A T-shaped Ni[κ²-(CF₂)₄–] NHC complex: unusual C_sp3–F and M–C^Fbond functionalization reactions

A T-shaped octafluoronickelacyclopentane-NHC complex is prepared and characterized. While the solid-state structure includes a weak isopropyl-CH₃ agostic interaction, the reactivity of this complex with Lewis- and Brønsted acids is clearly enhanced by its low coordination number. Reaction with Me₃SiOTf, for example, yielded a rare metal-heptafluorocyclobutyl complex whereas carboxylic acids gave substitution at the α-carbon and/or Ni-C^F bond protonolysis to afford thermally robust 4<i>H</i>-octafluorobutyl Ni complexes.