Electronic structure description of the cisMoOS unit in models for molybdenum hydroxylases

The electronic structures of the cis-MoOS unit is studied by using S K-edge X-ray absorption spectroscopy (XAS) and vibrational spectroscopies coupled with bonding calculations. The electronic structure of the oxidized enzyme site has played a role in polarizing a substrate carbon center for nucleophilic attack by metal activated water and has acted as an electron sink in the two-electron oxidation of substrates.