Rotational Spectroscopy and Gas Phase Structures of Hydrogen Bonded Dimers, Organometallic Complexes and Other Molecules

Abstract

This dissertation focuses on the structural investigation of gas phase organometallic complexes, hydrogen-bonded dimers and other organic molecules through the use of pulsed-beam Fourier transform microwave spectroscopy technique and high-level computational methods. High-resolution microwave spectra and important structural parameters such as rotational constants and quadrupole coupling constants were measured and obtained for organometallic molecules ferrocenecarboxylic acid and methylmanganese pentacarbonyl, organic molecules 1-chloroborepin, phenylpropiolic acid and 2-aminopyridine, as well as hydrogen bonded dimer formamidinium formate. These studies have produced new important information for these molecules in regard to their gas phase structures, conformational behaviors, electronic charge distributions, chemical bonding and reactivity. Theoretical computations using Density Functional Theory (DFT) and ab initio methods were carried out to obtain optimized electronic structures of the molecules studied. The theoretical structures and parameters derived facilitated the scanning and assignment of rotational transitions. In addition, the comparisons between theoretically computed and experimentally determined structural parameters provide insights for structural determination of the molecules and other important molecular properties.