High Resolution Spectroscopy of Chirality Recognition and Solvation of Prototype Chiral Molecular Systems Open Access
- Other title
- Type of item
- Degree grantor
University of Alberta
- Author or creator
- Supervisor and department
Xu, Yunjie (Chemistry)
- Examining committee member and department
Hanna, Gabriel (Chemistry)
Serpe, J. Michael (Chemistry)
Mar, Arthur (Chemistry)
Novick, E. Stewart (Wesleyan University)
Lucy, A. Charles (Chemistry)
Department of Chemistry
- Date accepted
- Graduation date
Doctor of Philosophy
- Degree level
The chirality recognition, chirality induction, chirality amplification, chirality synchronization and solvation of prototypic chiral molecular systems were studied using chirped pulse and cavity based Fourier transform microwave spectroscopy with the aid of high level ab initio calculations. The spectroscopic and theoretical results were utilized to derive detailed information about the structures and dynamics of the molecular systems under the conditions of supersonic jet expansion. The various factors contributing to the chirality recognition process in general were explored in the studies.
The chirality recognition study between two permanently chiral molecules glycidol and propylene oxide demonstrates the key roles that the stability and deformation energies of the monomers and their intermolecular interaction energy play in determining the relative stability of the binary conformations. The amplification of chirality in a transient chiral molecule, 2,2,2-trifluoroethanol induced by a permanent chiral molecule propylene oxide was observed. Four out of eight predicted binary conformers were detected, while the other four were shown to relax to these four representative geometries under the jet expansion environment. The study further revealed that the conformational stability in the binary adducts is dominated by intermolecular interaction since the monomeric subunits utilized in each binary adduct are of the same energy. The chirality self-recognition study in the dimer of 2,2,2-trifluoroethanol reports the first experimental detection of the elusive heterochiral dimer. This detection unequivocally establishes that tunneling between the gauche forms of 2,2,2-trifluoroethanol cannot be responsible for the strong chirality synchronization observed. The result highlights the advantages of using high resolution spectroscopy in comparison to low resolution spectroscopy, in providing detailed and important structural and dynamical information about the molecular recognition process at the microscopic level.
The first step of the solvation process of methyl lactate, a multifunctional chiral molecule, by ammonia was investigated. The nuclear quadrupole hyperfine structures observed provide in-depth information about the charge transfer between a chiral molecule to an achiral molecule due to complex formation. A step wise solvation study of methyl lactate by water showcases the capability of high resolution spectroscopy to differentiate minute conformational variation. It also provides a possible link between the unique orientation of the free hydroxyl groups in these small clusters and the previously observed chirality transfer features of water in aqueous solution of methyl lactate. The solvation study of 2,2,2-trifluoroethanol with water reveals a strong preference for the insertion versus addition binding topology in the solvation process. Similar preferences were observed in studies of complexes of methyl lactate with water and with ammonia.
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
- Citation for previous publication
J. Thomas, F. X. Sunahori, N. Borho, and Y. Xu, “Chirality recognition in the glycidol•••propylene oxide complex: a rotational spectroscopic study," Chem. Eur. J. 2011, 17, 4582 – 4587.J. Thomas, W. Jäger and Y. Xu, "Chirality induction and amplification in the 2,2,2-Trifluoroethanol ••propylene oxide adduct,"Angew. Chem. Int. Ed. DOI: 10.1002/anie.201403838; Angew. Chem. DOI: 10.1002/ ange. 201403838.J. Thomas and Y. Xu, "Chirality synchronization in trifluoroethanol dimer revisited: the missing heterochiral dimer" J. Phys. Chem. Lett. 2014, 5, 1850-1855.J. Thomas, O. Sukhorukov, W. Jäger and Y. Xu, "Chirped pulse and cavity based FTMW spectra of the methyl lactate- ammonia adduct," in Angew. Chem. Int. Ed., 2013, 52, 4402–4405 .J. Thomas, O. Sukhorukov, W. Jäger and Y. Xu, "Direct spectroscopic detection of unique free OH orientation in methyl lactate--(water)1,2 clusters: hydration of a chiral hydroxy ester," Angew. Chem. Int. Ed. 2014, 53, 1156–1159; Angew. Chem. 2014, 126, 1175–1178.J. Thomas and Y. Xu, "Structure and tunneling dynamics in a model system of peptide co-solvents: rotational spectroscopy of the 2,2,2-trifluoroethanol••water complex", J. Chem. Phys. 2014, (Accepted).
- Date Uploaded
- Date Modified
- Audit Status
- Audits have not yet been run on this file.
File format: pdf (PDF/A)
Mime type: application/pdf
File size: 7740802
Last modified: 2016:06:24 17:54:53-06:00
Original checksum: ae20c42790c0252d958df45e25ce6d67
Activity of users you follow