To Bend or Not To Bend: Experimental and Computational Studies of Structural Preference in Ln(Tp iPr 2 ) 2 (Ln = Sm, Tm) - INSA Toulouse - Institut National des Sciences Appliquées de Toulouse Access content directly
Journal Articles Inorganic Chemistry Year : 2014

To Bend or Not To Bend: Experimental and Computational Studies of Structural Preference in Ln(Tp iPr 2 ) 2 (Ln = Sm, Tm)

Abstract

The synthesis and characterization of Ln(TpiPr2)2 (Ln = Sm, 3Sm; Tm, 3Tm) are reported. While the simple 1H NMR spectra of the compounds indicate a symmetrical solution structure, with equivalent pyrazolyl groups, the solid-state structure revealed an unexpected, “bent sandwich-like” geometry. By contrast, the structure of the less sterically congested Tm(TpMe2,4Et)2 (4) adopts the expected symmetrical structure with a linear B–Tm–B arrangement. Computational studies to investigate the origin of the unexpected bent structure of the former compounds indicate that steric repulsion between the isopropyl groups forces the Tp ligands apart and permits the development of unusual interligand C–H···N hydrogen-bonding interactions that help stabilize the structure. These results find support in the similar geometry of the Tm(III) analogue [Tm(TpiPr2)2]I, 3Tm+, and confirm that the low symmetry is not the result of a metal–ligand interaction. The relevance of these results to the general question of the coordination geometry of MX2 and M(C5R5)2 (M = heavy alkaline earth and Ln(II), X = halide, and C5R5 = bulky persubstituted cyclopentadienyl) complexes and the importance of secondary H-bonding and nonbonding interactions on the structure are highlighted.
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Dates and versions

hal-01969571 , version 1 (04-01-2019)

Identifiers

  • HAL Id : hal-01969571 , version 1

Cite

Aurélien Momin, Lee Carter, Yi Yang, Robert Mcdonald, Stéphanie Essafi (née Labouille), et al.. To Bend or Not To Bend: Experimental and Computational Studies of Structural Preference in Ln(Tp iPr 2 ) 2 (Ln = Sm, Tm). Inorganic Chemistry, 2014, 53 (22), pp.12066-12075. ⟨hal-01969571⟩
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