By using the building blocks Mo2(DAniF)3(O2CCH3) (DAniF = N,N'-di-panisylformamidinate) and [Mo2(cis-DAniF)2(NCCH3)4](BF4)2, a series of complexes with multiple dimolybdenum units, bridged by a variety of linkers and having various oxidation states, has been synthesized and studied by various physical and chemical methods. The isomeric neutral diamidate-bridged molecules, α– and β– (DAniF)3Mo2(ArN(O)CC(O)NAr)Mo2(DAniF)3 (Ar = p-anisyl), have been oxidized to give the PF6 salts of the four cations α1+, α2+, β1+, β2+; all four structures together with supporting evidence show that in α1+ and α2+ the unpaired electrons are localized while in β1+ and β2+ they are delocalized in the time scale of these experiments. It is also found that a hydroxide bridged complex having a [Mo2](µ-OH)2[Mo2] core undergoes a oxidative deprotomation, both in solution and in crystals, to a compound with a [Mo2](µ-O)2[Mo2] core. A probable key intermediate with one OH and one O bridge has also been characterized. One electron oxidation of the tetrabridged compounds [Mo2(cis-DAniF)2]2(µ-X)4, where X is a halogen atom (Cl, Br, I), produces a decrease of about 0.24 Å in the separation between the midpoints of the multiply bonded dimolybdenum units. DFT calculations suggest partial bond formation during the oxidation, which is consistent with NIR, EPR and electrochemical measurements. Additionally, a pair of isomeric cyclic triads containing three [Mo2(cis-DAniF)2]2+ units, bridged by six fluoride anions, have been synthesized and crystallographically characterized. The symmetry of the α isomer is C2v because the three [Mo2] units are oriented in two orthogonal directions while that of the other isomer is D3h because the three [Mo2] units are parallel. No direct interconversion between isomers has been detected by heating or irradiation of solutions but oxidation of the α isomer first generates an α+ species that changes to β+. Finally, reaction of [Mo2(cis-DAniF)2(NCCH3)4](BF4)2 and Bun 4NBH4 in ether gives [Mo2(cis-DAniF)2]2(µ-H)4 (14), a compound whose Mo4H4 core may be described as an elongated tetrahedron in which the four H atoms are along the four long edges and the Mo2 units along the short edges.

Made available in DSpace on 2014-12-17T15:41:57Z (GMT). No. of bitstreams: 1 JacksonSS_DISSERT.pdf: 3709927 bytes, checksum: 4cec63d3bb80372612d5fdea7750717f (MD5) Previous issue date: 2011-05-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This study aimed to identify and review of the conceptual differences presented by authors of books, focusing on the theme of electronic configuration. It shows the changing concepts of electronic configuration, its implications for the cognitive development of students and their relations with the contemporary world. We identified possible obstacles in books generated in the search for simplifications, situations of different concepts of energy in the electron configuration for sublevels. For this analysis was carried out in several books, and some other general chemistry and inorganic chemistry without distinguishing between level of education, whether secondary or higher. It was found that some books for school books corroborated with higher education, others do not. To check the consistency of what was discussed, it was a survey of 30 teachers, it was found divergent points of responses, particularly with respect to the energy sublevels and authorship of the diagram which facilitated the electron configuration. It was found that the total 22professores, ie, 73,33% answered correctly on the energy sublevel more calcium (Ca) and 80%, ie, 24 teachers responded incorrectly on the iron. As for the authorship of the diagram used to facilitate the electronic configuration, we obtained 93, 33% of teachers indicated that they followed a diagram, and this was called "Diagram of Linus Pauling," teacher 01, 3,33%, indicated that the diagram was authored by Madelung and 01, 3,33%, did not respond to question. Was observed that it is necessary a more detailed assessment of ancient writings, as the search for simplifications and generalizations, not so plausible, lead to errors and consequences negative for understanding the properties of many substances. It was found that quantum mechanics combined with spectroscopic data should be part of a more thorough analysis, especially when it extends situations atoms monoelectronicpolieletr?nicos to describe atoms, because factors such as effective nuclear charge and shielding factor must be taken into consideration, because interactions there is inside an atom, described by a set ofquantum numbers, sometimes not taken into account / Este trabalho teve como objetivo a identifica??o e coment?rio das diferen?as conceituais apresentadas por autores de livros, enfocando o tema configura??o eletr?nica. Essa an?lise mostra as mudan?as de conceitos sobre configura??o eletr?nica, suas implica??es no desenvolvimento cognitivo de alunos e as suas rela??es com o mundo contempor?neo. Identificou-se em livros poss?veis entraves gerados na busca de simplifica??es, situa??es de diferentes conceitos de energia na configura??o eletr?nica por subn?veis. Para tanto foi realizada uma an?lise em v?rios livros, sendo alguns de qu?mica geral e outros de qu?mica inorg?nica sem distin??o entre n?vel de ensino, se m?dio ou superior. Verificou-se que alguns livros de ensino m?dio corroboravam com livros de ensino superior, outros n?o. Para verificar a consist?ncia do que se estava analisado, fez-se uma pesquisa com 30 professores, em que foi encontrado pontos divergentes de respostas, com rela??o principalmente ? energia de subn?veis e autoria do diagrama que facilitava a configura??o eletr?nica. Constatou-se que do total, 22 professores, ou seja, 73,33% responderam corretamente sobre o subn?vel mais energ?tico do c?lcio (Ca) e 80%, ou seja, 24 professores responderam incorretamente sobre o ferro. J? quanto a autoria do diagrama usado para facilitar a configura??o eletr?nica, obteve-se93,33% de professores que indicaram que seguiam um diagrama, e este era denominado de diagrama de Linus Pauling , 01 professor, 3,33%, indicou que o diagrama era de autoria de Madelung e 01, 3,33%, n?o respondeu a pergunta.Foi observado que ? necess?rio uma avalia??o mais minuciosa de escritos antigos, pois a busca de simplifica??es e generaliza??es, n?o t?o plaus?veis, levam a erros e consequ?ncias negativas para a compreens?o das propriedades de muitas subst?ncias. Verificou-se que a mec?nica qu?ntica aliada a dados espectrosc?picos deve fazer parte de uma an?lise mais minuciosa, principalmente quando se estende situa??es de ?tomos monoeletr?nicos para descrever ?tomos polieletr?nicos, pois fatores como carga nuclear efetiva e fator de blindagem devem ser levados em considera??o, devido a intera??es que h? internamente num ?tomo, descrito por um conjunto de n?meros qu?nticos, ?s vezes n?o levados em considera??o

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