Molecular Spectroscopy Lab Uses NMR to Characterize Polymers
Homegrown Spectral Database Aids in Identification

When Peter Rinaldi arrived at the University of Akron 11 years ago, he had no idea that he would put together a major NMR facility. "When I arrived," he said, "there were a couple of instruments." Now the Molecular Spectroscopy Lab he directs has a 750 MHz NMR from Varian Instruments (Palo Alto, CA) and a large number of lower field instruments.

Initially funded by the State of Ohio and through a challenge grant from the Kresge Foundation, the lab has emerged as a regional facility, serving both the academic community and the industrial base in the area. According to Rinaldi, who received his Ph.D. from the University of Illinois, Urbana-Champaign and served as an assistant professor at Case Western University and with Varian before coming to Akron in 1987, in addition the Akron faculty, about 30 to 40 scientists from other academic institutions and 30 to 40 scientists from industrial labs make use of facility. Nearly all the major industrial players in the area including Goodyear, B.F. Goodrich, Bridgestone, and Firestone have had a relationship with the lab. "Companies come here because we can do things that can't be done anywhere else," Rinaldi said. "Also, they want to support the university."

Although NMR is often used as a tool to characterize proteins, the focus of the Molecular Spectroscopy Lab at Akron is on the characterization of polymers and plastics as well. That is not surprising for a university that has a college of polymer science and polymer engineering. Rinaldi's research team develops new NMR techniques and the application of computers, networks, and digital processing in NMR spectroscopy. Currently, the team is exploring new methods to determine internuclear distances in large molecules such as polymers.. They use techniques that exploit what is called Nuclear Overhauser Enhancements (NOE) phenomena within a context of 2D and 3D NMR experiments. They apply these methods to study problems associated with metal ion and substration binding to biomolecules.

In another line of research, Rinaldi and his team use state-of-the-art NMR instruments to perform triple resonance experiments. When combined with isotopic labeling, the experiments allow the scientists to observe NMR spectra of specific sites of complex molecules without interference resonances from the rest of the molecule. They use the techniques to monitor reactions at modified sites on polymers in an effort to better understand the structure, conformation and reactivity of materials.

The 2D and 3D NMR experiments generate huge data sets, Rinaldi noted. The lab has a network with primarily Windows NT, Windows 95, Macintosh computers, and Sun SPARCstation. There are also some Silicon Graphics workstations for molecular modeling and molecular simulation. It also has a copy of the brookhaven protein database. Including instruments and shared peripheral devices, there are more than 200 nodes on the lab.

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Recent, the lab has turned to software called ACD/NMR Manager from Advanced Chemistry Development (Toronto, ONT) to create a database to manage the NMR spectral information. "We do a lot of polymer analysis," Rinaldi noted. And while there are small compilations of NMR resonances in the published literature, Rinaldi and his group are working to build a large database, which also includes the NMR spectral characterizations of large molecules. NMR/Manager can take raw NMR data directly from the spectrometer, from any of the key spectrometer formats, and process it using tools for manipulation and annotation of the spectra prior to building spectral databases. It has the ability to store, search and display spectral libraries with or without assignments, for any nucleus, for polymers or small molecules, high resolution or solid state NMR. ACD claims it is the first complete package to take data from the spectrometer and provide desktop or centralized NMR spectral libraries.

"This will make it easier to detect a shift in resonances," Rinaldi says. "You could search through books for weeks and still miss what you are looking for. The computer doesn't miss anything."

Rinaldi is also evaluating ACD's laboratory information management systems for spectral information (SLIMS) ACD/SLIMS is a web-based application tool kit that offers sample tracking statistics and analysis, structure management and range of drawing and display Java applets and download capabilities for spreadsheets, reports of analysis, chemical structure and spectra in a wide array of formats.

Rinaldi is intrigued because the system is web-based and the administrator can define appropriate security levels easily. "Because it is Web-Base with Java, anybody you want can have access," said Rinaldi. Many different communities of user take advantage of the facility. To a limited extend, personnel will E-mail or ftp results to scientists off campus.

But SLIMS could solve a complicated communications issue. "We can grant an account and a password and all they need is a Web Browser," Rinaldi noted.

"We are always seeking novel ways to exploit computer hardware and software in NMR experimentation." Rinaldi said.

Elliot King

Scientific Computing & Automation

(W-14, June 1998)