Paramagnetic complexes of iron (III), manganese (II), and cobalt (II) protoporphyrins IX and apohemoproteins react with nitric oxide to form spectroscopically distinct compounds. Optical and electron paramagnetic resonance (EPR) studies suggest that a l-electron transfer between nitric oxides and metal ions which occurs in these reactions results in the formation of spin-paired complexes of the...

The difference in electrostatics and reduction potentials between manganese ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP) and manganese meta-tetrakis(N-ethylpyridinium-3-yl)porphyrin (MnTE-3-PyP) is a challenging topic, particularly because of the high likelihood for their clinical development. Hence, a detailed study of the protolytic and electrochemical speciation of Mn(II-IV)T...

In the natural environment, manganese is found as reduced soluble or adsorbed Mn(II) and insoluble Mn(III) and Mn(IV) oxides. Mn oxidation has been reported in various microorganisms. Several possible pathways, indirect or direct, have been proposed. A wider variety of Mn-reducing microorganisms, from highly aerobic to strictly anaerobic, has been described. The mechanisms of Mn reduction can b...