Nuclear Resonance Vibrational Spectroscopic Definition of Peroxy Intermediates in Nonheme Iron Sites

作者：Sutherlin Kyle D; Liu Lei V; Lee Yong Min; Kwak Yeonju; Yoda Yoshitaka; Saito Makina; Kurokuzu Masayuki; Kobayashi Yasuhiro; Seto Makoto; Que Lawrence Jr^*; Nam Wonwoo^*; Solomon Edward I^*

来源：Journal of the American Chemical Society, 2016, 138(43): 14294-14302.

DOI：10.1021/jacs.6b07227

Fe-III-(hydro)peroxy intermediates have been isolated in two classes of mononuclear nonheme Fe enzymes that are important in bioremediation: the Rieske dioxygenases and the extradiol dioxygenases. The binding mode and protonation state of the peroxide moieties in-these intermediates are not well-defined, due to a lack of vibrational structural data. Nuclear resonance vibrational spectroscopy (NRVS) is an important technique for obtaining vibrational information on these and other intermediates, as it is sensitive to all normal modes with Fe displacement. Here, we present the NRVS spectra of side-on Fe-III-peroxy and end-on Fe-III-hydroperoxy model complexes and assign these spectra using calibrated DFT calculations. We then use DFT calculations to define and understand the changes in the NRVS spectra that arise from protonation and from opening the Fe-O-O angle. This study identifies four spectroscopic handles that will enable definition of the binding mode and protonation state of Fe-III-peroxy intermediates in mononuclear nonheme Fe enzymes. These structural differences are important in determining the frontier molecular orbitals available for reactivity.

• 出版日期2016-11-2