|Title:||Ligand exchange reactions of transition metal oxo clusters and their application for the synthesis of inorganic-organic hybrid materials||Other Titles:||Ligandenaustauschreaktionen an Übergangsmetall Oxo Clustern und ihre Anwendung in der Synthese von organisch-anorganischen Hybridmaterialien||Language:||English||Authors:||Kreutzer, Johannes||Qualification level:||Doctoral||Advisor:||Schubert, Ulrich||Issue Date:||2015||Number of Pages:||118||Qualification level:||Doctoral||Abstract:||
Ligand exchange reactions of transition metal oxo clusters and the impact of modification of the ligand sphere of the clusters on properties of the hybrid materials was investigated. Ligand binding energies of the ligands were calculated by means of DFT calculations. Different basis sets and functionals were evaluated with respect to a sufficiently accurate description of the geometry and the vibrational modes of the cluster Zr4O2(OMc)12 (OMc=methacrylate). Ligand binding energies of the methacrylate ligands with respect to different positions on the cluster and to electronic effects of different substituents on the ligands were also investigated. The methacrylate ligands of Zr4O2(OMc)12 were completely exchanged with pivalic acid to verify that exchange reactions with carboxylic acids on Zr4O2(OMc)12 proceed under retention of the cluster core. Ligand exchange with different sterically demanding ligands was probed and the steric influence on the equilibrium reaction investigated. Scrambling reactions between clusters with the same cluster core but different ligands were investigated by two-dimensional NMR spectroscopy and are a second preparative route to mixed-ligand clusters. The question of site-selective ligand exchange was investigated by exchange of chelating carboxylate ligands with acetylacetonate. However, the stability of the cluster core seems to be of uttermost importance in this reaction. Besides successful site-selective ligand exchange, rearrangement of clusters and degradation was also observed. The impact of ligand exchange reactions on properties of hybrid materials was investigated. Furthermore, bifunctional clusters were synthesized by ligand exchange reactions and used in STED lithography experiments to obtain reactive nanostructures.
|Keywords:||Cluster; Übergangsmetall; Ligandenaustausch; Hybridmaterialien
Cluster; transition metal; ligand exchange; hybrid materials
|Library ID:||AC12397072||Organisation:||E165 - Institut für Materialchemie||Publication Type:||Thesis
|Appears in Collections:||Thesis|
Files in this item:
checked on Jul 23, 2021
checked on Jul 23, 2021
Items in reposiTUm are protected by copyright, with all rights reserved, unless otherwise indicated.