title: Functionalization, self-assembly, and photoswitching quenching for azobenzene derivatives adsorbed on Au(111).
abstract: We have used scanning tunneling microscopy to investigate the structure and photoswitching behavior of azobenzene molecules functionalized with bulky spacer groups and adsorbed onto Au(111). We find that positioning tert-butyl "legs" in a canted arrangement on the azobenzene phenyl rings quenches photoisomerizability of the molecule on Au(111). Addition of cyano groups at the para positions changes the molecular self-assembly significantly, but does not alter the quenched photoisomerizability. This behavior likely arises from a combination of molecule-surface interactions, molecule-molecule interactions, and alteration of azobenzene electronic structure resulting from the position-specific addition of tert-butyl groups.
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Jongweon
authors.initials: J
authors.lastname: Cho
authors.forename: L
authors.initials: L
authors.lastname: Berbil-Bautista
authors.forename: Niv
authors.initials: N
authors.lastname: Levy
authors.forename: Daniel
authors.initials: D
authors.lastname: Poulsen
authors.forename: Jean M J
authors.initials: JM
authors.lastname: Fréchet
authors.forename: Michael F
authors.initials: MF
authors.lastname: Crommie
mesh_terms: D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006860:Hydrogen Bonding; D016252:Microscopy, Scanning Tunneling; D055668:Photochemical Processes; D013499:Surface Properties
chemical_list: D001391:Azo Compounds; D006046:Gold; C009850:azobenzene