Reversible OH-bond activation and amphoterism by metal-ligand cooperativity of calix[4]pyrrolato aluminate
Most p-block metal amides irreversibly react with metal alkoxides when subjected to alcohols, making reversible transformations with OH-substrates a challenging task. Herein, we describe how the combination of a Lewis acidic square-planar-coordinated aluminum(III) center with metal-ligand cooperativ...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
20 Aug 2020
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| In: |
Chemical science
Year: 2020, Volume: 11, Issue: 35, Pages: 9611-9616 |
| ISSN: | 2041-6539 |
| DOI: | 10.1039/D0SC03602A |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1039/D0SC03602A Verlag, lizenzpflichtig, Volltext: https://pubs.rsc.org/en/content/articlelanding/2020/sc/d0sc03602a 
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| Author Notes: | Lukas M. Sigmund and Lutz Greb |
| Summary: | Most p-block metal amides irreversibly react with metal alkoxides when subjected to alcohols, making reversible transformations with OH-substrates a challenging task. Herein, we describe how the combination of a Lewis acidic square-planar-coordinated aluminum(III) center with metal-ligand cooperativity leverages unconventional reactivity toward protic substrates. Calix[4]pyrrolato aluminate performs OH-bond activation of primary, secondary, and tertiary aliphatic and aromatic alcohols, which can be fully reversed under reduced pressure. The products exhibit a new form of metal-ligand cooperative amphoterism and undergo counterintuitive substitution reactions of a polar covalent Al-O bond by a dative Al-N bond. A comprehensive mechanistic picture of all processes is buttressed by isolation of intermediates, spectroscopy, and computation. This study delineates how structural constraints can invert thermodynamics for seemingly simple addition reactions and invert common trends in bond energies. |
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| Item Description: | Gesehen am 28.10.2020 |
| Physical Description: | Online Resource |
| ISSN: | 2041-6539 |
| DOI: | 10.1039/D0SC03602A |