Where: Bldg 9, Classroom 4223
Description
Supramolecular chemistry holds unique prospects for the fabrication of novel functional materials. Molecularly precisely defined, nanometer-sized subunits which may already be rather complex self-assemble to form even more complex structures which exhibit functionalities not provided by the individual building blocks. In this presentation it will be made evident that supramolecular chemistry has in particular a huge potential with regard to the functionalization of surfaces and interfaces. We will demonstrate that this potential goes well beyond surface-templated assembly of two dimensional networks of organic molecules (ligands) interacting through hydrogen bonds or ionic interactions [1] and allows to construct three-dimensional, crystalline, perfectly ordered and oriented multilayers. The basis for the approach described here are highly porous metal-organic frameworks (MOFs), a novel class of porous bulk compounds with more than 20.000 different reported structures. In order to apply them for interface functionalization, we have developed a liquid phase epitaxy process, which allows growing MOFs on modified substrates using a layer-by-layer procedure [2]. The availability of porous frameworks rigidly anchored to solid surfaces, SURMOFs, opens the prospect of adding additional functionality to these ultrathin surface coatings [4] by placing nanoobjects inside the pores within the MOFs, e.g. metal clusters or dye molecules [3]. We will demonstrate the potential of this approach by loading the three-dimensional porous scaffolds, or “designer solids”, with metal-containing molecules such as ferrocene and then characterizing their properties using electrochemistry [5]. We will close the presentation by introducing SURCOFs, which are made from SURMOFs via a cross-linking process involving secondary linkers. The subsequent removal of the metal ions using complexation agents [6] converts the MOF held together by ionic bonds to a COF. The potential of these SURCOFs (surface-bound covalent organic frameworks) for life-science applications will be demonstrated.
Christof Wöll
Christof Wöll, Professor Dr., has accepted in June 2009 an offer to become a W3 professor at the University of Karlsruhe (TH). At the same time he has been appointed director of the Institute of Functional Interfaces (IFG) of Karlsruhe Institute of Technology (KIT) (successor of Rolf Nüesch). Wöll studied physics at the University of Göttingen and was awarded a PhD in 1987 for work carried out under the supervision of Peter Toennies at the Max-Planck-Institut für Strömungsforschung, Göttingen. From 1988 to 1989, he worked as a research associate at the IBM research laboratories, San Jose, CA/USA. Then, he hold a position equivalent to Assistant Professor at the Chair of Applied Physical Chemistry of the University of Heidelberg (Head of chair: Prof. Michael Grunze) for five years. After his habilitation, Wöll was granted a Heisenberg scholarship by the German Science Foundation (DFG) in 1994. He headed the Photoelectron Spectroscopy Group at the Chair of Applied Physical Chemistry of the University of Heidelberg and established a Molecular Beam Scattering Group at the Max-Planck-Institut für Strömungsforschung, Göttingen. In 1997, he accepted an offer made by the University of Bochum to take over the chair for Physical Chemistry. In Bochum he founded the collaborative research center SFB558 “Metal-substrate Interactions in Heterogeneous Catalysis” in 2000.
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