Estudo estrutural de complexos de cobre (II) como modelos de sítios metálicos de enzimas com atividade oxidativa

• Ano de defesa: 2009
• Autor(a) principal: SOUSA JÚNIOR, Joel Padilha de
• Orientador(a): SABINO, José Ricardo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Mestrado em Física
• Departamento: Ciências Exatas e da Terra
• País: BR
• Palavras-chave em Português: Difração de raio X; molécula orgânica, estrutura cristalina
• Palavras-chave em Inglês: X-ray diffraction; organic molecule, crystal structure
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA::FISICA ATOMICA E MOLECULAR
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tde/819

We present the structural study, by x-rays diffraction, of two forms on the crystalline and molecular structures of the metal-organic single-crystal compounds Dicloro[N- benzoyl-N´-(4-methylphenyl)-N´´-(2-pyridinyl)-guanidine)]copper(II). Such compound is known for the phenol oxidative catalictic bioactivity. The compound is a copper(II)-guanidine de- rivative complex. The main motivation of the present work is the polimorphism observed on such complex when the crystallization conditions are changed. The structures were sol- ved using the Direct Methods method and the structural parameters were refined with full matrix least-squares method. The copper(II) complex C19H22Cl2CuN4O crystallizes in the triclinic system in the P¯1 space group, with a single molecule in the assymetric unit and unit cell parameters: a = 8.616 (3) °A, b = 9.288 (3) °A, c = 13.623 (2) °A, α = 106.96 (2)o, β = 96.02 (3)o, γ = 100.60 (2)o, with volume 1010.3 (5) °A3 and calculated density of 1.528 Mgm−3. The same compound also crystallizes in the monoclinic system in the P21/n space group and unit cell parameters: a = 7.937 (2) °A, b = 18.727 (2) °A, c = 13.993 (2) °A, β = 102.03 (2)o, with volume 2034.2 (6) °A3 and calculated density 1.518 Mgm−3. The two isomeric molecules showed different conformations from one crystal packing to the other, due to the different intermolecular interactions. Given the different crystal packing and intermolecular interactions, we performed electronic structure calculations using the Density Functional Theory in order to derive the energetic differences, including calculations of dimers linked by hydrogen bonds, for evaluating the crystal packing influence on the complex stability in their crystal structures.