UC Davis chemists have shown that ethylene, a gas that is important as a raw material in industrial chemistry and as a hormone that controls fruit ripening, can bind reversibly to tin atoms.

A paper on the research appeared in the Sept. 25 edition of the journal Science.

Chemistry professor Philip Power, the senior author, said he did not foresee an immediate application for the discovery. But he said it will contribute in general to understanding ethylene catalysis, with possible implications for industrial catalysis if similar behavior can be shown for a cheap metal like aluminum.

Ethylene has long been known to react with transition metals such as iron or copper, but was not thought to react reversibly with metals such as tin or aluminum.

“Reversibility is important, because it shows that it could be involved in catalytic processes,” Power said.

Catalysts are materials that allow chemical reactions to proceed more efficiently, often by forming temporary intermediate structures. Some plants release ethylene to control fruit ripening, although no known biological molecules include a tin atom.

In the experiment, graduate student Yang Peng passed ethylene at room temperature and normal atmospheric pressure through a compound made up of two tin atoms bonded to each other and also to rings of carbon atoms. The green tin compound turned yellow in the presence of ethylene, and a new compound could be crystallized out. Slight heating of the mixture reversed the reaction and released ethylene again.

Power said the result was unexpected, but noted, “You investigate the reactions, and sometimes you find something interesting.”

“It’s serendipity, but you have to be looking and willing to follow it up,” he said.

Other contributors to the research: postdoctoral scientists Xinping Wang and Bobby Ellis, and X-ray crystallographer James Fettinger.

— Andy Fell