Cobaltocene Polymers for Low-Potential Enzymatic Electrocatalysis

Redox-active polymers (or, "redox polymers") have gained attention in the field of enzymatic electrocatalysis due to their ability to immobilize relatively large quantities of electronically wired oxidoreductase enzymes on electrode surfaces. The use of enzymes for the electroenzymatic synthesis of chemicals is an interesting future prospect, although the availability of redox polymers for low-potential electroenzymatic reactions has been limited until recently. This chapter details the preparation of a cobaltocene-containing redox polymer [cobaltocene-modified branched poly(ethylenimine), "Cc-BPEI"], which has been used for the electroenzymatic synthesis of chemicals including molecular hydrogen (H₂), formate (HCOO^-), reduced nicotinamide adenine dinucleotide (NADH), and ammonia (NH₃). The coupling of this redox polymer with an [FeFe]-hydrogenase for the electroenzymatic synthesis of H₂ is demonstrated.