Sparkle Model for AM1 Calculation of Lanthanide Complexes: Improved Parameters for Europium
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- 作者：Gerd B. Rocha ; Ricardo O. Freire ; Nivan B. da Costa ; Jr. ; Gilberto F. de Sá ; and Alfredo M. Simas
- 刊名：Inorganic Chemistry
- 出版年：2004
- 出版时间：April 5, 2004
- 年：2004
- 卷：43
- 期：7
- 页码：2346 - 2354
- 全文大小：126K
- 年卷期：v.43,no.7(April 5, 2004)
- ISSN：1520-510X
文摘
In the present work, we sought to improve our sparkle model for the calculation of lanthanide complexes, SMLC,in various ways: (i) inclusion of the europium atomic mass, (ii) reparametrization of the model within AM1 from anew response function including all distances of the coordination polyhedron for tris(acetylacetonate)(1,10-phenanthroline) europium(III), (iii) implementation of the model in the software package MOPAC93r2, and (iv) inclusionof spherical Gaussian functions in the expression which computes the core-core repulsion energy. The parametrizationresults indicate that SMLC II is superior to the previous version of the model because Gaussian functions provedessential if one requires a better description of the geometries of the complexes. In order to validate ourparametrization, we carried out calculations on 96 europium(III) complexes, selected from Cambridge StructuralDatabase 2003, and compared our predicted ground state geometries with the experimental ones. Our resultsshow that this new parametrization of the SMLC model, with the inclusion of spherical Gaussian functions in thecore-core repulsion energy, is better capable of predicting the Eu-ligand distances than the previous version. Theunsigned mean error for all interatomic distances Eu-L, in all 96 complexes, which, for the original SMLC is0.3564 Å, is lowered to 0.1993 Å when the model was parametrized with the inclusion of two Gaussian functions.Our results also indicate that this model is more applicable to europium complexes with 
beta2.gif" BORDER=0 ALIGN="middle">-diketone ligands. Assuch, we conclude that this improved model can be considered a powerful tool for the study of lanthanide complexesand their applications, such as the modeling of light conversion molecular devices.
beta2.gif" BORDER=0 ALIGN="middle">-diketone ligands. Assuch, we conclude that this improved model can be considered a powerful tool for the study of lanthanide complexesand their applications, such as the modeling of light conversion molecular devices.