A Highly Active Bidentate Magnesium Catalyst for Amine‐Borane Dehydrocoupling: Kinetic and Mechanistic Studies

Ried, Alexander; Taylor, Laurence; Geer, Ana; Williams, Huw; Lewis, William; Blake, Alexander; Kays, Deborah Lorraine

Abstract

A magnesium complex (1) featuring a bidentate aminopyridinato ligand is a remarkably selective catalyst for the dehydrocoupling of amine-boranes. This reaction proceeds to completion with low catalyst loadings (1 mol%) under mild conditions (60 °C), exceeding previously reported s-block systems in terms of selectivity, rate, and turnover number (TON). Mechanistic studies by in situNMR analysis reveals the reaction to be firstorder in both catalyst and substrate. A reaction mechanism is proposed to account for these findings, with the high TON of the catalyst attributed to the bidentate nature of the ligand, which allows for reversible deprotonation of the substrate and regeneration of 1as a stable resting state.

Citation

Ried, A., Taylor, L., Geer, A., Williams, H., Lewis, W., Blake, A., & Kays, D. L. (2019). A Highly Active Bidentate Magnesium Catalyst for Amine‐Borane Dehydrocoupling: Kinetic and Mechanistic Studies. Chemistry - A European Journal, 25(27), 6840-6846. https://doi.org/10.1002/chem.201901197

• Journal Article Type: Article
• Acceptance Date: Mar 15, 2019
• Online Publication Date: Mar 15, 2019
• Publication Date: May 10, 2019
• Deposit Date: Apr 18, 2019
• Publicly Available Date: Mar 16, 2020
• Journal: Chemistry - A European Journal
• Print ISSN: 0947-6539
• Electronic ISSN: 1521-3765
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 25
• Issue: 27
• Pages: 6840-6846
• DOI: https://doi.org/10.1002/chem.201901197
• Keywords: dehydrocoupling; magnesium; hydrogen storage; amido ligands; homogeneous catalysis
• Public URL: https://nottingham-repository.worktribe.com/output/1829634
• Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201901197
• Contract Date: Apr 18, 2019