Structural differences of the iron–dioxygen moiety of haemoprotein models with and without an axial hindered base as revealed by 17O NMR and FTIR spectroscopy in solution

Abstract

The N–H stretching vibrations of the oxygenated ‘hybrid’ haemoprotein models with an axial hindered base indicate that there is no conventional hydrogen bond with the terminal oxygen of the Fe–O₂ moiety, contrary to the models with an axial unhindered base; however, the Fe–O₂ moiety is highly polarizable as indicated by ¹⁷O NMR spectroscopy.