Frustrated Lewis Pair Chemistry Enables N2 Borylation by Formal 1,3-Addition of a B−H Bond in the Coordination Sphere of Tungsten |
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Authors: | Anaïs Coffinet Dr David Specklin Dr Laure Vendier Prof Dr Michel Etienne Dr Antoine Simonneau |
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Institution: | LCC-CNRS, UPS, Université de Toulouse, CNRS, 205 route de Narbonne, BP44099, 31077 Toulouse Cedex 4, France |
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Abstract: | The first example of a formal 1,3-B−H bond addition across the M−N≡N unit of an end-on dinitrogen complex has been achieved. The use of Piers’ borane HB(C6F5)2 was essential to observe this reactivity and it plays a triple role in this transformation: 1) electrophilic N2-borylation agent, 2) Lewis acid in a frustrated Lewis pair-type B−H bond activation, and 3) hydride shuttle to the metal center. This chemistry is supported by NMR spectroscopy and solid-state characterization of products and intermediates. The combination of chelate effect and strong σ donation in the diphosphine ligand 1,2-bis(diethylphosphino)ethane was mandatory to avoid phosphine dissociation that otherwise led to complexes where borylation of N2 occurred without hydride transfer. |
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Keywords: | boranes dinitrogen frustrated Lewis pairs phosphines tungsten |
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