Lanthanide Contraction in Lanthanide Organic Frameworks: A Theoretical and Experimental Study
Gustavo S Silva1, José Diogo L Dutra1, Nivan B da Costa1
1Pople Computational Chemistry Laboratory, Department of Chemistry, Federal University of Sergipe-UFS, 49100-000 São Cristóvão, SE, Brazil.
Abstract:
In this work, the lanthanide (Ln) contraction phenomenon has been analyzed for three-dimensional structures in the solid state. We chose to study an isostructural series of lanthanide organic frameworks (LOFs) of formula [Ln2(C4H4O4)3(H2O)2]·H2O and 14 crystallographic structures (except promethium complex). The analysis of Ln contraction was made by analyzing the sum of all Ln-O bond lengths and the sum of all O-O distances, for the oxygen atoms of the coordination polyhedra, calculated with different semiempirical quantum mechanical models. The ∑Ln-O and ∑O-O for this LOF can be fit to a second-order polynomial. Based on the crystallographic structures, it is concluded that the phenomenon of Ln contraction is observed. Our results also suggest that the semiempirical Sparkle/PM3 and Sparkle/RM1 models reproduce the Ln contraction phenomenon well, and similar fits were obtained for ∑Ln-O and ∑O-O bond lengths.
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