[Zurück]

J. Kreutzer, U. Schubert:
"DFT study towards the electronic structure of transition metal oxo clusters";
Poster: International Symposium on Small Particles and Inorganic Clusters XVI, Katholike Universiteit Leuven, Leuven/Belgien; 08.07.2012 - 13.07.2012; in: "ISSPIC XVI - Program & Abstracts", (2012), ISBN: 9789461650559; S. A64.

Transition metal-oxo clusters find increasing interest in material science as nanosized building blocks, especially for inorganic-organic hybrid materials. When polymerizable ligands are attached to the cluster surface, the inorganic building blocks can be incorporated in polymers by covalent bonding. A great number of transition metal-oxo clusters with polymerizable ligands has been synthesized and used to obtain polymers with tailored properties.Most of the clusters used as co-monomers in polymerization reactions show a high number of uniform polymerizable groups on their surface, resulting in highly crosslinked polymers. Anisotropically functionalized transition metal-oxo clusters comprising more than one functional group on the surface with a spacially controlled arrangement could lead to less crosslinked polymers and could widen the applicability of such species.One way to introduce different groups makes use of the ligand dynamics on the cluster surface. Hereby coordinated carboxylate ligands are postsynthetically exchanged by other ligands with different functionalities. For an effective planning of the exchange process knowledge about the geometry, bond strength, electronic structure and ligand dynamics is necessary. OFT is a reliable method for investigating geometrical and electronic structure in small and medium sized Systems. Different functionals and basis sets were empolyed to optimize experimental XRD structures and to explore the electronic structure of Zr, Ti and Hf oxo clusters. The ability of different functionals to predict the bond energy and results from MP2 benchmark calculations will be presented. Additionally the bonding characteristics of such Systems will be discussed on the basis of NBO analysis. Furthermore slteselective effects will be discussed in terms of chemical reactivity theory.

Projektleitung Ulrich Schubert:
Anisotrope Funktionalisierung von Clustern