When Electrons Step in: Polarizing Effects Explored with Triisobutylaluminum

High-resolution X-ray diffraction data of triisobutylaluminum were collected, and unexpected structural features were observed, hinting toward yet unnoticed polarization effects. To approach these, a multipole refinement using the Hansen and Coppens method, followed by a topological analysis using B...

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Bibliographic Details
Published in:Inorganic chemistry 2021-03, Vol.60 (5), p.2872-2877
Main Authors: Hermann, Andreas, Münch, Annika, Orr, Samantha A., Herbst-Irmer, Regine, Mulvey, Robert E., Strohmann, Carsten, Stalke, Dietmar
Format: Article
Language:English
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Summary:High-resolution X-ray diffraction data of triisobutylaluminum were collected, and unexpected structural features were observed, hinting toward yet unnoticed polarization effects. To approach these, a multipole refinement using the Hansen and Coppens method, followed by a topological analysis using Bader’s quantum theory of atoms in molecules, was employed. The electron localization function based on density functional theory calculations supported the experimental findings. Thereby, unobserved electron shifts within the isobutyl group become detectable. It is shown that the impact of this electron shift is dependent mainly on whether the i Bu substituent of the homoleptic triisobutylaluminum dimer [Al i Bu3]2 (1) is connected by a directional (σ) or a multicenter (μ) bond to the metal. The effect found is assumed not only to be of paramount importance for organoaluminum compounds, widely used in synthesis and in the industrial value chain, but also to be present in organometallic chemistry in general.
ISSN:0020-1669
1520-510X
DOI:10.1021/acs.inorgchem.0c03471