DOSY External Calibration Curve Molecular Weight Determination as a Valuable Methodology in Characterizing Reactive Intermediates in Solution

DOSY External Calibration Curve Molecular Weight Determination as a Valuable Methodology in Characterizing Reactive Intermediates in Solution

Roman Neufeld

Doctoral thesis

Date of Examination: 2016-03-14

Date of issue: 2016-04-01

Advisor: Stalke, Dietmar Prof. Dr.

Referee: Stalke, Dietmar Prof. Dr.

Referee: Schneider, Sven Prof. Dr.

Persistent Address: http://hdl.handle.net/11858/00-1735-0000-0028-8713-A

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Abstract

English

A new DOSY-ECC-MW-determination methodology is introduced. This method determines molecular weights of unknown solutes in THF-d8 and TOL-d8 solution with exceptional accurately and reliability with a maximum deviation of ±9%. Due to the normalized diffusion coefficients one internal reference is sufficient. This method has the huge advantage that it is unnecessary to introduce multiple references into the same NMR sample. Signal overlapping, analyte-reference interaction problems, wasting chemicals and deuterated solvents can be avoided. The ECC-approach was used to determine the solution structures of e.g. lithium diisopropyl amide (LDA), Na-indenide, Hauser base iPr2NMgCl and Turbo Hauser Bases iPr2NMgCl·LiCl and TMPMgCl·LiCl. The presented organometallic solution structures provide details on reaction conditions which should have a tremendous impact on modified reaction protocols.

Keywords: Diffusion Coefficients; External Calibration Curves; ECC; Synthetically Useful Metal Amides; DOSY; Molecular Weight Determination; Diffusion ordered spectroscopy; Solution Structure; Na-Indenide; Hauser Bases; Turbo Hauser Bases; Lithium Amides; LDA; LiTMP; LiHMDS; iPr2NMgCl•LiCl; iPr2NMgCl; TMPMgCl•LiCl