Multiscale Model for a Metal–Organic Framework: High-Spin Rebound Mechanism in the Reaction of the Oxoiron(IV) Species of Fe-MOF-74

Abstract

We performed ONIOM QM/MM calculations to understand how ethane is hydroxylated and ethanol is converted to acetaldehyde by an oxoiron(IV) species generated within an iron-containing metal–organic framework called Fe-MOF-74. The calculations showed that the ethane hydroxylation proceeds via a high-spin rebound mechanism. The conversion of ethanol into acetaldehyde should occur more favorably via H-abstraction from the O–H bond than via C–H cleavage, although the O–H bond of ethanol is stronger than the C(1)–H bond. This trend can be rationalized by the effect of proton-coupled electron transfer, which stabilizes the transition state for O–H cleavage.