Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 29: Organic/bio Molecules on Metal Surfaces III
O 29.7: Vortrag
Dienstag, 12. März 2013, 12:00–12:15, H38
On-Surface Polymerization of 1,4-Diethynylbenzene on Cu(111) — •Johanna Eichhorn1, 2, Wolfgang M. Heckl1, 2, and Markus Lackinger1, 2 — 1Department of Physics & TUM School of Education, Tech. Univ. Munich, 80799 Munich, Germany — 2Deutsches Museum, 80538 Munich, Germany
The last decade has witnessed a growing interest in the use of organic materials in light-emitting diodes, and optoelectronic devices. In this context, the conjugated polymer poly(phenylene butadiynylene) has shown promising properties like photo-, and electroluminescence.[1] A previous study already reported that 1,4-diethynylbenzene (DEB) can be polymerized into PPB strands within Cu2+ functionalized mesoporous materials.[2] For a more facile preparation, we study polymerization of DEB on catalytically active Cu(111) surfaces by means of ultra-high vacuum scanning tunneling microscopy.
Upon adsorption at room temperature, DEB self-assembles into a densely packed structure controlled by weak hydrogen bonds (C-H...triple bond). Subsequent thermal annealing results in drastic structural changes, where wormlike chains containing Y-shaped trimers, cross-linked tetramers and dumbbell shaped hexamers were observed. The thermal stability of these surface-supported structures extends up to 450°C, thereby proofing covalent bond formation. The observed topology of the covalent networks can only be explained by at least two different coupling schemes: di- and trimerization.
[1] X. Zhan, et al., Adv. Mater., 2000, 12, 51-53.
[2] V. S.-Y. Lin, et al., J. Am. Chem. Soc., 2002, 124, 9040-9041.