A polyene-based polymer functionalized with a model of [FeFe]-hydrogenase and film electrodes assembled from the polymer via spin-coating

A diiron hexacarbonyl complex possessing an alkynyl group as a model complex of the diiron sub-unit of [FeFe]-hydrogenase was polymerized under the catalysis of WCl6-SnPh4. The polymer (Poly-{Fe2}) functionalized with {Fe2(CO)6} units which is dominated by cis-form was fully characterised using FTIR, NMR, SEM, TEM, and TGA techniques. Through modifying the monomer, the properties, for example, solubility, of the resultant polymer could be tuned and much larger molecule weight, which was estimated as 7.93 × 105 g mol−1 using static light scattering technique was achieved without compromising its solubility. Spin-coating the functionalized polymer onto the surface of vitreous carbon electrode with or without multi-wall carbon nanotubes (MWCNTs) produced film electrodes which show electrochemical responses. Adding MWCNTs into the film enhances significantly the electrochemical response probably via not only improving the conductivity of the film, but also the increase in its effective surface area after being doped with MWCNTs.

► Polymerizing a diiron mimic achieved a polymer related to [FeFe]-hydrogenase. ► Film electrode was assembled using the polyene-based polymer via spin-coating. ► The film electrode showed electrochemical catalysis on proton reduction.