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Borane-catalysed dinitrogen borylation by 1,3-B-H bond addition
Anaïs Coffinet1, Dan Zhang1, Laure Vendier1
1LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077 Toulouse cedex 4, France. antoine.simonneau@lcc-toulouse.fr.
Dalton Transactions (Cambridge, England : 2003)
|April 28, 2021
Summary
Tungsten-catalyzed borylation of dinitrogen using hydroboranes offers a mild route to boryldiazenido species. This study explores various hydroboranes, revealing catalytic retro-hydroboration and direct addition pathways for N2 functionalization.
Area of Science:
- Organometallic Chemistry
- Inorganic Chemistry
- Catalysis
Background:
- Previous work demonstrated Piers' borane catalyzed the borylation of a tungsten dinitrogen complex.
- The mild conditions of the prior reaction prompted an investigation into broader hydroborane scope.
- The hypothesis was that Piers' borane could catalyze 1,3-B-H bond additions of other hydroboranes to dinitrogen.
Purpose of the Study:
- To examine the borylation of ligated dinitrogen via 1,3-B-H bond addition using various hydroboranes.
- To investigate the catalytic potential of Piers' borane in these borylation reactions.
- To explore the reactivity of different hydroboranes, including dicyclohexylborane, diisopinocampheylborane, 9-borabicyclononane, and catecholborane.
Main Methods:
- Reaction of a tungsten dinitrogen complex with various hydroboranes under catalytic or non-catalytic conditions.
- Analysis of reaction products to determine the borylation pathways and species formed.
- Investigation of retro-hydroboration and direct addition mechanisms.
Main Results:
- Dicyclohexylborane and diisopinocampheylborane underwent retro-hydroboration to form monoalkylboranes, which then acted as borylating agents catalyzed by Piers' borane.
- 9-borabicyclononane added directly to the W-N[triple bond, length as m-dash]N unit without rearrangement.
- Catecholborane underwent 1,3-B-H bond addition without a catalyst, but multiple B-N bond formations were not achieved.
Conclusions:
- The catalytic system using Piers' borane is effective for the borylation of dinitrogen with specific hydroboranes via retro-hydroboration.
- Direct addition pathways exist for certain hydroboranes like 9-BBN and catecholborane.
- The methodology is limited to the formation of a single covalent B-N bond on the dinitrogen ligand.
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