Wednesday, May 13, 1998
Science Files
Stoddart builds molecular chains
One of the foremost organic chemists in the world, J. Fraser
Stoddart gets to play with microscopic rings for a living.
Stoddart, in his lab, examines the spontaneous ways molecules in
nature come together to make bigger structures.
"You have to go to what I call the molecular toolbox and pick up
bits and pieces from the chemical knowledge which you think will
work, and create a rather sophisticated structure which can
function in ways that can be harnessed by the medical science or
material science," said Stoddart.
Stoddart holder of UCLA’s Saul Winstein Chair in organic
chemistry.
By building functional groups in strategic positions, the
"sticky" molecules interact with each other to form structures like
catenanes – tiny interlocking ring-shaped molecules.
"They are not loose rings – they are rings oriented with respect
to each other.
"There is a lot of cross-talk between them and lot of
information being exchanged," he said.
The chemical groups can therefore recognize each other and
self-assemble in solution, thus forming ring structures which hold
promise for the development of new materials.
Stoddart’s work will be published in a science journal within
the next week.
Carter models molecular activity
For physical chemists, analyzing single molecules in the lab is
extremely difficult to do.
Computer models, if available, can be used to simulate certain
molecular behaviors that cannot be easily created in the lab.
Using quantum mechanics as a theoretical basis, Emily Carter,
professor of chemistry and biochemistry, has developed new computer
models to simulate specific behaviors of single molecules.
"We are able to analyze very short time-scales, observing
molecular vibrations and transition states that occur in seconds,
all the way to characterizing interactions for minutes," said
Carter, who leads the research team.
Among their many current projects, the researchers are
developing computer models to search for catalysts able to reduce
chemical warfare agents into nontoxic products for the U.S.
Army.
Scientists are also attempting to develop a clean-burning
substitute for diesel fuel by determining how dimethyl ether, a
gasoline additive, interacts with oxygen during combustion. This
research, funded by the Ford Motor Company, will be beneficial in
Europe, where unleaded gasoline is very expensive.
By Matt Grace and Chauntelle Tibbals, Daily Bruin
Contributors
Courtesy of J. Fraser Stoddart
Professor J. Fraser Stoddart