title: Switching of single-molecule magnetic properties of TbIII -porphyrin double-decker complexes and observation of their supramolecular structures on a carbon surface.
abstract: Double-decker complexes based on single-molecule magnets (SMMs) are a class of highly promising molecules for applications in molecular spintronics, wherein control of both the ligand oxidative states and the 2D supramolecular structure on carbon materials is of great importance. This study focuses on the synthesis and study of 2,3,7,8,12,13,17,18-octaethylporphyrin (OEP)-Tb(III) double-decker complexes with different electronic structures comprising protonated, anionic, and radical forms. Magnetic susceptibility measurements revealed that only the anionic and radical forms of the OEP-Tb(III) double-decker complexes exhibited SMM properties. The barrier heights for magnetic moment reversal were estimated to be 207 and 215 cm(-1) for the anionic and radical forms, respectively. Scanning tunneling microscopy (STM) investigations revealed that these OEP-Tb(III) complexes form well-ordered monolayers upon simple dropcasting from dilute dichloromethane solutions. All three complexes form an isomorphic pseudo-hexagonal 2D pattern, regardless of the differences in the electronic structures of their porphyrin-Tb cores. This finding is of interest for SMM technology as ultrathin films of these materials undergoing chemical transformations will not require any detrimental reorganization. Finally, we demonstrate self-assembly of the protonated 5,15-bisdodecylporphyrin (BDP)-Tb(III) double-decker complex as an example of successful supramolecular design to achieve controlled alignment of SMM-active sites.
authors.affiliation: Department of Chemistry Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan).
authors.forename: Tomoko
authors.initials: T
authors.lastname: Inose
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tanaka
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Ivasenko
authors.forename: Toshi
authors.initials: T
authors.lastname: Nagata
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ohta
authors.forename: Steven
authors.initials: S
authors.lastname: De Feyter
authors.forename: Naoto
authors.initials: N
authors.lastname: Ishikawa
authors.forename: Takuji
authors.initials: T
authors.lastname: Ogawa
keywords: double-decker complexes; magnetic susceptibility; porphyrins; scanning tunneling microscopy; single-molecular magnets