Husband-Wife Research Team Honored
By International Chemistry Organization
Frank (second from left) and Sally (second from right) Mallory in the lab with members of their research team in 2004
After 40 years of marriage, the Mallorys still have chemistry — so much that chemists around the world recognize it. The pair — W. Alton Jones Professor of Chemistry Frank Mallory and his wife and research partner Sally Mallory, a senior lecturer in the University of Pennsylvania’s chemistry department who holds A.B., M.A. and Ph.D. degrees from Bryn Mawr — were invested as fellows of the Inter-American Photochemical Society at the organization’s annual meeting in Salvador, Brazil, in mid-June.
The fellowship, which recognizes "outstanding lifetime scientific achievements in the photochemical sciences," has been awarded to only 12 other scientists since it was instituted in 1994. The Mallorys are the first team to win the honor. Their scientific partnership predates their marriage: they began publishing together in 1962.
"It's unusual for a husband and wife to be an integral team doing chemistry," Frank Mallory observes, "and we've always been quite noticeable because of it. Our partnership has made professional life more pleasant because we always travel to meetings and conferences together, and we can treat some of that travel as vacation time."
"It's unusual for a research team to stay together this long, too," Sally Mallory adds.
The couple has pursued several varied avenues of research, but they are most celebrated for their investigations of the so-called "Mallory reaction," which Frank discovered serendipitously as a graduate student at the California Institute of Technology in 1955. The Mallory reaction became a staple of organic chemistry, used by thousands of chemists to synthesize new compounds.
"When I came to Bryn Mawr in 1957, I started trying to understand everything about this reaction," Frank says. "Sally was the first person ever to begin a systematic study of its scope."
"My Ph.D. thesis examined 20 systematically chosen molecules that might undergo the Mallory reaction," Sally explains. "Twenty years later, Frank and I were asked to write a review article summarizing the state of research into the reaction for a prestigious book series, and so many chemists had adopted it that our chapter dealt with 2,000 examples and ran to 450 pages."
The Mallory reaction opened up new possibilities for creating polycyclic aromatic compounds – molecules based on fused hexagonal rings of carbon atoms.
"There are thousands of compounds that contain one six-membered carbon ring," Frank explains. "They tend to have unusual properties, and people are very interested in getting compounds with more of these rings fused together. Synthesizing a compound with two rings is quite difficult, so the conventional wisdom when I was in graduate school was that fusing three rings together would be very much more difficult."
"What our reaction does," Frank continues, "is to take two six-membered rings to serve as the first and third rings, and connect them together by a two-carbon unit. Shining ultraviolet light on the resulting molecule creates a new six-membered ring in the middle, using the two-carbon unit and sharing a pair of carbons from each of the first and third rings. Using this approach, synthesizing a three-ring molecule is now much easier than making a two-ring molecule."
The Mallorys' current research in the field aims to develop methods for creating molecules in which multiple carbon rings are linked together in a zig-zag configuration. These molecules are expected to have properties similar to those of graphite, which is composed of millions of planar sheets of carbon atoms bonded in fused hexagonal rings. Ribbon-like molecules of linked carbon rings may, like graphite, conduct electricity, opening the possibility of "nanowires" that are only one molecule wide and one atom thick.
Their research team, which typically includes undergraduates, graduate students and the occasional postdoctoral fellow, has succeeded in creating a compound that fuses together 11 rings — by far the longest such molecule ever synthesized. They are at work on ways to add still more rings.
Computational methods have become very powerful in modeling chemical reactions to understand their mechanisms and in making predictions of new reactions. This development has changed what Sally calls "wet chemistry" — laboratory experimentation — dramatically over the course of the Mallorys' careers. "You can now get more and more theoretical information that leads to better and better experiments," she says. But the Mallorys agree that experimental chemistry remains important, despite its being largely a process of trial and error, with a much higher proportion of failure than triumph. The field requires patience and determination — qualities that appear to be useful in a marriage as well.
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