Self-assembly of mechanically interlocked and threaded rings: a HREELS andXPS study of thiol-functionalised catenane and rotaxane molecules on Au(111)

Thiol-functionalised catenane and rotaxane thin Alms were investigated in o rder to understand the self-assembly of such complex molecules on Au(111). Adsorption from the liquid phase at 300 K leads to the formation of overlay ers without long-range order, as evidenced by high-resolution electron ener gy-loss spectroscopy (HREELS). As expected for thiol adsorption, the sulfur 2p binding energies determined by X-ray photoelectron spectroscopy (XPS) a re consistent with the formation of thiolate surface intermediates. The pro perties of these films are explored as a function of annealing. Changes in vibrational spectra such as the emergence of a Au-O band and variations in core-level binding energies and intensities reveal molecular rearrangement due to partial desorption. In addition, based on coherent domain sizes esti mated by the angular width of the elastic beam intensity, annealing promote s long-range order within the adlayers. (C) 2000 Elsevier Science B.V. All rights reserved.