Hexacoordinate oxy-globin models Fe(Por)(NH3)(O-2) react with NO to form only the nitrato analogs Fe(Por)(NH3)(eta(1)-ONO2), even at similar to 100 K

The oxy-globin models Fe(Por)(NH3)(O-2), prepared by sequential reactions of O-2 (O-18(2)) and NH3 with thin porous layers of Fe-II(Por), react with NO ((NO)-N-15) at 80-100 K to form only the low-spin nitrato complexes Fe(Por)(NH3)(eta(1)-ONO2), thus implying that peroxynitrite intermediates, if formed, must undergo very facile isomerization to the nitrato analog.