Klassifizierung polarer Metall-Kohlenstoff-Bindungen in hauptgruppenmetallorganischen Verbindungen mittels experimenteller Elektronendichteanalyse

Classification of polar metal-carbon bonds in main group organometallic compounds with experimental electron density analysis

by Annika Münch
Doctoral thesis
Date of Examination:2020-07-07
Date of issue:2020-10-20
Advisor:Prof. Dr. Dietmar Stalke
Referee:Prof. Dr. Dietmar Stalke
Referee:Prof. Dr. Thomas Waitz
Referee:Prof. Dr. Manuel Alcarazo
Referee:Prof. Dr. Burkhard Geil
Referee:Prof. Dr. Thomas Zeuch
Referee:Dr. Nathalie Jun.-prof. Kunkel
Persistent Address: http://dx.doi.org/10.53846/goediss-8169

 

 

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Abstract

English

In general, organometallic compounds are characterized by their metal-carbon bond. This is characterized by its polar nature. Examples of this class of compounds are Grignard reagents and organolithium compounds such as n-butyllithium (nBuLi). They are widely used in industry as stoichiometric reagents; for example, they are useful both stoichiometrically and catalytically for many polymerization reactions. Almost all syntheses of polymer chemistry from alkene-containing compounds are carried out using organometallic catalysts. The polyethylene (PE) and polypropylene (PP) used worldwide are produced both from the heterogeneous Ziegler-Natta catalysis and homogeneously, for example via metallocene-controlled catalysis. Alkyllithium (RLi) and alkylaluminum compounds (R3Al) are characteristic examples of this class of compounds, as they reflect its properties. They are used as a highly basic nucleophilic and strongly reducing reagent. So far, many variables have been examined when examining these reagents, but the influence and degree of polarity have not yet been considered. The method of high-resolution X-ray structure analysis is suitable for examining this variable. As part of this dissertation, the topological analysis of the experimentally obtained electron density with the aid of the QTAIM developed by R. F. W. BADER was used to elucidate the bonding situation of the main group organometallic compounds and the imido analogue of sulfuric acid. The electron density was obtained using the HANSEN-COPPENS formalism for description by means of a suitable multipole model against high-resolution X-ray diffraction data. Quantum chemical calculations were carried out as a supporting method. In addition to the elucidation of the polar metal carbon or sulfur nitrogen bond, various data processing methods and models to describe the ED could be tested due to the excellent quality of the X-ray diffraction data. The focus of this study was the description of the hydrogen oscillation using different methods.
Keywords: Charge Density Analysis; Alkyllithium; Crystal structure
 
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