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O: Oberflächenphysik
O 36: Postersitzung (Elektronische Struktur, Grenzfl
äche fest-flüssig, Halbleiteroberfl
ächen und -grenzfl
ächen, Nanostrukturen, Oberfl
ächenreaktionen, Teilchen und Cluster, Struktur und Dynamik reiner Oberfl
ächen)
O 36.38: Poster
Montag, 7. März 2005, 15:00–18:00, Poster TU F
Two-dimensional supramolecular coordination networks at a metal surface — •Sebastian Stepanow1, Alexandre Dmitriev1, Magalí Lingenfelder1, Hannes Spillmann1, Franck Vidal1, Nian Lin1, Johannes V. Barth2, and Klaus Kern1,2 — 1Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany. — 2Institut de Physique des Nanostructures, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
The self-assembly of iron coordinated two-dimensional supramolecular networks at a Cu(100) surface has been investigated by high-resolution scanning tunnelling microscopy under ultra-high vacuum conditions. As organic linkers we applied rod-like symmetric and asymmetric molecules with carboxylate and pyridyl endgroups. Upon annealing the iron-molecule mixture two-dimensional network structures with diiron coordination centers evolve. The iron pairs are bridged by two equatorial carboxylate groups and coordinated by two or four carboxylate oxygen atoms or two pyridyl nitrogen atoms depending on the axial linker. The orientation of the network and alignment of the diiron unit depends on the functional groups of the molecule and their interaction with the substrate and the surface symmetry. The interplay between the adsorbate-substrate and the metal-ligand interaction results in different coordination geometries of the iron dimers and their arrangement in the network. The intradimer spacing for the different ligands amounts to 3.8 Å to 4.7 Å and the interdimer distance varies from 10 Å to 19 Å. These diiron complexes can be considered as model systems mimicking the cofactors of biological enzymes for the design of novel catalysts at the atomic level.