Institute of Functional Interfaces

Conformational Adaption in Supramolecular Assembly on Surfaces

  • chair:

    Klappenberger, F. / Caňas-Ventura, M. E. / Clair, S. / Pons, S. / Schlickum, U. / Qu, Z.-R. / Brune, H. / Kern, K. / Strunskus, T. / Wöll, Ch. / Comisso, A. / De Vita, A. / Ruben, M. / Barth, J. V. (2007)

  • place: ChemPhysChem 8 (2007), 1782-1786

  • Date: 2007
  • Klappenberger, F. / Caňas-Ventura, M. E. / Clair, S. / Pons, S. / Schlickum, U. / Qu, Z.-R. / Brune, H. / Kern, K. / Strunskus, T. / Wöll, Ch. / Comisso, A. / De Vita, A. / Ruben, M. / Barth, J. V. (2007): "Conformational Adaption in Supramolecular Assembly on Surfaces". In: ChemPhysChem 8 (2007), 1782-1786

Abstract

Supramolecular chemistry provides an original approach to nanoscience and nanotechnology by its intrinsically molecularlevel control of self-assembly processes. The spontaneous but controlled generation of complex supramolecular entities from suitably designed molecular components opens the way to the efficient—because extremely parallel—bottom-up construction of supramolecular architectures, with specific functionalities emerging at each hierarchic step of complexity.

Among the underlying noncovalent interactions, hydrogen bonding has been shown to be particularly useful for structural control. For two-dimensional (2D) supramolecular engineering, the self-assembly processes are conducted at surfaces. The primary advantages of this approach are the unprecedented direct access to structural information at the atomic level by employing scanning probe techniques, notably scanning tunneling microscopy (STM), and the possibility to realize specific low-dimensional molecular structures that can eventually be integrated into nanostructured environments.

In most systems investigated to date, the transcription to 2D of hydrogen-bonding motifs identified in 3D systems was achieved by employing planar molecular building blocks, (socalled tectons). These adsorb in a flat geometry on surfaces, thus favoring lateral linkages between functional endgroups. In this case, the necessary balance between adsorbate–substrate and lateral intermolecular interactions can be tuned by appropriately selecting the symmetry and chemical reactivity of the substrate.

It is, however, much harder to control tectons exhibiting conformational flexibility, although such species qualify for the self-assembly of particularly elaborate nanostructures. Moreover, the conformational design of single molecules and molecular layers is a crucial ingredient to achieve a targeted set of chemical and physical properties, for example, the realization of single-molecule switches, the control of chiral recognition, or efficient heterogenous catalysis.

To obtain complete control over the assembly behavior of complex molecular species at surfaces, it is thus mandatory to understand the interplay of conformation and supramolecular organization.


 

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