Berlin 2015 – wissenschaftliches Programm
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MI: Fachverband Mikrosonden
MI 4: On-Surface Polymerization (contributed Session to the Symposium SYOP, joint Session with CPP)
MI 4.1: Vortrag
Dienstag, 17. März 2015, 09:30–09:45, C 243
Covalent Coupling via Dehalogenation on Ni(111) supported Boron Nitride and Graphene — •Claudius Morchutt1,3, Jonas Björk2, Rico Gutzler3, and Klaus Kern1,3 — 1Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany — 2Department of Physics, Chemistry and Biology, IFM, Linköping University, 58183 Linköping, Sweden — 3Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
Surface-assisted covalent coupling of organic molecules represents a bottom-up approach for growing defined 2D nanostructures which are promising candidates for a variety of potential applications such as membranes for gas storage/separation, active elements in (opto)electronic devices, and catalysis. Taking a step back from the standard synthesis on (coinage) metal surfaces we explored the polymerization of 1,3,5-tris(4-bromophenyl)benzene via dehalogenation on Ni(111) supported hexagonal boron nitride and graphene by scanning tunneling microscopy and density functional theory calculations. No polymerization is observed on bare Ni, whereas on h-BN/Ni(111) and graphene/Ni(111) molecules debrominate and couple into oligomers after annealing. DFT calculations reveal that both surfaces act as a heterogeneous catalyst and reduce the dehalogenation barrier significantly. They furthermore show a strong interaction between h-BN (graphene) and surface-stabilized radicals, which in turn explains the limited oligomer size as a consequence of a diffusion-limited process.