Control over Nanostructures and Associated Mesomorphic Properties of Doped Self‐Assembled Triarylamine Liquid Crystals

Abstract

We have synthesized a series of triarylamine-cored molecules equipped with an adjacent amide moiety and dendritic peripheral tails in a variety of modes. We show by (1) H NMR and UV/Vis spectroscopy that their supramolecular self-assembly can be promoted in solution upon light stimulation and radical initiation. In addition, we have probed their molecular arrangements and mesomorphic properties in the bulk by integrated studies on their film state by using differential scanning calorimetry (DSC), variable-temperature polarizing optical microscopy (VT-POM), variable-temperature X-ray diffraction (VT-XRD), and atomic force microscopy (AFM). Differences in the number and the disposition of the peripheral tails significantly affect their mesomorphic properties associated with their lamellar- or columnar-packed nanostructures, which are based on segregated stacks of the triphenylamine cores and the lipophilic/lipophobic periphery. Such structural tuning is of interest for implementation of these soft self-assemblies as electroactive materials from solution to mesophases.

Triphenylamine- and triazine-containing hydrogen bonded complexes: liquid crystalline supramolecular semiconductors

“…29 However, few examples have been described in which TPA is part of a mesogen that arranges in a columnar LC phase. [30][31][32][33] In addition, charge transport properties in the LC phase have not been reported to date.…”

Unravelling the Pathway Complexity in Conformationally Flexible N‐Centered Triarylamine Trisamides

“…This control can be achieved by applying a supramolecular approach for the preparation of functional materials . For example, Giuseppone and co‐workers studied in detail the self‐assembly of N ‐centered triphenylamine‐trisamide in apolar solvents and the photo‐induced supramolecular polymerization upon oxidation of triphenylamine into triphenylammonium in the presence of chloroform . The improved conductive properties, in combination with easy processability, highlight that self‐assembly is an attractive strategy to achieve well‐performing supramolecular electronics .…”

“…[15][16][17][18][19][20][21] For example,G iuseppone and co-workers studied in detail the selfassembly of N-centered triphenylamine-trisamidei na polar sol-vents and the photo-induced supramolecular polymerization upon oxidation of triphenylamine into triphenylammonium in the presenceo fc hloroform. [22,23] The improved conductive properties, in combination with easy processability,h ighlight that self-assembly is an attractive strategy to achievew ell-performing supramolecular electronics. [24,25] In addition, Seu and Kim have demonstrated that opposite helicals enses in photooxidizedt riphenylamine stacks can be induced by applying circularly polarized light of opposite handedness,o pening an ew route towards the formation of supramolecular chiral conductors.…”

Covalently Trapped Triarylamine‐Based Supramolecular Polymers

“…These primary structuresu sually show cooperative mechanisms of polymerization, and their columnar primary stacks can be further self-assembled in variouss uperstructuresi ncluding bundles of fibers and gels. [2][3][4][5][6][7][8] Because of their supramolecular packing, and because triarylamines are prone to be (photo)oxidized, these fibers can be doped to access hole-transporting nanowires and conducting materials with peculiar electronic and optical properties. [5,[9][10][11] Still, the supramolecular polymerization of triarylaminesu sually leads to soft nano-objectsa nd materials that would benefit of being mechanically strengthened.…”

“…Their local structure rests on the collinear arrangement of their nitrogen center which is maintained by π–π stacking and supplementary hydrogen bond interactions (implemented for instance by the addition of amide functions at the periphery of the triarylamine core). These primary structures usually show cooperative mechanisms of polymerization, and their columnar primary stacks can be further self‐assembled in various superstructures including bundles of fibers and gels . Because of their supramolecular packing, and because triarylamines are prone to be (photo)oxidized, these fibers can be doped to access hole‐transporting nanowires and conducting materials with peculiar electronic and optical properties .…”