Revisiting the putative ferryl tilting mode of oxidized cytochrome c oxidase with density functional vibrational analyses of model complexes

A study was conducted to examine Fe(IV)=O model complexes using energy second derivatives determined with nonlocal density functional theory using full vibrational analyses. Theoretical methods were utilized in the study. These methods supported full geometry optimizations, spin-unrestricted computations and analytical frequencies. Results suggested that the 356 cm(super -1) band of CcO is a ferryl tilting mode.