INVESTIGADORES
MALDONADO alejandro Fabian
artículos
Título:
Relativistic effects on the shielding of the SnH2XY and PbH2XY (X, Y = F, Cl, Br and I) heavy-atom-containing molecules
Autor/es:
JUAN I. MELO; ALEJANDRO F. MALDONADO; GUSTAVO A. AUCAR
Revista:
THEORETICAL CHEMISTRY ACCOUNTS
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2011 vol. 129 p. 483 - 494
ISSN:
1432-881X
Resumen:
Full relativistic polarization propagator approach is one of the most reliables methods availables today for the calculation of NMR spectroscopic parameters on heavy-atom-containing molecules. When one wants to analyse the electronic origin of relativistic effects through two-components methods the LR-ESC method is efficient and have the advantage of the appearance of several mechanisms which do have different behavior depending on the molecular structure and the atoms analysed. In this article we present the study of the nuclear magnetic shieldings for the following systems: $SnXH_3$ $(X=H, F, Br, I)$, $SnXYH_2$ $(X,Y=F, Br, I)$ y $PbXH_3$ $(X=H, F, Br, I)$. Total LR-ESC calculations are confronted to benchmark calculations and then analysed in order to get the main trends and obtain the electronic origin of the shielding of all kind of atoms involved: the central, the hydrogen and the substituent atoms.The electronic origin of the heavy atom effects on vicinal heavy atoms, recently proposed, is analysed. It is shown that the passive third order Spin orbit mechanism do not explain the total pattern though is still the most important. There are two other mechanisms involved: the so called here PSO-OZ and the L-PSO-K. Both mechanisms do contain the PSO perturbative Hamiltonian. Quite a similar pattern though more intense is observed for the Lead atom when it is the central atom.