Renewable energy systems will benefit from molecules that mimic natural processes, say Swedish researchers.

Sascha Ott and colleagues at the University of Uppsala have made a synthetic complex that can mimic natural proton-reducing enzymes. 

The group aimed to replicate and analyse natural iron and nickel catalysts by building small model complexes. 'If we can manage to make synthetic complexes that function at similar potential and under similar conditions, an abundant and renewable future energy supply is in reach,' said Ott. 

They made a model of the iron hydrogenase active site containing a proton and a hydride. The electron-donating ligands at the diiron core carry the hydride, and an adt (azadithiolate) linker carries the proton.

This double protonated structure is reduced at a mild potential that is considerably more positive than that of any other iron hydrogenase mimic ever reported. It also resembles an intermediate closer to the hydrogen formation event than other model complexes that carry either a hydride or a proton only. 

Building a model like this will give spectroscopic references for natural enzymes, which will help unravel how enzymes work. 

Ott wants to continue the work by designing better catalysts for use in renewable energy generation. Aspects to be considered are stability of the catalyst, adjustment of the required reduction potential to even more positive values and increasing the turnover numbers. Another interest is the driving of the catalytic reduction of protons by the action of light.  

Elinor L Richards