DEPARTMENT OF CHEMISTRY
Dr. James R. Durig
Curators’ Professor of Chemistry
Current Research Interests
The research currently being pursued in our laboratory can be classified as both physical chemistry and analytical chemistry. In the physical chemistry area we are pursing spectroscopic studies utilizing infrared, Raman and microwave techniques to determine the conformational stability of a number of small organosilicon or organophosphorous molecules. In particular, we are utilizing low temperature solutions of rare gas molecules such as krypton or xenon to determine the enthalpy for conformational interchange with the results strongly correlated with the enthalpy differences in the gas phase if the molecules have nearly the same molecular size and dipole moments. By utilizing this information and the structural parameters frequently obtained from the microwave spectra along with the asymmetric torsional transitions observed in the far infrared spectra it is possible to determine the anharmonic potential function governing the conformational interchange. Therefore, much of the work on conformational analysis also includes far infrared spectral investigations. Infrared and Raman spectroscopy are techniques that can be used for gases, liquids and solids, so it is possible to determine the conformational stability in all three physical states. We have found in several cases where the more stable conformer found in the gas is not the most stable one found in the liquid.
In addition to the spectroscopic studies, we also carry out ab initio calculations to predict the infrared and Raman spectra including the frequency of the normal modes and their intensities. We also calculate the conformational stability, the structural parameters, depolarization ratio of the Raman bands and the harmonic force constants. These theoretical data are compared to the experimental values when appropriate.
We have been carrying out a series of studies on three-membered rings and monosubstituted allyl compounds to determine their conformational stability and obtain information on the bonding. Bonding in the three-membered rings is frequently compared to those of molecules with carbon-carbon double bonds. Interesting results have been found to date and we are continuing the investigation to determine the effect of electronegativity of the substituent along with steric effects and hybridization in both types of molecules.
We are carrying out vibrational spectroscopic studies on molecules that are environmentally important or of importance in new materials. These studies are for the purposes of identifying decomposition products of chemicals utilized in the environment as well as molecules of biological interest. We are also conducting studies on the absorbance of peat of hydrocarbons and heavy metals. Various types of peat have been investigated for this purpose along with changes in acidity. Material characterizations by GC-FT-IR and Raman techniques are also being pursued.