title: Molecular rotation in self-assembled multidecker porphyrin complexes.
abstract: An alkyl chain-substituted multidecker porphyrin (a cerium double-decker porphyrin (CeDDP) and a lanthanum triple-decker porphyrin (LaTDP)) complexes were arranged in a monolayer array on Au(111) substrate. By using a pulse injection deposition method, both multidecker complexes were deposited on the surface intact to form a well-defined two-dimensional array. Low-temperature scanning tunneling microscopy (STM) allowed the measurement of the topographic heights of the multidecker porphyrin complexes and visualization of their internal structures clearly. The STM images suggest that the top porphyrin ligand in CeDDP rarely rotates under nondestructive imaging condition, while the top porphyrin ligand in LaTDP exhibits flip-flop rotation even under the nondestructive imaging condition at sub-pA tunneling currents. These results provide the future applications of molecular-scale mechanical machines and single molecule storage memory.
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan. hrtanaka@sanken.osaka-u.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ikeda
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Kazuki
authors.initials: K
authors.lastname: Sada
authors.forename: Seiji
authors.initials: S
authors.lastname: Shinkai
authors.forename: Tomoji
authors.initials: T
authors.lastname: Kawai
mesh_terms: D006046:Gold / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D011166:Porphyrins / Q000737:chemistry*; D012399:Rotation; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D011166:Porphyrins; D006046:Gold