A new oxidation mechanism

Insight into the mechanisms of metal cluster reactions may help develop new synthetic technologies

Originally published online: February 2008

Conversion of the simple alkane, methane to the simplest alcohol, methanol is a valuable process in industry. Methanol is used extensively in fuels and feedstock; but it is difficult to produce on an industrial scale. Consequently there is considerable research interest in developing efficient methods to produce methanol.

However, within nature, a class of bacteria referred to as methanotrophs, mediate the reaction to convert methane to methanol. An enzyme in these bacteria, particulate methane monooxygenase (pMMO), is believed to catalyze the direct insertion of an oxygen atom into methane by using metal clusters.

Now, a team led by Sunney Chan from the Academia Sinica, Taiwan has tested the theory of metal clusters to understand this unique catalytic power. Chan proposed that a complex containing three copper atoms, in which the atomic charges vary, is the key to oxygen insertion. The team tested this theory by synthesizing a series of ligands to complex three copper atoms, mimicking the likely structure in pMMO.

Simultaneous computational experiments also support the mechanism proposed for insertion of oxygen atoms. Other simple alkanes were also tested. This research has provided valuable insight into the workings of pMMO and may provide inspiration for the development of future synthetic methods.

Reference
Chen P. P.-Y., Yang R. B.-G., Lee J. C.-M. & Chan S. I. Facile O-atom insertion into C-C and C-H bonds by a trinuclear copper complex designed to harness a singlet oxene. Proc. Nat. Acad. Sci. U.S.A. 2007, 104, 14570–14575