The tetrafluoropyridyl substituent of the N-heterocycle carbene ligand 1-(2,3,5,6-tetrafluoropyridyl)-3-benzylimidazolin-2-ylidene has been shown to undergo nucleophilic attack when coordinated to rhodium or silver. For the complex Cp *RhCl ₂{κC-(4-NC ₅F ₄)NC ₃H ₂N(CH ₂C ₆H ₅)} nucleophilic attack occurred at the less activated position, meta to the pyridyl ring nitrogen atom. In contrast, for the silver complex [Ag{κC-(4-NC ₅F ₅)NC ₅H ₅N(CH ₅C ₆H ₅)}] + nucleophilic attack occurred ortho to the pyridyl ring nitrogen atom.