With this award from the Chemistry Research Instrumentation and Facilities: Multi-user (CRIF:MU) program, Professor Klaus Theopold and colleagues Joseph Fox and Charles Riordan from University of Delaware will acquire a single-crystal X-ray diffractometer equipped with variable temperature capabilities, a CCD detector and a molybdenum source. The award will enhance research training and education at all levels, especially in areas of study such as (a) computationally guided design of catalysts for fluoroolefin polymerization, (b) dioxygen activation with nickel complexes, (c) asymmetric catalysts based on metal-salens, (d) synthesis and structural characterization of lanthanide based silicides and germanides, and (e) use of transition metal catalysis.
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 and will also be used for collaborations with researchers and students at the University of North Carolina-Charlotte, the University of Hawaii, James Madison University, Gettysburg College, Haverford College and Widener University.
The reason why ice floats, butter is greasy, mirrors are shiny and diamonds are hard is because of the atoms that make them up and how these atoms are connected to each other to form structures. Small wonder then, that determining structures is an important part in making new materials and in understanding how these materials behave! The structural form of these compounds usually suggest how these molecules react much in the same way that the shape of a key determines which lock it could open. The grant allowed us to purchase a device known as a diffractometer that allows us to shoot X-rays into a crystal sample, and carefully measure the pattern that results from the crystal-scattered X-rays. The pattern can then be used to determine the structure of the substance composing the crystal. Many of the new structures discovered as a result of this grant contain a metal atom partially shielded by an organic, non-metallic group that serves to tune the activity of the whole molecule. By judicious choice of the metal and non-metal parts, the resulting compounds have been shown to be useful in diverse fields such as renewable energy, industrial waste treatment, and novel material development. Other structures have elucidated key steps in chemical transformations, or have modeled transformations that occur in living organisms. In some cases structures can have handedness in a similar way that left hands are different from right hands. In the 1960’s a drug called thalidomide was introduced for alleviation of morning sickness in pregnant women. The active compound can exist and was made in both handedness. Unfortunately it was later found out that one of the two possible handed forms caused birth defects. To be able to distinguish handedness using most diffractometers, compounds are normally required to contain sodium or larger atoms. The diffractometer purchased with this grant can determine handedness in the absence of atoms larger than sodium. Therefore something like thalidomide, which only contains carbon, hydrogen, oxygen and nitrogen, could be analyzed directly without modification. Modification of the compound under study is often not ideal since the modification in itself might be skew results. In some cases the nature of the compound does not allow for easy modification in any case. Some of the structures we have determined confirmed new ways of selectively making one form despite when both handedness are theoretically possible. In other cases, wherein the molecule can express handedness in more than one part, the structures obtained gave us insight into what possible combinations are favored. We communicate our research progress by submitting and publishing in peer-reviewed journals. We are please to report that 21 papers have been published to date with findings resulting from this grant. We are equally pleased that these papers in turn have inspired 39 other research papers that have cited our work. This grant allowed student research that resulted in eight new scientists graduated with doctorate degrees and three with masters degrees. This grant also allowed the continued operation of the X-ray Crystallography Laboratory that conducts extension services including activities to inspire budding young scientists such as the Take Our Daughters and Sons to Work Day, Delaware Decision Days, and visits from Wilmington Friends School. Most importantly we believe that this grant afforded us to explore and contribute in the field of chemistry and the general body of human thought.
