribution of this transition structure to the reaction. However, qualitative results from the associated KIEs and energetics are consistent with the lowest energy transition structure. This reaction does not seem to afford the [1,2] product, and most likely dynamic effects are insignificant in determining product distribution. However, the study has validated, with respect to this body of reactions, both the use of the Singleton method for KIE determination and the combination of these experimental and theoretical techniques.

As part of this project and in preparation for future experimental studies of gas-phase ion-molecule reactions, extensive modification and characterization of the crossed molecular beam machine in the Department of Chemistry, University of Canterbury has been carried out. This instrument has been configured and some preliminary testing completed to enable the future study of gas-phase ion-molecule collisions of H⁺₃ and Y⁻ (Y = F, Cl, Br) with dipole-oriented CZ₃X (Z = H, F and X = F, Cl, Br). Theoretical calculations (ab initio and density functional theory) are reported on previously experimentally characterized Na + CH₃NO₂, Na + CH₃NC, and K + CH₃NC systems, and several other systems of relevance. All gas-phase experimental and theoretical studies have the common theme of studying collision orientation dependence of reaction under singlecollision conditions. Experimental measurements, theoretical simulations and calculations are also reported on some selected ferrous (Fe²⁺) high-spin (S=2) crystals, in an attempt to resolve microscopic contributions of two fundamental macroscopic tensor properties: the electric-field gradient (efg); and the mean square displacement (msd) in the case when more than one symmetry related site of low local point-group symmetry contributes to the same quadrupole doublet. These determinations have been made using the nuclear spectroscopic technique of Mössbauer spectroscopy, and complemented with X-ray crystallographic measurements.

Made available in DSpace on 2016-06-02T20:36:51Z (GMT). No. of bitstreams: 1 5776.pdf: 5076253 bytes, checksum: 2b1fe288412167608c8d92ffa4efdf38 (MD5) Previous issue date: 2014-02-26 / Universidade Federal de Minas Gerais / The incessant search for better materials with diverse applications and increasingly smaller size has been performed by numerous research groups. The calcium sulfide semiconductors have been the focus of study for applications in this field. This semiconductor can be applied in to various devices due to photo- and electroluminescent properties. The technological advances in computational area allowed the improvement in different research fields such as Theoretical Chemistry, which is able to enhance, induce and predict new material properties with potential technological applications. The objective of this project was to apply the Theoretical Chemistry, in order to provide a better understanding of the chemical and structural properties of the calcium sulfide. Models and computer simulations were developed to analyze the electronic and structural properties of this material in crystal and surface level. The results were compared to the experimental data obtained by the microwaveassisted solvothermal method and discussed in terms of band structure, density of states and of charge map. With respect to the lattice parameter and internal coordinates, the theory used show good results, confirming the data obtained experimentally. Theoretical band gap values were also similar to the experimental values and indicated direct transition in all models studied. / A busca incessante por melhores materiais com aplicações diversas e tamanhos cada vez menores tem sido realizada por inúmeros grupos de pesquisa. O semicondutor sulfeto de cálcio tem sido foco de estudos para aplicações nesse campo. Esse semicondutor pode ser aplicado em vários dispositivos devido às suas propriedades foto e eletroluminescente. O crescente avanço tecnológico na área computacional permitiu o aprimoramento em diferentes campos de pesquisa, ressaltando a Química Teórica que é capaz de aprimorar, induzir e prever novas propriedades em materiais com potenciais aplicações tecnológicas. O objetivo deste projeto foi aplicar a Química Teórica, a fim de proporcionar uma melhor compreensão das propriedades químicas e estruturais do sulfeto de cálcio. Foram desenvolvidos modelos e simulações computacionais para analisar as propriedades eletrônicas e estruturais desse material em nível de cristal e superfície. Os resultados foram comparados aos dados experimentais obtidos pelo método solvotérmico assistido por micro-ondas e discutidos em termos estrutura de bandas, densidade de estados e mapa de carga. Com relação ao parâmetro de rede e as coordenadas internas, a teoria utilizada apresentou bons resultados, corroborando com os dados obtidos experimentalmente. Valores de band gap teórico também se mostraram similares com os valores experimentais e indicaram transição direta em todos os modelos estudados.

Orientador: Roberto Rittner Neto / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T03:12:10Z (GMT). No. of bitstreams: 1 Doi_TelmaRie_D.pdf: 1964299 bytes, checksum: 3c38a112527a72cac6749c623cf285dd (MD5) Previous issue date: 2005 / Resumo: Estudou-se o equilíbrio conformacional de acetonas 1-monossubstituídas e 1,1-dissubstituídas por RMN, IV e cálculos teóricos. Os resultados que foram obtidos para as acetonas 1-halossubstituídas (cloro-, bromo-, e iodoacetona) mostraram a existência de dois rotâmeros mais estáveis, em todos os casos: cis e gauche, que foram previstos pelos cálculos teóricos e observados experimentalmente. O estudo conformacional realizado em cima das constantes de acoplamento JCH indicou que a população dos rotâmeros variava de acordo com a polaridade do solvente, sendo o rotâmero gauche predominante em solventes apolares e o cis predominante em solventes polares. Para as haloacetonas, as diferenças de energia entre os rotâmeros, calculadas e experimentais, mostraram uma boa correlação. O estudo do isomerismo rotacional das demais acetonas mostrou que o comportamento da constante de acoplamento JCH sofre variação com a conformação molecular, como havia sido observado para as haloacetonas, somente para a metoxiacetona e 1,1-dicloroacetona. Essa constante, portanto, só pôde ser empregada no estudo conformacional dessas duas acetonas. Para a metoxiacetona, os rotâmeros mais estáveis são o trans e o cis, sendo que a variação de JCH é devido aos sub-rotâmeros trans. Já para a 1,1-dicloroacetona, o rotâmero cis é predominante em solventes apolares e o gauche em solventes polares. Neste caso, também existe uma correlação entre os resultados calculados e experimentais. Para os outros compostos (hidroxiacetona, 1,1-dibromoacetona e N,N-dimetilaminoacetona), o uso de resultados de cálculos de efeito de solvente usando a teoria de Onsager auxiliaram no estudo do isomerismo rotacional / Abstract: The conformational equilibrium of 1-monosubstituted and 1,1-disubstituted acetones was studied by NMR, IR, and theoretical calculations. The existence of two most stable rotamers - cis and gauche - was shown to occur in all 1-halosubstituted acetones (chloro-, bromo-, and iodoacetone), as predicted by the theoretical calculations and observed experimentally. The JCH-based conformational study indicated that the rotamer population changed according to the solvent polarity: gauche predominates in less polar solvents, and cis predominates in more polar solvents. For the haloacetones, there was good correlation between the calculated and experimental rotamer energy differences. The study of the rotational isomerism of the other acetones showed that a similar behaviour of the JCH coupling constant only happened for methoxyacetone and 1,1-dichloroacetone. That constant, therefore, could only be used in the conformational study of those two acetones. Cis and trans rotamers are the most stable forms for methoxyacetone, and the JCH variation is due to the trans sub-rotamers. For 1,1-dichloroacetone, cis predominates in less polar solvents, and gauche in more polar solvents. In this case, there is also a good correlation between calculated and experimental results. For the other compounds (hydroxyacetone, 1,1-dibromoacetone, and N,N-dimethylaminoacetone), the use of solvent effect calculations based on Onsager's theory helped understand their rotational isomerism / Doutorado / Quimica Organica / Doutor em Quimica

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-01-19T14:07:51Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Vinicius Sousa Ferreira - 2014.pdf: 2847427 bytes, checksum: 6221d2131ccf2cfb6a29bc8074cb0e54 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-01-19T14:08:05Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Vinicius Sousa Ferreira - 2014.pdf: 2847427 bytes, checksum: 6221d2131ccf2cfb6a29bc8074cb0e54 (MD5) / Made available in DSpace on 2015-01-19T14:08:05Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Vinicius Sousa Ferreira - 2014.pdf: 2847427 bytes, checksum: 6221d2131ccf2cfb6a29bc8074cb0e54 (MD5) Previous issue date: 2014-07-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Solid dosage forms are the most widespread among pharmacists, due to its ease of handling and high adherence by patients, leading the growth of structural studies of drugs in this state. The technique of solid state NMR has gained increasingly space in analysis of drugs combined with other techniques, such as X- ray diffraction and infrared spectroscopy, besides having different types of computations as tools to aid structural characterization. The objective of this work is the characterization of the structure of the drug Lamivudine in its different forms via technique of nuclear magnetic resonance in the solid state with the aid of computer calculations as a confirmatory tool. The drug lamivudine, salicylate and biphthalate lamivudine salts prepared from lamivudine form II were characterized by X-ray diffraction (XRD) spectroscopy, mid-infrared (FITR), nuclear magnetic resonance solution (1H NMR and 13C {1 H}) and solid (CPMAS 13C NMR e15N), and the use of theoretical calculations of GIAO type by computer program GAUSSIAN and GIPAW by CASTEP program, for a relevant structure unambiguous assignment of NMR signals and confirmation of information of crystalline structure. The data obtained from experimental analysis were consistent with the structure of lamivudine and the results of theoretical calculations. The results were arranged in tables, and a statistical work was realized in order to correlate the experimental data with the theoretical, by analysis of the standard deviation (SD), mean deviation (MD), linear coefficient of determination (R2).The method GIPAW / CASTEP when purchased from GIAO / Gaussian was more significant studies to theoretical calculations in solid-state NMR, with values of R2, SD MD and 0.99 respectively, 2.5 and 3.6, while these same values for the GIAO were 0.92, 6.2 and 8.2. This difference in values is justified by the fact that the calculations GIPAW consider the pseudopotential plane-wave, not contemplated in GIAO calculations. It was found that the theoretical values of the chemical shifts 13C NMR, obtained by DFT / B3LYP theory, allowed for the drug excellent correlation with experimental values and permitted to associate a low computational cost at a good accuracy of the results obtained plus additional information not listed on experimental results, as in NMR spectra in the solid state. / As formas farmacêuticas sólidas são as mais difundidas no meio farmacêutico, devido a sua facilidade de manuseio e elevada adesão por parte dos pacientes, o que leva o crescimento de estudos estruturais de fármacos neste estado. A técnica de RMN no estado sólido ganha cada vez mais espaço em análises de fármacos aliadas a outras técnicas, como difração de raios-X e espectroscopia no infravermelho, além de contar com diversas modalidades de cálculos computacionais como ferramentas para auxílio de caracterização estrutural. O objetivo do presente trabalho é a caracterização da estrutura do fármaco lamivudina em suas diferentes formas via técnica de ressonância magnética nuclear no estado sólido com auxílio de cálculos computacionais como ferramenta confirmatória. O fármaco lamivudina e os sais salicilato e biftalato de lamivudina, preparados a partir da lamivudina forma II, foram caracterizados por difratometria de raios X(DRX), espectroscopia de infravermelho médio (FITR), ressonância magnética nuclear em solução (RMN de 1H e 13C{1H}) e de sólidos (RMN CPMAS de 13C e15N), além do uso de cálculos teóricos do tipo GIAO, pelo programa computacional GAUSSIAN e GIPAW pelo programa CASTEP, para uma atribuição inequívoca dos sinais de RMN e confirmação de informações pertinentes à estrutura cristalina. Os dados obtidos pelas análises experimentais foram coerentes com a estrutura da lamivudina e os resultados dos cálculos teóricos. Os resultados foram dispostos em tabelas, sendo realizado um trabalho estatístico de forma a correlacionar os dados experimentais com os teóricos, pela análise do desvio padrão (SD), desvio médio (MD), coeficiente de determinação linear (R2). A metodologia GIPAW/CASTEP quando comprada a GIAO/GAUSSIAN, se mostrou mais significativa para estudos de cálculos teóricos de RMN no estado sólido, com valores de R2, MD e SD de respectivamente 0,99, 2,5 e 3,6, enquanto esses mesmos valores para a GIAO foram de 0,92, 6,2 e 8,2. Essa diferença de valores é justificada pelo fato dos cálculos GIPAW considerarem os pseudopotenciais de onda plana, não contemplados nos cálculos GIAO. Verificou-se que os valores teóricos dos deslocamentos químicos de 13C de RMN, obtidos com a teoria DFT/B3LYP, possibilitaram para o fármaco em questão uma excelente correlação com os valores experimentais e permitiram associar um baixo custo computacional a uma boa precisão dos resultados obtidos além de complementar informações não elencadas em resultados experimentais, como ocorre em espectros de RMN no estado sólido.