Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 87: Surface chemical reactions
O 87.2: Talk
Friday, March 30, 2012, 10:45–11:00, MA 042
Click-type on-surface formal [2+2] cycloaddition visualized by Scanning Tunneling Microscopy — •Sylwia Nowakowska1, Petra Fesser2, Cristian Iacovita1, Aneliia Shchyrba1, Christian Wäckerlin3, Saranyan Vijayaraghavan1, Nirmalya Ballav3, Kara Howes2, Jean-Paul Gisselbrecht4, Maura Crobu2, Corinne Boudon4, Meike Stöhr5, Thomas A. Jung3, and François Diederich2 — 1University of Basel, Switzerland — 2ETH Zürich, Switzerland, — 3Paul Scherrer Institute, Switzerland — 4C.N.R.S. Université de Strasbourg, France — 5University of Groningen, The Netherlands
A porphyrin module has been functionalized with one electron-rich alkyne substituent and three di(tert-butyl)phenyl moieties as imaging groups. STM measurements in combination with X-ray photoelectron spectroscopy studies demonstrated the occurrence of a formal [2+2] cycloaddition/cycloreversion between the donor-activated alkyne and the electron-deficient exocyclic double bond of TCNQ on Au(111). At low coverage, monomeric and self-assembled dimeric species of the initial compounds as well as of the reaction product, a TCNQ-conjugated porphyrin, could be visualized and manipulated with the STM tip. [1] These results motivated us to explore the self-assembly and the reactive assembly of difunctionalized porphyrins equipped with two electron-rich alkyne substituents and their reaction with electron-deficient linkers.
[1] P. Fesser et al., Chem. Eur. J., 17 (2011) 5246-5250