Reduction of poly(4-vinylpyridine)-coordinated ferriprotoporphyrin IX by N-benzyl-1,4-dihydronicotinamide in N,N-dimethylformamide

The reduction of a ferriprotoporphyrin IX–pyridine or poly(4-vinylpyridine) complex by N-benzyl-1,4-dihydronicotinamide in N,N-dimethylformamide to yield a corresponding ferro complex was studied kinetically and thermodynamically by spectral measurements. The reduction was confirmed to proceed via the intermediate. The rate of the reduction of the ferric iron was faster in the poly(4-vinylpyridine) complex than in the pyridine complex. This was caused by the adsorption of the reductant to the polymer ligand, causing the increase in the frequency factor of the reaction.