The influence of a S-to-S bridge in diiron dithiolate models on the oxidation reaction: a mimic of the H(air)(ox) state of [FeFe]-hydrogenases.

Two-electron oxidation of a diiron complex (1) containing a bulky S-to-S bridge with an exocyclic carbonyl group affords [1(OH)](+), which replicates the coordination structure and electronic configuration of H(air)(ox), and the chemically reversible reaction between 1 and [1(OH)](+) mimics the bioprocess of interconversion of the inactive H(air)(ox) and the active Hred states of the [FeFe]-hydrogenases.