Open Access Dissertation
Date of Award
Matthew J. Allen
Macrocyclic complexes have been useful in understanding many systems encountered in biology, along with having widespread use in analytical, pharmaceutical, and synthetic chemistry. My goal was to provide a quantitative experimental and theoretical description of cation-aza-crown and thia-crown ether interactions with alkali metal cations. Infrared multiple photon dissociation (IRMPD) action spectroscopy and energy-resolved collision-induced dissociation (CID) techniques were used in conjunction with theoretical electronic structure calculations to characterize the structures, binding interactions, and stability of cation-aza-crown ether interactions. Quantum chemical calculations at several levels of theory were employed to characterize the structures and stabilities of the isolated cations and aza-crown and thia-crown ethers, as well as noncovalently bound complexes comprised of these species. Quantum chemical calculations were also used to generate linear IR spectra and provide theoretical bond dissociation energy (BDEs) for comparison to IRMPD action spectra and experimentally determined BDEs, respectively. Guided ion beam tandem mass spectrometry techniques were used to characterize the energy dependence of the collision-induced dissociation behavior of these cation-aza-crown ether complexes. The photodissociation experiments were carried out in a 4.7 T Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) coupled to a wavelength tunable free electron laser (FEL). The gas phase trend suggests that binding is determined by electrostatic interactions indicating the charge density of the cation is the major feature controlling binding for the alkali metal cations complex macrocyclic ligand. The gas phase trend also suggests that N donor atoms are more selective for hard metal cations, whereas O donor atoms are slightly more selective for softer metal cations, and S donor atoms bind the alkali metal cation the weakest. Results here suggests that the nitrogen donor atoms macrocycles can selectivity and strongly bind the alkali metal cations in the proper environment similar to oxygen donor atoms macrocycles.
Austin, Calvin A., "Noncovalent Interactions Between Alkali Metal Cation And Aza/thia-Crown Macrocycles: Mass Spectrometric Techniques And Theoretical Studies" (2015). Wayne State University Dissertations. 1304.