Protonolysis of Fe–C bonds of a diiminopyridineiron(II) dialkyl complex by acids of different strengths: Influence of monoanionic ligands on the spectroscopic properties of diiminopyiridine-FeY2 complexes

The reaction of the dialkyliron complex [Fe(CH2SiMe3)2(MesBIP)] (MesBIP = 2,6-bis((N-mesityl)acetimidoyl)pyridine) with protic acids (HY) of different strengths (Y = C6F5O, CF3CO2, Cl, CF3SO3) invariably leads to the cleavage of both Fe–C bonds, independent of the Fe/HY ratio used (either 1:2 or 1:1), affording the corresponding complexes [FeY2(MesBIP)]. Relevant spectroscopic features of these compounds, such as paramagnetic 1H NMR shifts and UV–Vis absorption bands, exhibit a marked dependence on the nature of Y.