Water-soluble and air-stable [2Fe-2S]-metallopolymers: A new class of electrocatalysts for H₂ production via water splitting

[2Fe–2S] organometallic complexes are effective electrocatalysts for the reduction of weak acids in acetonitrile to generate molecular hydrogen (H₂) (hydrogen evolution reaction, HER). Incorporation of such a [2Fe–2S] catalytic site into metallopolymers has been achieved using atom transfer radical polymerization (ATRP). These well-defined polymers have been structurally characterized by SEC, ¹H NMR and IR spectroscopy. These metallopolymers catalyze the electrochemical reduction of acetic acid in acetonitrile. In addition, [2Fe–2S] metallopolymers appended with amino groups were shown to be water-soluble and potent electrocatalysts for H₂ production at pH 7. In addition to the exceptional activity of these [2Fe–2S] metallopolymers in water, these catalysts maintain catalytic activity in air unlike comparable molecular catalysts.