title: Liquid crystalline order from ortho-phenylene ethynylene macrocycles.
abstract: Triangular ortho-phenylene ethynylene (o-PE) cyclic trimers represent a novel member of shape-persistent macrocycles. Shape-persistent cyclic structures remain of great interest as molecular components in the fields of supramolecular materials, host-guest chemistry, and materials science. Novel discotic liquid crystalline properties are reported from triangular-shaped o-PE macrocycles containing branched alkoxy- and/or triethylene glycol (TEG) side chains using polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The macrocycles self-assemble into thermotropic rectangular columnar (Colr) (for M1), hexagonal columnar (Colh) (for M2), and discotic nematic (for M3) mesophases at room temperature. This work shows clearly that electron-rich PE macrocycles can form LC materials. Alkyl side chains in M1 promote order, while hydrophilic side chains of M2 generate an amphiphilic structure that provides a different driving force for organization. The ability to create ordered self-assembling materials from these novel electron-rich macrocycles is important in nanotechnology.
authors.affiliation: School of Materials Science and Engineering, Hyperstructured Organic Materials Research Center, Seoul National University, Seoul 151-742, Korea.
authors.forename: Sang Hyuk
authors.initials: SH
authors.lastname: Seo
authors.forename: Ticora V
authors.initials: TV
authors.lastname: Jones
authors.forename: Helga
authors.initials: H
authors.lastname: Seyler
authors.forename: Jack O
authors.initials: JO
authors.lastname: Peters
authors.forename: Tae Hyung
authors.initials: TH
authors.lastname: Kim
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Chang
authors.forename: Gregory N
authors.initials: GN
authors.lastname: Tew