Resonance Raman spectra are reported for the carbon monoxide (CO) adduct of catalase formed from the reaction of peracetic acid or hydrogen peroxide with the azide adduct or catalase in the presence of CO. The expected three normal vibrations of the Fe–CO fragment are detected at 1,908, 593 and 543 cm−1 for the ν(C–O), δ(Fe–C–O) and ν(Fe–CO), respectively. The expected coordination or the phenolate group in this adduct is confirmed by the enhancement of an internal vibration of phenolate, ν19a at 1,515 cm−1, and an extraordinary intensity enhancement or the ν(Fe–CO) mode.
