An air-stable d9 nickel(I) catenate: stabilisation of monovalent nickel by interlocked macrocyclic ligands

The catenand cat-30 forms a d9 nickel(I) complex by electroreduction of the nickel(II) precursor, Ni(cat-30)2+; owing to the particular arrangement of the co-ordinating subunits and to the special topology of the ligand, the nickel(I) complex displays exceptional redox stability.