UB Researchers Discover New Chemical Compound, As "Inert" Silicone Grease Engages In Surprise Reaction

BUFFALO, N.Y. -- A new chemical compound, produced by a reaction that the researchers say should never have happened, has been discovered by two University at Buffalo chemists.

A paper describing the work and the new compound, a silicone derivative of potassium organoindium hydride, was published this week in the British journal, Chemical Communications.

"We have formed a new species that's never been seen before," said Orville T. Beachley, Ph.D., UB chemistry professor and a co-author.

The surprising reaction, which occurred overnight, has taken the chemists far afield from their original work of growing crystals of chemicals used in manufacturing electronic materials. They are now exploring how the new compound might be used to mimic biological processes and to induce unusual solubility effects.

The reaction involved silicone grease, a chemical used extensively in laboratories. Seen almost universally as a stable, inert material, silicone grease is sometimes used to coat crystals as they grow, because it protects them without undergoing any chemical reaction.

But the UB research shows that silicone grease may not be the passive chemical most scientists believe it is, and they may need to exercise caution in using it.

"This should act as a warning about silicone grease," said Melvyn R. Churchill, Ph.D., professor of chemistry at UB and a co-author of the paper. "In the laboratory, silicone grease is used all the time, for example, to lubricate joints in glassware, but this is the first time it's been observed to react with a compound."

Characterized by a series of silicon-oxygen bonds, the new compound suggests possible utility as a good model for cell walls, or other models that mimic biological processes.

The chemists made their serendipitous discovery while trying to grow crystals of potassium salts of organoindium hydride compounds, chemicals used in the manufacture of electronic materials, such as semiconductors. They are extremely flammable when exposed to air, oxygen or water.

Churchill and Beachley managed to grow some crystals, but when they evaporated off the solvent, the crystal shattered. In their next attempt, they added silicone grease, commonly used to coat crystals and prevent the evaporation of solvent occluded in the crystals. Overnight, needle-shaped crystals formed.

"When we first looked at the structure, we were looking at a pattern that shouldn't have been there," said Churchill. "We thought we had something else, that maybe we had mislabeled our crystals or our computer files."

X-ray diffraction studies revealed a 14-member silicon-oxygen ring that acts like what the chemists describe as a pseudo-crown ether around the potassium ions.

"A crown ether is a carbon-oxygen molecule that forms a ring," explained Beachley. "There are lots of examples of this and people use them to solubilize metal salts, but never have we seen this with silicon and oxygen."

The chemists plan to try to use the unique reaction to induce unusual solubility effects, to prepare additional examples of these pseudo-crown ethers and to study their reaction chemistries. Other unexpected compounds could result, said Beachley.

In addition, they will be trying to figure out exactly how the reaction occurred.

"We're not sure if the silicon-oxygen ring we made is a minor component of the silicone grease, or if it was formed by components of silicone grease reacting with our compound," said Churchill.

The work, funded by the Office of Naval Research, was co-authored by doctoral candidates Charles H. Lake and Sun-Hua Leonard Chao.