CHEMISTRY PROFESSOR AND RESEARCH GROUP RECEIVE FUNDING TO CONTINUE QUEST FOR NEW MOLECULES

Joy Racowski '05, Annie Butler '05, Frank Mallory, Alyssa Boher, Sally Mallory and Colleen Regan

W. Alton Jones Professor of Chemistry Frank B. Mallory and his research group will continue the quest to create ever-longer molecules of a type of compound he has dubbed "phenacenes," with the support of an $80,000 grant from the Petroleum Research Fund, which is administered by the American Chemical Society. The compounds have potential applications as "molecular wires" in the emerging field of nanotechnology, but Mallory says that the prospect of his discovery being used in next-generation digital technology isn't his primary motivation; he calls the project "curiosity-driven research."

"It's the Everest effect," Mallory said. "Nobody has ever been able to make a molecule of this sort this long, and I think I know how to make them because of a chemical reaction I discovered. I want to see if it can be done."

Mallory's group currently includes postdoctoral associates Sally Mallory, A.B. '59, M.A. '60, Ph.D. '63, Colleen Regan, A.B. '95, Ph.D. Stanford '02; graduate students Xianlong Wang, Alyssa Bohen and Kirbi Krisfalusi (who is enrolled in the department's A.B./M.A. program), and undergraduates Annie Butler '05, Leila Foroughi '05, Joy Racowski '05 and Siobhan Lawler, a visiting student from Chestnut Hill College. The researchers are working on the synthesis of previously unknown and unprecedentedly elongated members of the "phenacenes" family of polycyclic aromatic hydrocarbons. When the work at Bryn Mawr began, the longest known phenacene had a total of six hexagonal rings of carbon atoms linked together.

The molecular structures of phenacenes have features similar to those found in graphite, in which there are large sheets of hexagonal rings of carbon atoms. Phenacenes may therefore be regarded as "graphite ribbons." Graphite conducts electricity: thus the potential of these compounds to be used to conduct electricity on a tiny scale at which metals cannot be used.

The Mallory research group has since succeeded in synthesizing a derivative of a phenacene with 11 rings, which is the current world's record (a symbolic representation of the carbon-atom skeleton of an 11-ring phenacene is shown below). The new grant will support the development of improved methods of synthesis that are designed to lead to much longer phenacenes.

Mallory developed a new synthesis strategy after the group hit a wall at an 11-ring molecule. "With the process we were using, the molecule became quite insoluble at 11 rings," Mallory explained. "We have to get it into solution to allow us to carry out the chemical reactions that will add more rings to the structure, so I examined the process and found three ways we could modify it."

With the new process, Mallory aims to create a series of molecules, each eight rings longer than the last. "We want to get to 35 rings," he said.

In mid-July the group celebrated three hard-won successes in the chemical steps along the synthesis pathway leading to the new and longer phenacenes. This created an unusually festive atmosphere in the lab.

"We don’t often have this much good news at one time," Mallory observed. "A lot of chemistry is disappointment — it consists of me being the cheerleader when students' procedures fall short of expectations. But we learn from all of it — even our failures."

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