NEW FACULTY: JONAS GOLDSMITH BROADENS PERSPECTIVES ON CHEMISTRY RESEARCH

As supplies of polluting, expensive and nonrenewable fossil-based fuels dwindle, scientists are studying the potential of hydrogen as a clean, affordable and renewable source of energy. Research on hydrogen energy has typically focused on water, an inexpensive and universally available supply of hydrogen. When extracted from water, hydrogen may be used to generate heat, electricity or other forms of power. While the process of converting water into hydrogen energy is simple in principle, it has proven to be stubbornly problematic in practice. Scientists are still working to free hydrogen from water economically and efficiently.

Jonas I. Goldsmith, who joined Bryn Mawr College this year as an assistant professor of physical chemistry, is trying to find a novel solution to this problem. "The idea is to convert solar energy into a form that can be stored or transported: using it to split water molecules to generate hydrogen. I'm investigating a variety of transition-metal complexes as catalysts for this process, catalysts that have the right oxidation and reduction properties to make it happen," he explains.

Goldsmith's work may someday advance to a point when hydrogen might replace gas, oil or coal as society's primary energy source - clean, renewable and cost-efficient.

Inspired Insights

Goldsmith first recognized chemistry's beneficial promise in high school. "Chemistry was the first science class that actually seemed like real science to me," he recalls. He was fortunate to have had inspiring mentors along the way - as a chemistry major at Swarthmore College, as a master's and doctoral student in inorganic and physical chemistry at Cornell University, and as a postdoctoral researcher at Princeton University and the University of Pennsylvania, where one of his advisers was the Nobel Prize-winner Alan G. MacDiarmid. Today, Goldsmith is inspiring Bryn Mawr undergraduates to discover the promise that chemistry holds for society.

Goldsmith's research draws on the diverse knowledge he has acquired in inorganic, physical and synthetic chemistry. "What I'm doing now is an amalgam of everything I've learned to date. I take bits and pieces from the various things I've studied and put them all together into a cohesive, cross-disciplinary research program," he says.

Goldsmith's hydrogen energy research is related to his work on transition-metal complexes - the catalysts for various chemical reactions important to the chemical industry and to biology. His research applies electrochemical and spectroscopic techniques to probe the interaction of transition-metal complexes with electrons, with light and with each other.

Practical Nanotubes

Another of Goldsmith's goals is to develop practical applications that use chemistry to harness some of the basic research currently being carried out in the area of nanoelectronics, he says. He is currently focusing on the vast potential of carbon nanotubes - one of the strongest and most highly conductive materials yet devised. "If you prepare them in the right way, they're the best semiconductors and conductors available today," Goldsmith notes. "The challenge, however, is to harness these properties to make useful, practical devices."

Goldsmith is addressing this problem by designing transition-metal complexes that "add specific functionality to carbon nanotubes without 'messing up' their good properties," he says. This involves chemically synthesizing transition-metal complexes that have ring-shaped molecules, such as naphthalene and anthracene, attached to them. Using these cyclic functional groups, the resulting molecules can be stacked onto carbon surfaces and held together by medium-strength bonds. This interaction is very similar to how layers of benzene rings stack to form soft, flaky graphite, Goldsmith explains.

"I'm trying to make compounds that will stick to graphite and to carbon nanotubes. By noncovalently functionalizing carbon nanotubes with transition-metal complexes, we can prepare the nanotubes to be customized for all sorts of interesting electronic uses," Goldsmith says. In particular, he notes, carbon nanotubes are potentially the next step down in size for computer circuitry. Some research groups are already making transistors from tiny, individual carbon nanotubes that are just one nanometer - one billionth of a meter - in diameter. By comparison, the diameter of a human hair is approximately 100,000 times larger.

Challenging Students

Goldsmith currently has two Bryn Mawr undergraduates assisting in his research, and he hopes to involve more students once his lab is up and running. In his second semester at Bryn Mawr, he is teaching Physical Chemistry and a research-methodology course, after offering General Chemistry and Special Topics in Nanoscience last fall.

"The nanoscience course is useful to a range of science majors since it comprises a set of techniques that are useful in studying problems in many fields beyond chemistry," Goldsmith says. The course examines the future potential as well as the current reality of nanoscience. "In this class, we try to titrate the reality out of the hype. My goal is to introduce students to new ideas, new ways of looking at things and new ways of tackling problems. These skills can be applied to any field of science."

In this way, Goldsmith is teaching students how to approach science from a broader perspective, much like his own research outlook, which draws on a diverse knowledge base to inform specific inquiry.

By Jennifer Fisher Wilson for Bryn Mawr S&T

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