Synergistic Effect of X-ray Crystallography and Solution NMR on Structural Characterization of Organolithium Complexes

Guang, Jie

Full Metadata

Overview

Year:: 2015
Contributor:: Guang, Jie (creator); Williard, Paul (Director); Basu, Amit (Reader); Seto, Christopher (Reader); Brown University. Chemistry (sponsor)
Genre:: theses
Subject:: organolithium; solution NMR; Organolithium compounds; X-ray crystallography
Extent:: xvi, 135 p.
DOI: https://doi.org/10.7301/Z0NC5ZKV

Files

Description

Abstract:: Structural characterization of organolithium compounds in solution is an important but challenging task. Solution nuclear magnetic resonance (NMR) and X-ray crystallography are two of the most powerful and widely used methods to overcome this challenge. However the correct and reliable interpretation for the NMR spectra of organolithium complexes is difficult, because a) NMR samples contain impurities because organolithium compounds are air-sensitive; b) even pure samples can be mixture as organolithium reagents form various oligomers and mixed aggregates; c) peak assignments in NMR spectra can be ambiguous as different oligomers and aggregates may have very similar structures and present duplicate absorbance. On the other hand, the limitation of X-ray crystallography is also obvious: as a solid-state method, X-ray diffraction (XRD) does not offer structural information for the liquid state. However the combination of NMR and XRD presents a synergistic effect, because NMR helps optimize the preparation conditions of various crystals and X-ray analysis offers trustworthy structural information and unambiguous assignment to partial NMR spectra. This combination becomes the crucial foundation for the interpretation of the NMR data. A variety of systems has been studied by this NMR/XRD integrated protocal including lithium enolates, lithium amide bases and perfluoro Grignard reagents. This thesis incorporates examples that illustrate the application of X-ray crystallography and a variety of multi nuclei (1H, 2H, 6Li, 13C, 19F) NMR techniques including referenced diffusion-ordered NMR spectroscopy (DOSY) to structural analysis.
Notes:: Thesis (Ph.D. -- Brown University (2015)

Content

Access Conditions

Rights: In Copyright
Restrictions on Use: Collection is open for research.

Citation

Guang, Jie, "Synergistic Effect of X-ray Crystallography and Solution NMR on Structural Characterization of Organolithium Complexes" (2015). Chemistry Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.7301/Z0NC5ZKV

Relations

Collection:

Chemistry Theses and Dissertations

Theses and Dissertations for the Chemistry department.
...