Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 5: Dynamics of Molecules on Surfaces
O 5.2: Vortrag
Montag, 7. März 2016, 10:45–11:00, S053
Simultaneous AFM/STM study of chirality and on-surface chemistry of Dibenzo[7]helicene deposited on Ag(111) — •Oleksander Stetsovych1, Martin Svec1, Jaroslav Vacek2, Jana Vacek-Chocholousova2, Irena Stara2, Andrej Jancarik2, Jiri Rybacek2, Pavel Jelinek1, and Ivo Stary2 — 1Institute of Physics AS CR, Prague, CZ — 2Institute of Organic Chemistry and Biochemistry AS CR, Prague, CZ
High-resolution AFM images of single molecules brought completely new perspectives in investigation of chemical processes on surfaces. Here we investigated on-surface chemistry of Dibenzo[7]helicene deposited on Ag(111). Annealing above 100C has induced a [4+2] Diels-Alder cycloaddition reaction, which has initiated complex chemical processes on the surface. We have been able to identify an intermediate step and two final products by means of simultaneous AFM/STM measurements with Xe-tip. The intermediate products form complex chiral structures (dimers, trimers and tetramers). To understand the origin of a chiral orientation, we investigated both the racemic mixture and pure (+)-(P) enantiomer of helicene molecules deposited on the Ag(111) surface. We have found that the chiral orientation of the individual molecules as well as their complexes is driven both by chirality of helicene molecules initially deposited on the surface and annealing conditions. We have demonstrated for the first time a chemical control over the final enantiofacial adsorption of non-chiral molecules on the non-chiral metal surface that has resulted in a global mirror-symmetry breaking.