Conformational and Structural Determinations of Substituted Four and Five Membered Rings by Infrared, Raman, and Microwave Spectral Studies

Abstract

Studies of the structure and conformational stabilities of molecules have become increasingly important due in part to advances in the fields of biochemistry and nanochemistry. Specifically the conformation of organoamines is currently at work in every human alive with this arising from the amino acids in proteins and the substituted bases in DNA and RNA. The importance of conformational stability is further demonstrated in biological systems by enzyme binding where the conformational changes of the protein can change the binding site either enhancing or deactivating the enzyme. These systems however tend to have relatively large molecules with many conformers. Thus in this work we explore the use of multiple spectroscopies to stuy four and five membered rings and amines. Infrared, far-infrared, and Raman spectroscopy to of vapor, liquid, solid, and rare gas solutions to determine vibrational assignments, conformational stabilities, and even some structural parameters. We combine this vibrational approach with ab initio calculations and microwave spectroscopy for greatly improved conformational and structural studies. Also explored are new methodologies of variable temperature Raman spectra of rare gas solutions to improve conformational stuies of polar compounds or compounds with four or more conformers. Additionally chirped-pulse FT microwave spectroscopy has been applied to structural problems to greatly improve the structural parameters.