Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 14: Postersitzung (Adsorption an Oberflächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Phasenübergänge, Rastersondentechniken, Struktur und Dynamik reiner Oberflächen)

O 14.64: Poster

Montag, 8. März 2004, 18:00–21:00, Bereich C

STM investigations of very large macrocycles adsorbed on surfaces — •Iordan Kossev and Moritz Sokolowski — Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstr. 12, 53115 Bonn, Germany

Rotaxanes and catenanes are of interest for the investigation on mechanically interlocked molecules [1]. A large tetralactam - macrocycle (961.3 amu), used as a building block for rotaxanes and catenanes, was deposited onto the Au(111) surface from a thermal evaporation cell. STM images were taken for different coverages at room temperature. At a coverage of less than one monolayer, it was found that the macrocycles form small clusters at step edges and surface defects, leaving large terraces uncovered. At a coverage around one monolayer, the molecules form disordered structures, which remain disordered after annealing to 423 K. Presumably, the reason for these observations is the week interaction between the Au surface and the molecules, in combination with a strong hydrogen – bonding between the molecules. Further investigations on the ordering of these molecules on more reactive surfaces like Ag(111) and Cu(111) are under progress. The macrocycles were kindly supplied by C. Schalley and F. Vögtle. This work was supported by the DFG (SFB 624). [1] J.-P. Sauvage, Acc. Chem. Res. 31, (1998) 611.