Reactivity and Stability of a Ring-Expanded N-Heterocyclic Carbene Copper(I) Boryl Imidinate

R. S. C. Charman, Thomas Horsley Downie, Thomas H. Jerome, Mary F. Mahon, David J. Liptrot

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3 Citations (SciVal)


Frustrated Lewis pairs (FLPs) have evolved from a revolutionary concept to widely applied catalysts. We recently reported the ring-expanded N-heterocyclic carbene supported copper(I) boryliminomethanide, (6-Dipp)CuC(=NtBu)Bpin and noted it reacted with heterocumulenes in a fashion reminiscent of FLPs. We thus set out to explore its reactivity with a range of other substrates known to react with FLPs. This was undertaken by a series of synthetic studies using NMR spectroscopy, mass spectrometry, IR spectroscopy, and single crystal X-ray crystallography. (6-Dipp)CuC(=NtBu)Bpin was investigated for its reactivity towards water, hydrogen, and phenylacetylene. Its solution stability was also explored. Upon heating, (6-Dipp)CuC(=NtBu)Bpin decomposed to (6-Dipp)CuCN, which was characterised by SC-XRD and NMR spectroscopy, and pinBtBu. Although no reaction was observed with hydrogen, (6-Dipp)CuC(=NtBu)Bpin reacted with water to form (6-Dipp)CuC(=N(H)tBu)B(OH)pin, which was structurally characterised. In contrast to its FLP-reminiscent heterolytic cleavage reactivity towards water, (6-Dipp)CuC(=NtBu)Bpin acted as a Brønsted base towards phenyl acetylene generating (6-Dipp)CuCCPh, which was characterised by SC-XRD, IR, and NMR spectroscopy, and HC(=NtBu)Bpin
Original languageEnglish
Article number135
Issue number9
Early online date7 Sept 2022
Publication statusPublished - 30 Sept 2022

Bibliographical note

Funding Information:
D.J.L. thanks the Royal Society for the support of a University Research Fellowship. We wish to thank the University of Bath and MC for use of their analysis facilities. 2

Funding Information:
This research was funded by the Royal Society, grant number URF\R1\191066. The APC was funded by the kind contribution of MDPI.

Publisher Copyright:
© 2022 by the authors.


  • N-heterocyclic carbene
  • copper
  • frustrated Lewis pair

ASJC Scopus subject areas

  • Inorganic Chemistry


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