Browsing by Author "Ousaka, Naoki"

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Alkali Metal Ion-enhanced Threading of a Perylenediimide-ound Polymer Chain through a Double-stranded Spiroborate Helicate with a Bisporphyrin Unit
(2017-07-01)
Ousaka, Naoki
;
Yamamoto, Shinya
;
Hayashi, Naoki
;
Li, Ming-Chia
;
Ho, Rong-Ming
Threading of a poly(ethylene glycol) (PEG) chain linked to a perylenediimide unit at one end with a bulky stopper at the other end through an inner cavity of a bisporphyrin-based double-stranded spiroborate helicate was remarkably accelerated in a specific solvent, in which the PEG chain enfolded sodium cations coordinating to the negatively charged spiroborate helicate, thus forming a 1: 1 inclusion complex with the perylenediimide sandwiched between the bisporphyrin unit.
Chirality Control and Its Memory at Microphase-Separated Interface of Self-Assembled Chiral Block Copolymers for Nanostructured Chiral Materials
(2017-09-01)
Li, Ming-Chia
;
Ousaka, Naoki
;
Wang, Hsiao-Fang
;
Yashima, Eiji
;
Ho, Rong-Ming
Here, we show the induced chirality of an achiral chromophoric dye as a joint of polylactide-containing chiral block copolymers (BCPs*) driven by self-assembly, giving the achiral dyes preferentially arranged in a one-handed helical array at the microphase-separated interface. This helical arrangement of the achiral dyes can be "memorized" after hydrolysis of the polylactides in the BCPs* and serves as a chiral template for further chirality induction of different achiral dyes, probably through attractive aromatic pi-pi interactions at the interface, producing nanostructured chiral materials with tunable circular dichroism signals at desired wavelengths.