Eletronic charge density at high resolution x-rays diffraction and topological anlysis using the multipole model in single crystals compounds of biological interest / Densidade eletrônica por difração de raios-x à alta resolução e análise topológica com modelo multipolar em compostos monocristalinos de interesse biológico

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The bonding properties of the transition metal complex Cu(I1)-L-alanyl-L-valine and the Taurine compound have been determined by high resolution x-ray diffraction. The charge density analysis is performed using the Hansen-Coppens multipole model for both, the topological study of the electron density p(f) and the orbital populations analysis of the transition metal. Short wavelength synchrotron radiation (0.394 angstrom) and vaporized helium temperature were used in the x-ray diffraction data collection of the metal complex. For the dx2-y2 orbital, the half population obtained is shown by the 4-fold depletion region in the static deformation and negative Laplacian maps. Values of the charge density and its curvature in the critica1 points located at the Cu-N and Cu-O bonds show the non-ionic character of these interactions. We have derived an algorithm to perform preferencial orientation search for the first row transition metal d-orbitals in non-symmetric sites. Atomic charge integration was carried out applying topological atoms partitioning (basins). The charge density of Taurine has been studied with data collected with a KappaCCD diffractometer using Kalfa-Mo radiation at vaporized N2 temperature and neutron diffraction data obtained from the literature. Topological properties of rô(VET.r) were calculated from the fitted model. Atomic charges given by the monopole parameters have been compared with those obtained by integration of the atomic basins and theoretical molecular calculations.

ASSUNTO(S)

biological interest complexos de cobres densidade de carga x-ray diffraction high resolution interesse biológico charge density difração de raios x copper complexes alta resolução

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