[Back]

V. Truttmann, N. Barrabés-Rabanal, T. Bürgi, G. Rupprechter:
"Ligand Exchange Reactions on Au-Nanoclusters";
Poster: 17th Austrian Chemistry Days 2017 - Joint Meeting of the Swiss & Austrian Chemical Societies, Salzburg; 09-25-2017 - 09-28-2017; in: "17th Austrian Chemistry Days 2017", (2017).

Ligand protected Au-nanoclusters are promising candidates for a broad field of application, including catalysis. They are very stable and exhibit size dependant physical-chemical properties, which are related to the number and nature of the metal atom composition, as well as the nature of the protecting ligand. Moreover, these properties can be tuned by exchanging the surface ligands of the cluster (in a ligand exchange reaction), while a defined core size is maintained [1,2]. For catalytic applications, the cluster is usually immobilized on an oxide substrate (e.g. CeO2, Al2O3) [3]. However, the nature of the interactions between the cluster and its support and the effect on its properties are still not resolved.
We therefore successfully designed a system to study those interactions. Clusters with different types of ligands (phosphines and thiols) were used, as those have great influence on the cluster´s properties and structure [4]. The phosphine ligands were replaced with thiols in ligand exchange reactions, which were monitored in situ by UV-Vis and ATR spectroscopy. Because of the different chemical nature of the ligands (S-; P-), it is possible to distinguish between the ligands interacting with the support and the ligands available for the exchange reaction. Moreover, it also allows us to get an idea of the bonding motive between ligand and oxide substrate.
Due to the understanding of these interactions, as well as the possibility of post-functionalization by ligand exchange, a broad number of catalysts with specific properties can be produced. In addition, reactions with immobilized clusters and chiral ligands lead to the creation of a new type of enantioselective heterogenous catalysts.
____
[1] A. Sels, N. Barrabés, S. Knoppe and T. Bürgi. Nanoscale 2016, 8, 11130-11135
[2] A. Sels, G. Salassa, S. Pollitt, C. Guglieri, G. Rupprechter, N. Barrabés and T. Bürgi. J. Phys.
Chem. C 2017, in press
[3] B. Zhang, S. Kaziz, H. Li, M. G. Hevia, D. Wodka, C. Mazet, T. Bürgi and N. Barrabés. J. Phys.
Chem. C 2015, 119, 11193-11199.
[4] L. C. McKenzie, T. O. Zaikova and J. E. Hutchison. J. Am. Chem. Soc. 2014, 136, 13426-13435.

http://publik.tuwien.ac.at/files/publik_267219.jpg