title: Ferrocene-Substituted Naphthalenediimide with Broad Absorption and Electron-Transport Properties in the Segregated-Stack Structure.
abstract: A new naphthalenediimide (NDI) molecule, where two ferrocene (Fc) units were directly attached to both imide nitrogens (Fc-NDI-Fc), was synthesized. The Fc units provide high crystallinity to Fc-NDI-Fc with good solubility to conventional organic solvents. The Fc units also work as electron-donating substituents, in contrast to the electron-deficient NDI unit, resulting in broad charge-transfer absorption of Fc-NDI-Fc from the UV region to 1500 nm in the solid state. The crystal structure analysis revealed that Fc-NDI-Fc formed a segregated-stack structure. The DFT calculation based on the crystal structure showed that the NDI π-orbitals extended over two axes. The extended π-network of the NDI units led to the electron-transport properties of Fc-NDI-Fc, which was confirmed using a flash-photolysis time-resolved microwave conductivity technique.
authors.affiliation: International Center for Young Scientists and Molecular Design & Function Group, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan. takai.atsuro@nims.go.jp.
authors.forename: Atsuro
authors.initials: A
authors.lastname: Takai
authors.affiliation: Department of Molecular Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sakamaki
authors.affiliation: Department of Molecular Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
authors.forename: Shu
authors.identifier: http://orcid.org/0000-0001-7851-4405
authors.initials: S
authors.lastname: Seki
authors.affiliation: Materials Analysis Station, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Matsushita
authors.affiliation: International Center for Young Scientists and Molecular Design & Function Group, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan. takeuchi.masayuki@nims.go.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takeuchi
keywords: charge transfer; electron transport; electronic structure; ferrocene; stacking interactions