With this award from the Major Research Instrumentation (MRI) Program, Professor Martin Minelli from Grinnell College and colleagues Charles Cunningham, T. Andrew Mobley and Stephen Sieck will acquire a benchtop X-ray diffractometer. The proposal is aimed at enhancing research training and education at all levels, especially structure studies in areas such as (a) molybdenum coordination complexes, (b) bimetallic organometallic compounds, (c) organic nitrogen (nitrone) compounds, and (d) intermetallic compounds.
An X-ray diffractometer allows accurate and precise measurements of the full three dimensional structure of a molecule, including bond distances and angles, and provides accurate information about the spatial arrangement of a molecule relative to neighboring molecules. The studies described here will impact a number of areas, including organic and inorganic chemistry, materials chemistry and biochemistry. This instrument will be an integral part of teaching as well as research in the chemistry and physics departments.
The purchase of the Bruker X2S diffractometer, funded by the NSF-MRI grant number 1126521, gave the undergraduate students and faculty at Grinnell College the opportunity to solve crystal structures. In the sciences at Grinnell College we have several chemists and one physicist whose research strives to synthesize new compounds. To determine the structure of a new compound, pure crystals have to be grown. In the diffractometer, the crystal interacts with the X-rays and produces an electron density map that can be used to determine the location of the atoms in the new compound. Ideally, the Bruker X2S will determine the structure automatically. Many times, though, this is not the case and the structure needs to be determined manually. During each of the past three years, Dr. Ilia Guzei, the crystallographer from the University of Wisconsin-Madison, has taught a two-week short course at Grinnell College, where he introduced students and faculty to the field of X-ray crystallography and also taught us to solve the structures of crystals that the diffractometer does not solve automatically. The diffractometer at Grinnell College has allowed the research groups of Profs. Cunningham Mobley and Minelli to determine the structures of their metal complexes directly at Grinnell rather than sending them to a different institution. X-ray crystallography has added a new dimension to the research of Profs. Leggans and Sieck who study organic compounds that can possibly serve as precursors for medicinal drugs. The diffractometer has been incorporated in several courses at Grinnell College, inorganic and analytical chemistry, advanced inorganic chemistry, advanced organic chemistry, modern physics and solid state physics. Colleagues at Central College in Pella, Iowa, and a colleague in the College of Pharmacy and Health Science at Drake University in Des Moines, Iowa, also have access to the diffractometer. Overall, the diffractometer has given the students at Grinnell College access to a new physical method that broadens their understanding of chemistry and expands their research capabilities.