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Quantum-chemical calculations of electronic effects in multivalent interactions

Drugs, viruses and the body’s own messengers usually use multiple interactions with their target structures. They often have a choice of more than one “contact site” to dock to their receptors. (The same holds for the receptors.) Multivalency also plays a central role in the organization of small molecules to form larger units. The SFB 765 investigates changes in the physical, chemical and pharmacological properties of molecules as a result of acquiring more than one binding site. It is hoped that this research will result in more effective drugs and new materials as well as suitable model systems that will advance the study and understanding the fundamentals of multivalency effects.

In the framework of the SFB 765 Project C7: Quantum-chemical calculation of electronic effects in multivalent interactions we are working on the following topics:

  • Quantum-chemical studies on the interaction of pyridine derivatives with gold nanoparticles: from pyridine-gold complexes to adsorption on gold surfaces (collaboration with Prof. Dr. H.-U. Reißig and Prof. Dr. E. Rühl/Dr. C. Graf)

  • Adsorption of monodentate, bidentate and tridentate alkylthiols on Au(111) surface: a DFT study (in collaboration with Prof. Dr. E. Rühl/Dr. C. Graf)
  • Bindings in metallo-supramolecular coordination compounds (in collaboration with Prof. Dr. H.-U. Reißig and Prof. Dr. J. P. Rabe)

Figure:Possible pyridine metal-ion structure on graphene

Whereas traditional chemistry involves the study of molecules consisting of atoms held together by strong covalent bonds, supramolecular chemistry uses molecules as the basic building blocks for the construction of larger aggregates. These are held together by weak interactions, such as hydrogen bonds, electrostatic interactions, van der Waals interactions, or the stacking of aromatic rings. Although these interactions are individually much weaker than the covalent bonds in organic molecules, by employing large numbers of them very robust assemblies of molecules can be formed.

One of the most versatile ways to build such assemblies is to make use of interactions between metal ions (M) and donor groups in organic molecules (ligands, L), as has long been exploited in traditional coordination chemistry. By employing ligands that bridge more than one metal centre it is possible to construct one‐, two‐ or three‐ dimensional architectures, based on M‐L interactions. This is metallo-supramolecular chemistry, a term introduced by Constable in 1994, wherein the metals act as a type of "glue" to hold together assemblies of organic molecules. The magnitude of such M‐L interactions varies from very weak to very strong, depending on the nature of M and L.

  • Nature of interactions in crown-ammonium pseudo-rotaxane complexes (in collaboration with Prof. Dr. C. Schalley and Dr. Marcus Weber)
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This page was last modified on January 26, 2012, at 03:44 PM