Graft copolymers with a dendritic (arborescent) architecture and unimolecular micelle properties have been synthesized and examined for their solution properties as well as their ability to serve as templates for the preparation of metallic nanoparticles. The research focused on two types of arborescent copolymers, namely core-shell (CS) and core-shell-corona (CSC) architectures. Copolymer amphipolarity was provided by a hydrophobic polystyrene (PS) component and a polar poly(2-vinylpyridine), P2VP, phase. The CS copolymers were obtained by grafting P2VP onto linear or branched PS substrates to yield PS-g-P2VP unimolecular micelles. These copolymers exhibited solubility with limited aggregation in aqueous environments after protonation with HCl. Coordination of the coronal P2VP phase with HAuCl4 was achieved, and the resulting polymer-stabilized metallic nanoparticles had a spherical morphology. The tri-layered copolymers were synthesized in similar fashion, by grafting PS-b-P2VP block copolymers onto linear or branched PS substrates to afford a CSC morphology with a PS core, a P2VP inner shell, and a PS corona. While the grafting reaction proceeded with lower than expected grafting yields as compared to grafting reactions of homopolymer side-chains, significant P2VP content and molecular weight increases were achieved. It was determined that aggregation of the block copolymer side-chains hindered the coupling reaction of the reactive centers with the substrate. After purification of the PS-g-(P2VP-b-PS) arborescent copolymers, in part by developing a cloud-point centrifugation purification technique, the spherical copolymers were successfully loaded with various metallic compounds. The uptake of compounds such as HAuCl4 by the P2VP phase of the copolymers induced intramolecular phase segregation for copolymers of generations (G) 2 and above. Phase segregation produced some unique and intricate morphologies different from the ones observed previously for other unimolecular metal scaffolds. Intramolecular toroidal, nodular, and cylindrical morphologies were observed for the G2, G3, and G4 arborescent copolymers, respectively. Templates of generations 0 and 1 displayed a spherical morphology similar to their PS-b-P2VP intermolecular micelle analogues when loaded with metals. Phase segregation is believed to be mediated mainly by the characteristics of the PS core, the length of the P2VP segments having less influence on the morphologies obtained. Reduction of the metallic salts was performed using various agents and protocols. Stronger reducing agents yielded smaller and more narrowly distributed gold nanoparticles, while other reduction methods also removing the polymer scaffold resulted in larger nanoparticles.

Graft copolymers with a dendritic (arborescent) architecture and unimolecular micelle properties have been synthesized and examined for their solution properties as well as their ability to serve as templates for the preparation of metallic nanoparticles. The research focused on two types of arborescent copolymers, namely core-shell (CS) and core-shell-corona (CSC) architectures. Copolymer amphipolarity was provided by a hydrophobic polystyrene (PS) component and a polar poly(2-vinylpyridine), P2VP, phase. The CS copolymers were obtained by grafting P2VP onto linear or branched PS substrates to yield PS-g-P2VP unimolecular micelles. These copolymers exhibited solubility with limited aggregation in aqueous environments after protonation with HCl. Coordination of the coronal P2VP phase with HAuCl4 was achieved, and the resulting polymer-stabilized metallic nanoparticles had a spherical morphology. The tri-layered copolymers were synthesized in similar fashion, by grafting PS-b-P2VP block copolymers onto linear or branched PS substrates to afford a CSC morphology with a PS core, a P2VP inner shell, and a PS corona. While the grafting reaction proceeded with lower than expected grafting yields as compared to grafting reactions of homopolymer side-chains, significant P2VP content and molecular weight increases were achieved. It was determined that aggregation of the block copolymer side-chains hindered the coupling reaction of the reactive centers with the substrate. After purification of the PS-g-(P2VP-b-PS) arborescent copolymers, in part by developing a cloud-point centrifugation purification technique, the spherical copolymers were successfully loaded with various metallic compounds. The uptake of compounds such as HAuCl4 by the P2VP phase of the copolymers induced intramolecular phase segregation for copolymers of generations (G) 2 and above. Phase segregation produced some unique and intricate morphologies different from the ones observed previously for other unimolecular metal scaffolds. Intramolecular toroidal, nodular, and cylindrical morphologies were observed for the G2, G3, and G4 arborescent copolymers, respectively. Templates of generations 0 and 1 displayed a spherical morphology similar to their PS-b-P2VP intermolecular micelle analogues when loaded with metals. Phase segregation is believed to be mediated mainly by the characteristics of the PS core, the length of the P2VP segments having less influence on the morphologies obtained. Reduction of the metallic salts was performed using various agents and protocols. Stronger reducing agents yielded smaller and more narrowly distributed gold nanoparticles, while other reduction methods also removing the polymer scaffold resulted in larger nanoparticles.

This research explores the links between the structure and dissociation energetics of ionized non-covalent complexes. In chapter 3, a large series of similar non-covalent complexes were probed using electrospray tandem mass spectrometry (ESI-MS/MS) and RRKM modelling in order to identify any trends in the dissociation energetics based on charge state, overall size of the complex, or size of the substrate. Ion mobility spectrometry (IMS) in conjunction with molecular mechanics/molecular dynamics (MM/MD) was used to study the conformations of these non-covalent complexes in order to determine if the same trends identified in the energetics could be corroborated independently based on structure. The system of study consisted of varying lengths of the synthetic polymer, polymethylmethacrylate (PMMA) complexed with singly or doubly protonated diaminoalkanes (DAA) of varying length. The critical energies of dissociation (E0) increased as the length of the polymer increased and was not significantly affected by the length of the singly protonated DAA substrates. The E0 of dissociation of doubly protonated complexes was strongly influenced by the length of the DAA; longer DAA substrates had greater separation of charge which decreased coulombic repulsion within the complex resulting in higher E0 values. MM/MD low energy structures of all complexes were validated with experimental IMS measurements and showed that the arrangement between the polymer and DAA were similar for different singly protonated DAAs. When doubly protonated, the length of DAA was the most important factor in determining the overall structure of the complex. In chapter 4, a direct link is shown between the observed E0 dissociation energies and the molecular conformations for eight different peptide–saccharide complexes containing either a tri-saccharide (d-(+)-raffinose and d-panose) or tetra-saccharide (stachyose and maltotetraose) with a small peptide (FLEEL and FLEEV). The E0 values were highly related to the overall conformation adopted by the non-covalent complex in the gas phase. Complexes containing peptide FLEE(L/V) with the tri-saccharide raffinose or panose had similar E0 of dissociation (∼0.64 eV) and similar conformations based on MM/MD simulations and IMS drift times. Conversely, for complexes containing a FLEE(L/V) peptide with one of the isomeric tetra-saccharides; stachyose had a E0 ∼0.08 eV greater than maltotetraose. This difference of intermolecular interaction was also reflected by the IMS drift times; maltotetraose in complex with FLEEV or FLEEL had a 5.9% and 2.3% faster IMS drift time than stachyose respectively. This indicated that the molecular arrangement between maltotetraose and the peptides was more compact than the stachyose-peptide complexes. In chapter 5, RRKM modelling of breakdown diagrams is not possible when the reactant ion signal is overlapped by other isobaric species. Trimeric, non-covalent complexes that contained two PMMA molecules and a doubly protonated DAA, [(PMMAa)(DAA+2H)(PMMAb)]+2, have m/z signals that contain multiple different complexes having the same total number of polymer repeat units but differ in the length of the each polymer. In this situation, the applicability of using the simple kinetic method to gain insight into relative binding energies was explored. The major factors which determined the suitability of the kinetic method for this system were identified as the structural arrangement of the reactant ion complex, possible reverse activation barriers, and the evaluations of Δ(ΔS‡). MM/MD simulations coupled with IMS suggests that within the reactant ion, the DAA is almost equally shared between two PMMA oligomers and that the two PMMA oligomers interact predominately with the DAA, and not with each other. MS/MS of the trimeric reactant complexes proceeds by neutral loss of one polymer and is suggested to proceed with little or no reverse activation barrier based on the low coulombic repulsion factors. The IMS drift times of [(PMMAa)(DAA+2H)]+2 complexes that were generated directly by ESI-MS or by dissociation of a trimeric, [(PMMAa)(DAA+2H)(PMMAb)]+2 complex were found to be identical. This provides some evidence that Δ(ΔS‡) ≈ Δ(ΔS) and using a statistical mechanics approach, Δ(ΔS) ≈ 0. The effective temperature (Teff) variable in the kinetic method expression was found to decrease as a function of the size of the trimeric complex, suggesting that the population distribution of the dissociating ensemble of complexes narrows as size increases. Overall, when RRKM fitting is not possible, the simple kinetic method could provide relative energetic ranking of competing dissociations reactions however the Teff term contributed to the greatest uncertainty in obtaining absolute quantities. Fitting MS/MS breakdown diagrams of non-covalent complexes with multiple dissociation channels is difficult due to the number of total fitting variables. Building from the simple kinetic method, chapter 6 shows that the relationship between the natural logarithm of competing fragment ions and reciprocal collision energy yields a branching relationship that allows for the sign of Δ(ΔS‡) and Δ(E0) between the channels to be obtained. Furthermore, the relationships between the fitting variables of RRKM modelling are empirically related to the theoretical branching relationship characteristics. This allowed for the fitting variables of all dissociation channels to be expressed as a function of a single channel so that the theoretical branching relationship matches the experimental branching relationship. Using this method, RRKM fitting of a MS/MS breakdown diagram for APCI ionized anthracene determined the E0 and ∆S‡ was 4.69 ± 0.29 eV and -3 ± 17 J K-1; 4.21 ±0.29 eV and -19 ±15 J K-1; and 4.81 ± 0.29 eV and 36 ±22 J K-1 for hydrogen loss, acetylene loss and diacetylene loss respectively. With one exception, these values are within experimental error of the iPEPICO derived energetic values. In chapter 7, MS/MS of ammoniated triacylglycerides at multiple collision energies and computational analysis are used to explain the cause of uneven dissociation rates of the FAs from different positions on the glycerol backbone. The loss of sn-1 and sn-3 FAs are found to have lower activation energies than the loss of the sn-2 position FA, however the loss of the FA from the sn-2 position is more entropically favourable. Theoretical MS/MS breakdown curves were fit to experimental values using RRKM theory to estimate the E0 of dissociation of FAs from the three glycerol positions. The E0 values for cleavage from the sn-1 and sn-3 positions were found to be approximately 1.52 eV, while that for the sn-2 position was highly dependent on the identity of the FA at that position. Computational structures and energy analysis suggest that an important step in the dissociation of [TAG+NH4]+ is the loss of ammonia. In a model system, glyceryl tributyrate, the loss of NH3 produced two distinct [TAG+H]+ product structures sitting 148 kJ and 160 kJ in energy above the ammoniated structure. The [TAG+H]+ structure that leads to the loss of the sn-1(3) is 12 kJ lower than the [TAG+H]+ structure that leads to the loss of the sn-2 FA. From this, the loss of a neutral FA that follows sits only an additional 35–48 kJ above the [TAG+H]+ structures. In Chapter 8, singly deprotonated β-cyclodextrin monomers, [(β-CD-H+]-1, and doubly deprotonated dimers, [(β-CD)2-2H+]-2, are both present following ESI-MS and have the same monoisotopic m/z. Similar to chapter 5, this makes it difficult to generate an MS/MS breakdown diagrams that can be modelled with RRKM theory. IMS was used to mobility separate [(β-CD-H+]-1 and [(β-CD)2-2H+]-2 and was followed by MS/MS of the [(β-CycD)2-2H+]-2 ion. A second problem when generating a MS/MS breakdown diagram of non-covalent complexes that contain identical components is that the fragment ions could have an identical monoisotopic m/z as the reactant ion. MS/MS of [(β-CycD)2-2H+]-2 results in two [(β-CD-H+]-1 fragments. To overcome this, breakdown diagrams were then generated by monitoring the changes in the isotopic profile. The RRKM derived E0 for dissociation of [(β-CycD)2-H+]-1 and [(β-CycD)2-2H+]-2 were 1.85 ± 0.11eV and 1.79 ± 0.09eV, respectively, corresponding to a slight decrease in complex stability due to increased charge-charge repulsion in the dianion.

Yes / The synthesis of cyclic amphiphilic graft copolymers with a hydrophobic polycarbonate backbone and hydrophilic poly(N-acryloylmorpholine) (PNAM) side arms via a combination of ring-opening polymerization (ROP), cyclization via copper-catalyzed azide–alkyne cycloaddition (CuAAC), and reversible addition–fragmentation chain transfer (RAFT) polymerization is reported. The ability of these cyclic graft copolymers to form unimolecular micelles in water is explored using a combination of light scattering, small-angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryoTEM) analyses, where particle size was found to increase with increasing PNAM arm length. Further analysis revealed differences in the solution conformations, loading capabilities, and morphologies of the cyclic graft copolymers in comparison to equivalent linear graft copolymer unimolecular micelle analogues. Furthermore, the cyclic and linear graft copolymers were found to exhibit significantly different cloud point temperatures. This study highlights how subtle changes in polymer architecture (linear graft copolymer versus cyclic graft copolymer) can dramatically influence a polymer’s nanostructure and its properties. / Royal Society (Great Britain), Engineering and Physical Sciences Research Council (EPSRC), European Research Council (ERC)

Die Oberflächen-stoßinduzierte Fragmentierung von reinen und gemischten Antimonclustern wurde im Bereich hyperthermischer Kollisionsenergien untersucht. In diesem Energiebereich sind die Prozesse des Ladungstransfers, des Energietransfers sowie der Fragmentierung der Cluster besonders wichtig. Die Cluster wurden in einer gepulsten Bogenentladungsquelle erzeugt und nach Massenselektion in einem Flugzeit-Massenspektrometer mit sechs verschiedenen Oberflächen (Diamant, Siliziumdioxid, Antimon(III)oxid, Gold, Graphit und einer fluorierten organischen Monolagenoberfläche (C10-F-SAM)) unter Ultrahochvakuumbedingungen zur Wechselwirkung gebracht. Die daraus hervorgehenden ionischen Produkte wurden in einem zweiten Flugzeit-Massenspektrometer analysiert. Der Ladungstransfer zwischen Projektilion und Oberfläche zeigte deutliche Unterschiede in Abhängigkeit von der Oberfläche. Dieser Effekt wurde anhand der Gesamtfragmentionenausbeute studiert und kann gut durch die unterschiedlichen Austrittsarbeiten beschrieben werden. Die Effektivität der Oberflächen hinsichtlich des Transfers von kinetischer in innere Energie der auftreffenden Cluster ließ sich aus den Massenspektren der Fragmentionen bestimmen. Diese konnten aufgrund der bekannten Bindungsenergien der Antimon-Cluster mittels der Thermometermolekülmethode ausgewertet werden. Es wurde eine für alle Clustergrößen charakteristische Korrelation zwischen Energietransfereffektivität und Oberfläche festgestellt. Von allen untersuchten Oberflächen zeigt die F-SAM-Oberfläche den geringsten Energieübertrag. Der höchste Energieübertrag wird bei der Streuung an der Diamantoberfläche gemessen. Die Energieübertragseffektivität der anderen Oberflächen reiht sich zwischen diesen beiden Extremen ein. Diese Korrelation konnte sowohl mit makroskopischen (Härte) als auch mit mikroskopischen (Bindungsenergie, interatomare Abstände und Debye-Temperatur) Eigenschaften der zugehörigen Festkörper erklärt werden. / Surface-induced fragmentation of pure and mixed antimony clusters was investigated within the hyperthermal collision energy range. Charge transfer, energy transfer and fragmentation of the clusters are important processes in this range. Clusters were produced in a pulsed arc-discharge cluster ion source (PACIS) and mass-selected in a time-of-flight mass spectrometer. In a next step, the clusters were brought into interaction with six different surfaces (diamond, silicon dioxide, antimony(III)oxide, gold, graphite and a self-assembled organic mono-layer surface (C10-F-SAM)) under ultra-high vacuum conditions. The emerging product ions were analysed in a second time-of-flight mass spectrometer. A notable difference between the six surfaces was found with respect to the charge transfer between projectile ion and surface. This effect was analysed in considering the total fragment ion yield and can be attributed to the different work functions of these surfaces. The transfer from translational energy into vibrational modes of the impinging clusters has been determined from the mass spectra of the fragment ions as a function of the surface. The known binding energies of the antimony clusters allow the use of the thermometer molecule model to evaluate the fragment ion distribution. A correlation between the energy transfer efficiency and the type of surface was found which is valid for all cluster sizes. From all the surfaces, which have been investigated, the F-SAM surface shows the lowest and the diamond surface shows the highest energy transfer efficiency. The efficiency of the other surfaces falls in-between these two extremes. The correlation between the energy transfer efficiency of a surface and the kind of surface can be satisfactorily explained in terms of either macroscopic (hardness) or microscopic (binding energy, interatomic distances and Debye-temperature) properties of the solids.

No description available.

Thermodynamic stabilities of eighteen cyclic C5H6 isomers were explored computationally both on singlet and triplet state potential energy surfaces (PES). All isomers have singlet ground states except for bicyclo[2.1.0]pent-5-ylidene (B5) having no stable geometry on the singlet C5H6 PES. Cyclopenta-1,3-diene (M1) is the most stable cyclic C5H6 isomer while cyclopent-1,4-diylidene is the least stable one among all. Cyclopenta-1,2-diene (M2) and cyclopentyne (M3) have biradical characters of 46.9 and 21.5%, respectively. Seven unimolecular isomerization reactions occurring among several of these molecules were investigated by DFT and ab initio methods. The conversion of bicyclo[2.1.0]pent-2-ene (B1) and tricyclo[2.1.0.02,5]-pentane (T1) into 1,3-cyclopentadiene (M1) are shown to be concerted processes whose reaction paths pass through TSs with a high degree of biradical character. The reaction enthalpies (DH0) are predicted to be -47.7 kcal/mol for B1 and -63.8 kcal/mol for T1 at UB3LYP/6-31G(d) level. The activation enthalpy (DH0&sup1 / ) for the ring opening of B1 was calculated by the CR-CCSD(T) method to be 25.2 kcal/mol, in good agreement with experiment. Furthermore, the DH0&sup1 / for the ring opening of T1 was obtained by the CR-CCSD(T) method to be 48.2 kcal/mol. The self-conversion of M1 via 1,5-hydrogen shift is a facile and concerted reaction with aromatic TS. The DH0&sup1 / estimations of B3LYP and CC methods are 25.24 and 28.78 kcal/mol, respectively. For 1,2-hydrogen shift reactions of cyclopent-3-enylidene (M4) and cyclopenten-2-ylidene (M5), the single point CC calculations predicted the DH0&sup1 / values of 3.13 and 10.12 kcal/mol, as well as, the DH0 values of -71.28 and -64.05 kcal/mol, respectively. The reason of M5 being more stable than M4 is due to the conjugation of the carbene carbon and the double bond in M5. The reaction path of cyclobutylidene methylene to cyclopentyne rearrangement is found to be rather shallow. The DH0&sup1 / and DH0 values predicted by the RCCSD(T) method to be 3.65 and -5.72 kcal/mol, respectively. Finally, triplet state isomerization of bicyclo[2.1.0]pent-5-ylidene to cyclopenta-1,2-diene, as well as, its parent reaction, cyclopropylidene to 1,2-propadiene were investigated at several levels of theory including DFT, CASSCF and CC methods. The UCCSD(T) method estimated a moderate barrier whose value is 8.12 kcal/mol for the isomerization of 3B5 with the reaction enthalpy of -44.63 kcal/mol.

This work reports a novel biocompatible and biodegradable arborescent amphiphilic polypept(o)ides-based polymer poly(γ-benzyl L-glutamate)-co-poly(γ-tert-butyl L-glutamate)-g-polysarcosine (P(BG-co-Glu(OtBu))-g-PSar) as a smart dual-responsive targeting drug vehicle. The synthesis pathway in this work highlighted the grafting reaction improvement of the polypeptides core and using polysarcosine (PSar) corona as a coating agent. The responsiveness of the polymer is caused by the pH sensitivity of the polypeptides and the reducible linker introduced between the core and corona. While adding the tripeptides arginine, glycine, and aspartate (RGD) as a ligand on the unimolecular micelles’ surface increases the targeting ability of the polymer. During the building of the arborescent, the coupling sites were controlled by using γ-tert-butyl L-glutamate (Glu(OtBu)-NCA) as a second monomer besides γ-benzyl L-glutamate (BG-NCA) since the deprotection conditions are different for Bz and tBu groups. Knowing the coupling sites provides accuracy in calculating the molecular weight (MW) of graft polymers since it facilitates the determination of the grafting yield (Gy). The arborescent unimolecular micelles were formulated by coating the hydrophobic core with PSar hydrophilic corona. The distribution of the coupling sites on the substrates in the last generation yielded end-grafted and randomly-grafted unimolecular micelles. A comparison between those micelles by DLS, TEM, and AFM revealed that the end-grafted micelles showed more uniformity in terms of morphology and size distribution. Also, the surface modification achieved via RGD addition increased the shape uniformity and contributed to avoiding the particles’ aggregation. The sizes and shapes of end-grafted unimolecular micelles match the drug delivery systems (DDSs) requirements. Doxorubicin (DOX) was encapsulated physically into the unimolecular micelles to study the drug loading capacity (DLC) and drug loading efficiency (DLE). The maximum DLC and DLE were 14% and 28% w/w, respectively. The drug release profiles were investigated in healthy- and cancer-mimicking media. The results showed that in cancer-mimicking microenvironment (low pH and high glutathione (GSH) content), the drug diffused out the micelles faster. In addition, a slower drug release was noticed for RGD decorated unimolecular micelles. Finally, the biocompatibility, cytotoxicity, and cellular uptake of the unimolecular micelles were studied. The obtained results were promising as the arborescent unimolecular micelles showed excellent biocompatibility; meanwhile, the DOX-loaded unimolecular micelles have good cytotoxicity compared to free DOX. RGD targeting ligand contributes to increasing the cellular uptake and supports the sustained release.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Cálculos usando métodos de estrutura eletrônica (Hartree-Fock, Mõller-Plesset de segunda ordem e DFT, B3LYP) foram efetuados pelo programa Gaussian98 em microcomputadores e estações de trabalho, com o objetivo de elucidar os canais de decomposição unimolecular de éter dietílico em fase gasosa e foram comparados com valores obtidos através de aproximações baseadas na mecânica estatística pela metodologia de Benson. O éter dietílico vem sendo usado como um aditivo para o óleo diesel e combustível alternativo e o conhecimento de suas vias vias de decomposição é fundamental nestas investigações. Dezesseis modos primários, do qual, quatro ocorrem através de cisão de ligações simples C-O, C-C,C(1)-H e C(2)-H e doze ocorrendo através de estados de transição cíclicos, os quais eliminam produtos como hidrogênio etano, acetaldeído, etano, álcool etílico, metil etil éter, metano, alguns carbenos e também di-radicais, foram considerados para a determinação das barreiras de ativação, entalpias de reação, entropias de reação e energia livre de Gibbs de reação. Vias primárias ocorrendo através de cisão de ligação, não reproduziram os valores experimentais para as barreiras de ativação, mas reproduziram de modo significante, valores da entalpia da reação. Eliminação de eteno e álcool etílico, ocorrendo através de um estado de transição de quatro centros, apresentou a barreira de ativação mais baixa. Acetaldeído e eliminação de etano, ocorrendo através de quatro centros, apresentou barreira significativamente alta, mas por outro lado, a menor entalpia, ligeiramente exotérmica por -0,8 kcal.mol-1. Eliminações 1,2 de metano e carbeno ocorrendo através de três centros, junto com a eliminação 1, 1 de hidrogênio e carbeno por três centros, eliminação 2,2 hidrogênio e carbeno por três centros e eliminação 1,4 de hidrogênio, acetaldeído e eteno por seis centros, apresentaram barreiras de ativação relativamente próximas mostrando que elas são competitivas entre si. Os valores computados dos canais que ocorrem por estados de transição cíclicos foram comparados com os resultados experimentais disponíveis e discutida a validade desta abordagem computacional para o estudo de reações unimoleculares de multi-canais. Determinação de parâmetros termoquímicos, como calor de formação para espécies radicalares dos canais de decomposição primário e alguns radicais alcóxidos, junto com a estimativa de afinidade eletrônica e protônica (com a abordagem ab initio Gaussian 2 a qual estima energias eletrônicas muito precisas) foram efetuados e seus resultados foram comparados com os valores experimentais disponíveis e valores obtidos através de energias de ligação e da regra de aditividade de Benson. / Calculations using methods of electronic structure(Hartree-Fock, second order Moller-Plesset and DFT: B3LYP) had been effected through the Gaussian98 program in microcomputers and workstations, with the objective to elucidate the unimolecular decomposition channels of diethyl ether in gaseous phase. These results also had been compared to those obtained by the methodology based in statistical mechanics through Benson\'s approach. Sixteen primary ways, which, four occur through the break of simple bonds C-O, C-C,C(1)-H, C(2)-H, and twelve occur through cyclical transistion states, which eliminate products as hydrogen, ethene, acetaldehyde, ethane, ethyl alcohol, methyl ethyl ether, methane, some carbenes and also diradicals. These products had been considered to the determination of the activation barriers, enthalpies of reaction, entropies of reaction and free energy of Gibbs of reaction. Primary ways occurring through the break of bonds, had not reproduced experimental values for the activation barriers, however they had reproduced in a significant way, values of the enthalpy of the reaction. Elimination of ethene and ethyl alcohol, occurring by a transition state of four centers, presented the lowest activation barrier. Acetaldehyde and ethane elimination occurring through four centers, presented a high significantly barrier, but on the other hand it presented the smallest enthalpy, lightly exothermic above -0,8 kcal.mol-1. Eliminations 1,2 of methane and carbene occurring through three centers, together with the elimination 1,1 of hydrogen and carbene through three centers, elimination 2,2 of hydrogen and carbene through three centers and elimination 1,4 of hydrogen, acetaldehyde and ethene through six centers, had presented relatively next activation barriers, showing that they are competitive among themselves. The computed values of the channels that occur through cyclical transition states had been compared with the available experimental results and the trustworthiness of this computational boarding for the study of unimolecular reactions in multi-channel had been dicussed. Determination of thermochemical parameters, as heat of formation for radicalar species of the primary channel of decomposition and some alcoxyde radicais, together with the estimative of the electronic and protonic affinities,( with the ab initio Gaussian 2 boarding which estimate very precise eletronic energies ) and their results had been compared with the available experimental values and with values gotten through energies of bond and Benson\'s additivity rule.