Insight into importance of ligand geometry on catalytic performance could boost the alkane oxidation industry, report researchers in the UK.

Non-heme iron based catalysts are known to have unusually high activity and product selectivity for alkane oxidation with hydrogen peroxide. However, catalytic efficiencies are often low. George Britovsek and colleagues at Imperial College London improved this efficiency by exploring novel catalysts for selective alkane oxidation. 

Britovsek and his team used metals such as Fe, Mn and Co to make non-heme catalysts with different ligand geometries. The complexes contained two labile (unstable) co-ligands and a tetradentate nitrogen donor ligand. 

The researchers found that the most efficient catalysts had the labile co-ligands in a cis orientation. This highlights the importance of tetradentate ligands that enforce rigid cis coordination geometry around the metal centre, said Britovsek. 

The next goal is to develop a long-lived catalyst that selectively converts alkanes to alcohols with high activity with 100 per cent conversion. 'Valuable lessons have been learned here which will dictate the path forward,' said Britovsek.   

Sarah Dixon