Fast Spinning Accelerates Molecular Spectroscopy

CHICAGO, May 13 -- University of Illinois at Chicago chemists have discovered a new approach to speed up a conventional but rather slow way to image molecular structure, yielding results in minutes instead of days or weeks.

Yoshitaka Ishii, assistant professor of chemistry, and graduate students Nalinda Wickramasinghe and Sandra Chimon, reported the findings recently in the Journal of the American Chemical Society.

Their research tool is carbon-13 solid-state nuclear magnetic resonance, used to analyze molecules in nonsoluble, or "solid-state," compounds. Their targets include such important classes of molecules as proteins bound to biomembranes and synthetic polymers.

But the tool is only minimally effective in analyzing compounds containing metals, notably paramagnetic organometallic complexes in solids -- important but often-intractable substances found, for example, in biological activities such as photosynthesis and in some materials science chemical reactions.

Ishii managed to sharpen the resolution of telltale spectral readings of these paramagnetic complexes by modifying a laboratory probe rather whimsically called "very fast magic-angle spinning." That, in turn, has led to some high-resolution one- and two-dimension spectral images of these chemical substances.

"It's quite a simple method, actually. You just spin a sample very fast and get higher sensitivity. But nobody expected one could get the kind of improvement we did," said Ishii. "It's 250 times faster than the conventional method. Some experiments take, in principle, a year the conventional way. With our method, it can be completed in a day and maybe in an hour, with our ongoing efforts. The impossible is made possible with this method."

Ishii hopes this modified method of using carbon-13 nuclear magnetic resonance imaging will open up research opportunities in such fields as nanocomposite materials and pharmaceuticals -- opportunities that were previously too laborious to carry out because of time constraints.

Ishii said he also wants to apply this method to examine the complex formation of beta-amyloid peptides, found in the brain plaques of Alzheimer's disease patients, and their binding to copper.

For more information, visit: www.uic.edu