Ligações químicas em complexos de metais de transição: estrutura e densidade eletrônica em cristais

Abstract

The relevant properties of coordination compounds are a direct consequence of the electron distribution in these compounds, hence a better understanding of chemical bonds and interactions are crucial for the development of compounds with desired properties. In order to evaluate the influence of transition-metals nature in interactions and crystal structure, an isostructural series of coordination compounds presenting short hydrogen bond has been analyzed through single-crystal X-ray diffraction. The structures were evaluated through both a spherical (Independent Atom Model) and aspherical atom description (Multipole Model and Hirshfeld Atom Refinement), evaluating chemical bonds and interactions through geometric parameters, Hirshfeld surface analysis and topological analysis. It could be concluded that all chemical bonds involving transition metal and oxygen atoms are better defined as intermediate between ionic and covalent. It was also concluded that the covalence degree of the short hydrogen bonds are dependent on the nature of the metal present in the compound, in this manner, the Mn compound presents the most covalent short hydrogen bond and the Ni compound has the least covalent short hydrogen bond. A comparison between partitioning methods was also conducted, as means to find a correlation between them. To do so, literature data was used and the correlation was later applied to the compounds under study.