title: Coupled molecular switching processes in ordered mono- and multilayers of stimulus-responsive rotaxanes on gold surfaces.
abstract: Interfaces provide the structural basis for function as, for example, encountered in nature in the membrane-embedded photosystem or in technology in solar cells. Synthetic functional multilayers of molecules cooperating in a coupled manner can be fabricated on surfaces through layer-by-layer self-assembly. Ordered arrays of stimulus-responsive rotaxanes undergoing well-controlled axle shuttling are excellent candidates for coupled mechanical motion. Such stimulus-responsive surfaces may help integrate synthetic molecular machines in larger systems exhibiting even macroscopic effects or generating mechanical work from chemical energy through cooperative action. The present work demonstrates the successful deposition of ordered mono- and multilayers of chemically switchable rotaxanes on gold surfaces. Rotaxane mono- and multilayers are shown to reversibly switch in a coupled manner between two ordered states as revealed by linear dichroism effects in angle-resolved NEXAFS spectra. Such a concerted switching process is observed only when the surfaces are well packed, while less densely packed surfaces lacking lateral order do not exhibit such effects.
authors.affiliation: †Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.|‡BAM-Federal Institute for Materials Research and Testing, Unter den Eichen 44-46, 12203 Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Heinrich
authors.affiliation: †Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.|‡BAM-Federal Institute for Materials Research and Testing, Unter den Eichen 44-46, 12203 Berlin, Germany.
authors.forename: Christoph H-H
authors.initials: CH
authors.lastname: Traulsen
authors.affiliation: ‡BAM-Federal Institute for Materials Research and Testing, Unter den Eichen 44-46, 12203 Berlin, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Holzweber
authors.affiliation: †Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Richter
authors.affiliation: †Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.
authors.forename: Valentin
authors.initials: V
authors.lastname: Kunz
authors.affiliation: †Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Kastner
authors.affiliation: §Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Sven O
authors.initials: SO
authors.lastname: Krabbenborg
authors.affiliation: §Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Jurriaan
authors.initials: J
authors.lastname: Huskens
authors.affiliation: ‡BAM-Federal Institute for Materials Research and Testing, Unter den Eichen 44-46, 12203 Berlin, Germany.
authors.forename: Wolfgang E S
authors.initials: WE
authors.lastname: Unger
authors.affiliation: †Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Schalley