One-Dimensional Chiral Self-Assembly of Pyrene Derivatives Based on Dendritic Oligopeptides
摘要:
Supramolecular chiral columnar liquid crystals have been formed through one-dimensional self-assembly of pyrene-containing oligopeptides. Supramolecular chirality is further tuned by cooperation of intermolecular hydrogen bonding and electron donor-acceptor interactions.
Folic acid derivatives having 2-(3,4-dialkoxyphenyl) ethyl moieties have been found to exhibit thermotropic liquid-crystalline behavior. Smectic and discotic phases are observed for these compounds over wide temperature ranges. X-Ray diffraction and infrared measurements show that the formation of the smectic and discotic phases is due to the ribbon-and disk-like structures of the pterin rings of folic acid, respectively. The smectic phase is changed to a hexagonal columnar phase by the addition of alkali metal salts. This behavior is attributed to the change of the hydrogen-bonded structures from ribbon to disk induced by the ion-dipolar interactions.
Thermotropic discotic and smectic liquid crystallinity can be
induced for folic acid derivatives having octadecyl and undecyl
substituents in wide temperatures ranges, respectively; the addition of
sodium triflate to smectic liquid-crystalline folic acid leads to a change
of the assembled structures from smectic to columnar phases.
Liquid-crystalline (LC) behavior and ionic conductivities of imidazolium salts containing an l-glutamic acid moiety have been studied. The ionic conductivities of the (CF3SO2)2N− salt forming the columnar LC phase are higher than those of the Br− salt in the columnar LC state. The ionic conductivity shows a sudden decrease at the columnar–micellar cubic LC transition of the Br− salt.
Folic acid derivatives having 2-(3,4-dialkoxyphenyl) ethyl moieties have been found to exhibit thermotropic liquid-crystalline behavior. Smectic and discotic phases are observed for these compounds over wide temperature ranges. X-Ray diffraction and infrared measurements show that the formation of the smectic and discotic phases is due to the ribbon-and disk-like structures of the pterin rings of folic acid, respectively. The smectic phase is changed to a hexagonal columnar phase by the addition of alkali metal salts. This behavior is attributed to the change of the hydrogen-bonded structures from ribbon to disk induced by the ion-dipolar interactions.
One-Dimensional Chiral Self-Assembly of Pyrene Derivatives Based on Dendritic Oligopeptides
作者:Yuko Kamikawa、Takashi Kato
DOI:10.1021/ol060580q
日期:2006.6.1
Supramolecular chiral columnar liquid crystals have been formed through one-dimensional self-assembly of pyrene-containing oligopeptides. Supramolecular chirality is further tuned by cooperation of intermolecular hydrogen bonding and electron donor-acceptor interactions.