Resonance Raman spectra of methemoglobin derivatives. Selective enhancement of axial ligand vibrations and lack of an effect of inositol hexaphosphate

Resonance Raman spectra have been obtained for the OH-, N; and Fderivatives of nethsroglabin by excitaticn in the 550-650 nm region.A selective enhancement with excitation in the chal:ge transfer baOOs is ob-.served for peaks at 413 an -l, 497 an -l and a doublet at 4 71 and 443 an -l in theN;, aC and F-CXXIplexes, respectively.These peaks are assigned to Fe-axial ligand stretches on the basis of: 1.A 20 an -1 shift of the .497 an-1 peak of the hydroxide <Xllplex to lower energy on isotopic substituticn of 18 aC for 16 oH-; 2. The p:rox:i.mi ty of the 413 an -l Raman peak to .the 421 an -1 IR peak previously assigned to the Fe-N; stretch in a IOOdel