Hollow Six‐Stranded Helical Columns of a Helicene

Щербина, М. А.; Zeng, Xiangbing; Tadjiev, Timur R.; Ungar, Goran; Eichhorn, S. Holger; Phillips, Karen E. S.; Katz, Thomas J.

doi:10.1002/anie.200903658

Cited by 104 publications

(51 citation statements)

References 38 publications

(14 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The columns of the helicene are believed to be the stiffest among the compounds used in the present study, due to their intertwined 6-strand helical structure shown in Figure 1c. 19 Thus, the observed behavior of the helicene follow the general trend revealed in this study, that axial orientation of the column is promoted by their increasing bending modulus.…”

Section: Resultssupporting

confidence: 71%

“…18 The columns it forms are hollow 13 2 helices with each asymmetric unit comprising six molecules; hence, the columns are rigid six-stranded helices (Figure 1c). 19 The ranking in order of increasing bend elastic constants K 3 should be CBZ dendron, HAT6, HAT6-TNF complex, helicene. The fraction of main (non-H, non-F) atoms in the stiff aromatic portion of the molecule is around 30% for the CBZ dendron and HAT6 and about 40% in the HAT6ÀTNF complex and the helicene.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Columnar Liquid Crystals in Cylindrical Nanoconfinement

et al. 2015

Self Cite

View full text Add to dashboard Cite

Axial orientation of discotic columnar liquid crystals in nanopores of inorganic templates, with the columns parallel to the axis of the nanochannels, is considered desirable for applications such as production of molecular wires. Here, we evaluate experimentally the role of the rigidity of the LC columns in achieving such orientation in nanopores where the planar anchoring (i.e., columns parallel to wall surface) is enforced. We studied the columnar phase of several discotic compounds with increasing column rigidity in the following order: dendronized carbazole, hexakis(hexyloxy)triphenylene (HAT6), a 1:1 HAT6-trinitrofluorenone (TNF) complex, and a helicene derivative. Using 2-D X-ray diffraction, AFM, grazing incidence diffraction, and polarized microscopy, we observed that the orientation of the columns changes from circular concentric to axial with increasing column rigidity. Additionally, when the rigidity is borderline, increasing pore diameter can change the configuration from axial back to circular. We derive expressions for distortion free energy that suggest that the orientation is determined by the competition between, on the one hand, the distortion energy of the 2-d lattice and the mismatch of its crystallographic facets with the curved pore wall in the axial orientation and, on the other hand, the bend energy of the columns in the circular configuration. Furthermore, the highly detailed AFM images of the core of the disclinations of strength +1 and +1/2 in the center of the pore reveal that the columns spiral down to the very center of the disclination and that there is no amorphous or misaligned region at the core, as suggested previously.

show abstract

Section: Resultssupporting

confidence: 71%

mentioning

confidence: 99%

Columnar Liquid Crystals in Cylindrical Nanoconfinement

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…There have been numerous reported examples of intracolumnar helical order in thermotropic 35,36,37 columnar systems -see e.g. review ref.…”

mentioning

confidence: 99%

Helically Twisted Chiral Arrays of Gold Nanoparticles Coated with a Cholesterol Mesogen

et al. 2015

Self Cite

View full text Add to dashboard Cite

Gold nanoparticles have been prepared, surface-functionalized with a 1:1 molar mixture of a hexylthiol ligand and a chiral mesogenic ligand consisting of a cholesterylbenzoate attached via an undecylthiol spacer. Grazing incidence Xray diffraction showed that, upon annealing, a columnar liquid crystal (LC) structure develops, with the nanoparticles forming strings on a regular oblique 2d lattice. Synchrotron radiation circular dichroism is substantially enhanced upon the isotropic-LC transition. In the proposed structural model, layers of gold columns rotate by a small angle relative to their neighbors, the columns winding around a helical axis. The work demonstrates that it is possible to obtain chiral LC superstructures from nanoparticles coated with chiral mesogen without the addition of a separate liquid crystal or chiral dopants. The results provide direction in the development of plasmonic metamaterials interacting selectively with circularly polarized light.

show abstract

“…Columnar liquid crystal phases, having 2D positional order, have come a long way since their first discovery in 1977 in discotic molecules . Subsequent years have seen columnar mesogens increasing in complexity and variety of shapes (star, bent core, bowl, helicene, heterocycle, T‐ and X‐shape) and types of non‐bonded interactions (H‐bonding, donor‐acceptor, ionic, coordination) …”

Section: Introductionmentioning

confidence: 99%

New Type of Columnar Liquid Crystal Superlattice in Double‐Taper Ionic Minidendrons

Fan

Wang

et al. 2019

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

Wedge‐shaped molecules, such as dendrons, are among the most important building blocks for directed supramolecular self‐assembly. Here we present a new approach aimed at widening the range and complexity of potential mesophases by introducing double‐tapered mesogens. Two series of compounds are presented, both alkali metal salts (Li, Na, Cs) of 3,4,5‐tris‐alkoxybenzoic acid with a second tapered tris‐alkoxyaryl group attached at the end of an alkoxy chain. The double‐tapered compounds all display an unusual hexagonal columnar phase consisting of one ionic and three non‐ionic columns per unit cell. The cation size has an unexpectedly drastic effect on unit cell size. Unlike most columnar phases, the current phases show unusually high dimensional stability on heating, and high stiffness in spite of being 80–85 % aliphatic, attributed to their molecular topology. The described approach may lead to co‐assemblies of multifunctional materials, for example, parallel p‐ and n‐semiconducting nanowires or parallel ionic and electronic conductors.

show abstract

Hollow Six‐Stranded Helical Columns of a Helicene

Cited by 104 publications

References 38 publications

Columnar Liquid Crystals in Cylindrical Nanoconfinement

Columnar Liquid Crystals in Cylindrical Nanoconfinement

Helically Twisted Chiral Arrays of Gold Nanoparticles Coated with a Cholesterol Mesogen

New Type of Columnar Liquid Crystal Superlattice in Double‐Taper Ionic Minidendrons

Contact Info

Product

Resources

About