A multivalent hexapod: conformational dynamics of six-legged molecules in self-assembled monolayers at a solid-liquid interface

Hong Xu; Andrea Minoia; Zeljko Tomović; Roberto Lazzaroni; E W Meijer; Albertus P H J Schenning; Steven De Feyter

doi:10.1021/nn900131k

A multivalent hexapod: conformational dynamics of six-legged molecules in self-assembled monolayers at a solid-liquid interface

ACS Nano. 2009 Apr 28;3(4):1016-24. doi: 10.1021/nn900131k.

Authors

Hong Xu¹, Andrea Minoia, Zeljko Tomović, Roberto Lazzaroni, E W Meijer, Albertus P H J Schenning, Steven De Feyter

Affiliation

¹ Division of Molecular and Nano Materials, Department of Chemistry, and Institute for Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, B-3001, Leuven, Belgium.

PMID: 19361208
DOI: 10.1021/nn900131k

Abstract

A molecular hexapod having a benzene core and six oligo(p-phenylene vinylene) (OPV) legs is an ideal system to probe various types of (intramolecular) dynamics of individual molecules in physisorbed self-assembled monolayers at a solid-liquid interface. Scanning tunneling microscopy reveals that molecules adsorb in 2D crystalline as well as disordered domains. Strikingly, not all molecules have the six OPV units in contact with the graphite substrate: 4% of the molecules in the 2D crystalline domains and up to 80% of the molecules in the disordered domains have one or two OPV units desorbed. In addition, the presence of such a defect promotes the coexistence of another defect adjacent to it. Time-dependent STM experiments and molecular dynamics simulations reveal in detail the different dynamics involved and the multivalent nature of the interactions between hexapod and surface.