Ligand Protected Clusters

In recent years various wet-chemical methods have been developed to synthesize clusters comprising different chemical elements [1]. Such synthetic methods prove advantageous for future application because they are cheap and considerably easy to perform. However, to avoid agglomeration of the particles, the clusters have to be stabilized, which is generally done by protection with a ligand shell. These ligands are anchored to the cluster core and may also influence the activity of the clusters for certain reaction. Hence, by a clever choice of the right ligand molecule, either the reactivity [2] or the chemoselectivity [3] and the stereoselectivity [4] of the catalyst can additionally be tuned.

Our aim in this project, which is performed in cooperation with Mirza Cokoja from the Inorganic Chemistry, is twofold. First, our goal is to tune the size of the particle by wet-chemical methods and to identify size dependent properties such as the reactivity and selectivity. Our studies in the ultra-high vacuum on size selected clusters will serve as a benchmark for the desired sizes and will allow for a detail assignment of the effects that govern the reactivity of the clusters.

Our second goal for this project is to study the role of the ligand and its influence on the cluster. By the application of different wet-chemical methods and a thorough characterization of the functionalized clusters it is possible to isolate distinct parameters and to study their implication on the catalytic properties separately. 

Only by a comprehensive understanding of the role of both components – the cluster and the ligand – a rational design of such catalysts will eventually become possible.