“Basically, we were just sort of playing, trying to understand the reactions of hydrogen with metal complexes. It led to this,” said Professor Robert Morris, a chemist who studies the chemistry of compounds containing metal-carbon bonds-which are called organo-metals-who discovered a new type of bonding for hydrogen.

Organo-metals are prized for the role they play as catalysts in chemical reactions. Catalysts act as facilitators in chemicals reactions-speeding up their pace, but not taking part themselves in the reaction. Typically, only minute amounts of catalyst are needed to turbo-charge a sluggish reaction.

Morris had been fascinated by organo-metallic chemistry since his graduate days at the University of British Columbia. When he came to the University of Toronto in 1980, he began investigating replacements for rhodium-based catalysts, focusing on the element ruthenium because of its relatively low cost.

In the late 80s, the price for rhodium skyrocketed. It was now being used for catalytic converters in cars to reduce emission, and, not being a particularly abundant element, rhodium’s cost increased dramatically. This caused scientists to start looking into replacements for rhodium-based catalysts.

“Platinum metals-ruthenium, osmium, rhodium, iridium, palladium, and platinum-are really catalytically active metals and so are used in industry for all sorts of processes where you want to speed up the reaction. With the price of rhodium going up, people turned their attention to ruthenium, to see if it could to the same thing [as rhodium].”

One particular area where rhodium-based catalysts were useful was for hydrogenation reactions. Hydrogenation-the addition of hydrogen to materials-is fundamental to many organic processes. The synthesis of pharmaceuticals, for instance, relies heavily on the ability to transfer hydrogen from one molecule to the next.

“In industry, rhodium was used to transfer hydrogen from one molecule to another. Basically, it was used to make pharmaceutical intermediates,” said Morris, pointing to the use of rhodium-based compounds to catalyze the production of L-Dopa, a drug used to treat Parkinson’s disease.

Two important discoveries made by his group in the 80s and 90s about hydrogen aided Morris’s research. “They discovered compounds where hydrogen is coordinated to ruthenium in a soluble complex without the hydrogen-hydrogen bond breaking, which was unexpected because before then, whenever hydrogen reacted with anything, the hydrogen-hydrogen bond broke,” explained Morris. These papers were published in the Journal of the American Chemical Society.

“We discovered that when hydrogen is coordinated this way [without the bond breaking], it reacts with a base and you end up with a [negatively charged] hydrogen bonded to the metal and a [positively charged] hydrogen attached to the base, and they remained associated with each other at a really short distance.” This was a new type of bonding for hydrogen.

Morris’s group found that when the hydrogens were coordinated in a ruthenium-complex, both negatively and positively charged hydrogen could be transferred across the polar bonds of such organic molecules as ketones to produce alcohols, a common step in making many pharmaceutical processes.

His work on the basic chemistry of organo-metals continues apace. Morris’s goal is to produce organo-metallic compounds where the metal constituent is a cheap and abundant element, such as iron.