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M. Czakler, Ch. Artner, U. Schubert:
"Synthesis of New Titanium Oxo Clusters Using Phophonic Acid Derivatives";
Poster: 4^th EuCheMS Chemistry Congress, Prague, Czech Republic; 2012-08-26 - 2012-08-30; in: "4^th EuCheMS Chemistry Congress - Final Program", (2012), P-207.

Clusters are interesting intermediates between molecules and nanoparticles. Unlike nanoparticles they are formed as defined and soluble compounds, the structure of which can be determined exactly by single crystal XRD and NMR. A versatile route to metal oxo clusters are reactions of metal alkoxides with carboxylic acids. The metal alkoxides are partly hydrolysed by water produced in situ, through esterification of the acid. Controlled condensation is thus achieved, and well defined clusters are formed, which are stabilized by the carboxylate ligand sphere.
New oxo clusters were prepared by varying the carboxylic acids and using mixtures of different carboxylic acids. Furthermore, using phosphonate ligands for the clusters, new highly interesting compounds were synthesised. By employing easily hydrolysed phosphonic acids esters, namely trimethylsilyl esters, instead of phosphonic acids themselves, the reaction is convenient and the results are better reproducible. A new cluster, the first titanium oxo cluster with functionalized phosphonate ligands, was thus formed. Its structure consists of six titanium atoms and two oxo bridges. Six phosphonates are bound to three titanium atoms each, opening two interconnected tetrahedrons. Interestingly, the cluster has an overall rod-like shape, with only alkoxides ligands on both tips.

Cluster compounds; Titanium

Project Head Ulrich Schubert:
Anisotrope Funktionalisierung von Clustern