Nuclear forward scattering (NFS) of synchrotron radiation was applied to in
vestigate the electronic and magnetic properties of (i) the diamagnetic "pi
cket-fence" porphyrin FeO2(SC6HF4)(TPpivP), which is a model for oxygenated
hemoglobin and myoglobin and (ii) the paramagnetic "picket-fence" porphyri
n [Fe(CH3COOH)(TPpivP)](-), which is a model for the ferrous state of the p
rosthetic group, termed P460, of the multi-heme enzyme hydroxylamine oxidor
eductase from the bacterium Nitrosomonas europeae.