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CPP: Chemische Physik und Polymerphysik
CPP 4: New Experimental Techniques
CPP 4.5: Vortrag
Montag, 27. März 2006, 15:15–15:30, ZEU Lich
Visualizing the metal centers in metallocomplexes by scanning tunneling spectroscopy — •M.S. Alam1, V. Dremov1, P. Müller1, R. Alsfasser2, U. Kortz3, M. Ruben4, L.K. Thompson5, and J.M. Lehn6 — 1Physikalisches Institut III, Universität Erlangen — 2Institut für anorganische Chemie, Universität Freiburg — 3School of Engineering and Sciences, International University Bremen — 4Institut für Nanotechnologie, FZ Karlsruhe — 5Dept. of Chemistry, Memorial University, St. John*s, NL, Canada — 6ISIS, Université Louis Pasteur, Strasbourg, France
As the contrast in STM images mixes both topographic and electronic effects in a complicated way, mapping of complex molecules is not straightforward. However, scanning tunneling spectroscopy (STS) measurements reveal direct information about the energy levels close to moleculés Fermi level. Using our home built STM working under ambient conditions, we succeeded to combine high resolution topography mapping with simultaneous current-voltage characteristics measurements on single molecules deposited on HOPG surfaces.We present our recent results on Co [2X2], Mn [3X3] grid-type molecules, Cu20 wheel-shaped polyoxoanions, as well as on Cu coordination polymers. In our STS measurements we found a rather large signal at the expected positions of the metal centers in our molecules, i.e. the location of the individual metal ions in their organic matrix is directly addressable by STS even if these ions are covered by the organic ligands.