Dual diborane(4) reactivity: Lewis acid to bind Lewis-basic substrates and electron donor for substrate reduction through stimulated diborane-substrate electron transfer

Electron-rich ditriflato- and dibromido-diborane(4) molecules with bridging guanidinate substituents readily eliminate triflate/bromide to give monocationic diboranes displaying a dual reactivity as Lewis acids and electron donors. In this work, we report unprecedented reaction sequences in which py...

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Main Authors: Haas, Lea (Author) , Kistner, Lucas (Author) , Roesky, Eva (Author) , Mailänder, Luca (Author) , Kaifer, Elisabeth (Author) , Himmel, Hans-Jörg (Author)
Format: Article (Journal)
Language:English
Published: April 15, 2025
In: Chemistry - a European journal
Year: 2025, Volume: 31, Issue: 22, Pages: 1-7
ISSN:1521-3765
DOI:10.1002/chem.202500709
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1002/chem.202500709
Verlag, kostenfrei, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.202500709
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Author Notes:Lea Haas, Lucas Kistner, Eva A.M. Roesky, Luca Mailänder, Elisabeth Kaifer, and Hans-Jörg Himmel
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Summary:Electron-rich ditriflato- and dibromido-diborane(4) molecules with bridging guanidinate substituents readily eliminate triflate/bromide to give monocationic diboranes displaying a dual reactivity as Lewis acids and electron donors. In this work, we report unprecedented reaction sequences in which pyrazine derivatives are first coordinated to the diborane. These coordination compounds are intensely coloured due to electronic excitations from an electron in the B−B bond to a pyrazine π* orbital. Then, in a second, separate step, electron transfer is triggered by pyrazine methylation, simply by addition of MeOTf, increasing the acceptor strength of the coordinated pyrazine unit. Moreover, our experiments show that electron transfer could be triggered by reaction with an excess of pyrazine. We applied a selection of pyrazine derivatives and studied various mono- and dicationic pyrazine-diborane complexes to evaluate the scope of this novel metallomimetic diborane reactivity.
Item Description:Zuerst verfügbar: 03. März 2025
Gesehen am 07.08.2025
Physical Description:Online Resource
ISSN:1521-3765
DOI:10.1002/chem.202500709