C−H Activation by Iron‐Vanadium Bimetallic Oxide Cluster Anions FeV3O10− and FeV5O15−: A Comparison with Scandium‐Vanadium Oxide Clusters

Abstract

AbstractLate transition metal‐bonded atomic oxygen radicals (LTM−O⋅−) have been frequently proposed as important active sites to selectively activate and transform inert alkane molecules. However, it is extremely challenging to characterize the LTM−O⋅−‐mediated elementary reactions for clarifying the underlying mechanisms limited by the low activity of LTM−O⋅− radicals that is inaccessible by the traditional experimental methods. Herein, benefiting from our newly‐designed ship‐lock type reactor, the reactivity of iron‐vanadium bimetallic oxide cluster anions FeV3O10− and FeV5O15− featuring with Fe−O⋅− radicals to abstract a hydrogen atom from C2−C4 alkanes has been experimentally characterized at 298 K, and the rate constants are determined in the orders of magnitude of 10−14 to 10−16 cm3 molecule−1 s−1, which are four orders of magnitude slower than the values of counterpart ScV3O10− and ScV5O15− clusters bearing Sc−O⋅− radicals. Theoretical results reveal that the rearrangements of the electronic and geometric structures during the reaction process function to modulate the activity of Fe−O⋅−. This study not only quantitatively characterizes the elementary reactions of LTM−O⋅− radicals with alkanes, but also provides new insights into structure‐activity relationship of M−O⋅− radicals.