Iron(I) and Iron(II) Boxmi Pincer Complexes: Coordination Chemistry and Catalytic Hydroboration of Nitriles

Iron(II) alkyl complexes of a terdentate bisoxazoline pincer ligand (“boxmi”) were synthesized, structurally characterized, and applied as precatalysts in the hydroboration of nitriles. By limiting the amount of borane, dinitriles could be partially hydroborated to selectively give the aminonitriles. Iron(I) complexes stabilized by dimerization were identified as an off-cycle species of the catalysis and characterized. Reactivity studies showed the iron(I) dimer reacting with ligands possessing at least some π-acceptor character, such as pyridine, Ph–C≡C–Ph and CO, to form monomeric adduct complexes that were isolated and structurally characterized.