A stable ring-expanded NHC-supported copper boryl and its reactivity towards heterocumulenes

Thomas M. Horsley Downie, Rex S.C. Charman, Jonathan W. Hall, Mary F. Mahon, John P. Lowe, David J. Liptrot

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10 Citations (SciVal)


Reaction of bis(pinacolato)diboron with (6-Dipp)CuOtBu generates a ring-expanded N-heterocyclic carbene supported copper(i) boryl, (6-Dipp)CuBpin. This compound showed remarkable stability and was characterised by NMR spectroscopy and X-ray crystallography. (6-Dipp)CuBpin readily dechalcogenated a range of heterocumulenes such as CO2, isocyanates and isothiocyanates to yield (6-Dipp)CuXBpin (X = O, S). In the case of CO2 catalytic reduction to CO is viable in the presence of excess bis(pinacolato)diboron. In contrast, in the case of iso(thio)cyanates, the isocyanide byproduct of dechalcogenation reacted with (6-Dipp)CuBpin to generate a copper(i) borylimidinate, (6-Dipp)CuC(NR)Bpin, which went on to react with heterocumulenes. This off-cycle reactivity gives selective access to a range of novel boron-containing heterocycles bonded to copper, but precludes catalytic reactivity.

Original languageEnglish
Pages (from-to)16336-16342
Number of pages7
JournalDalton Transactions
Issue number44
Publication statusPublished - 28 Nov 2021

Bibliographical note

Funding Information:
DJL thanks the Royal Society for the support of a University Research Fellowship. We acknowledge financial support from the EPSRC Centre for Doctoral Training in Catalysis (EP/L016443/1) for JWH.

ASJC Scopus subject areas

  • Inorganic Chemistry


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