Kümper, Manuel and Westermair, Franz F. and Götz, Tobias and Gschwind, Ruth M. and Bauer, Jonathan O. (2025) Si-H Activation via Dynamic Permutational Isomerism: A Ligand-Directed Route to Dehydrogenative Coupling. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 64 (47). ISSN 1433-7851, 1521-3773
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Dehydrogenative coupling (DHC) of hydridosilanes with silanols under metal-free conditions provides a sustainable route to Si & horbar;O bond formation. Yet, the mechanistic origin of hydrogen release in such systems has remained unclear. Here, we show that dynamic permutational isomerism of pentacoordinate silicon intermediates is a key prerequisite for Si & horbar;H activation and H2 release. Using sterically tailored diaminohydridosilanes, we demonstrate that only ligands enabling access to axial hydride configurations facilitate Si & horbar;O coupling with productive H2 elimination. In contrast, N-tert-butyl substitution locks the hydride in the equatorial position and diverts reactivity toward Si & horbar;N bond cleavage. Multinuclear variable-temperature NMR spectroscopy, combined with quantum chemical calculations, reveals an equilibrium between equatorial and axial hydride configurations, enabling Berry pseudorotation and hydrogen evolution. These findings provide a mechanistic rationale for H2 release in hydridosilicates and establish ligand-directed isomerism as a general design principle for selective, metal-free Si & horbar;H activation.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SILICON-COMPOUNDS; NUCLEOPHILIC-SUBSTITUTION; OXIDATIVE CYCLIZATION; DENSITY FUNCTIONALS; KINETIC RESOLUTION; CRYSTAL-STRUCTURE; HARTREE-FOCK; BASIS-SETS; BOND; PENTACOORDINATE; Dehydrogenative coupling; Dynamic isomerism; NMR spectroscopy; Pentacoordinate intermediates; Silicon |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie Chemistry and Pharmacy > Institut für Organische Chemie > Arbeitskreis Prof. Dr. Ruth Gschwind |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 23 Sep 2026 04:16 |
| Last Modified: | 23 Sep 2026 04:16 |
| URI: | https://pred.uni-regensburg.de/id/eprint/66197 |
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