DFT mechanisms for terminal to mu hydride isomerisation in synthetic analogues of FeFe Hydrogenase

What is it about?

An energetically viable reaction mechanism is provided by DFT computations for the unimolecular rearrangement affecting the terminal hydride isomer of synthetic models of FeFe Hydrogenase cofactor (crucial intermediate for H2 formation in the natural enzyme and reactive towards protons also in synthetic analogues) which turns it into FeFe bridging isomer (not formed in the enzyme and less reactive or not reactive toward protons).

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Why is it important?

This is the first time a justification has been provided for one of the most problematic flaws affecting synthetic models of FeFe Hydrogenase, i.e., the instability (thermodynamic and kinetic) of their terminal (Fe) protonated forms. The identification of an energetically viable pathway of interconvertion to "inactive" or less reactive protonated isomers (FeFe bridging) is the first step to try to design new catalysts for H2 production/oxidation, based on cheap metals such as iron.