Discogens Possessing Aryl Side Groups Synthesized by Suzuki Coupling of Triphenylene Triflates and Their Self‐Organization Behavior

Abstract

Pd‐catalyzed Suzuki cross‐coupling reactions between arylboronic acids and bromoarenes have been applied widely in the synthesis of liquid‐crystalline materials. However, aryl triflate derivatives have been less used despite their high chemical tolerance, reactivity, and chemical accessibility. In this report, three series of discogens have been synthesized in good yields from appropriate triphenylene triflate precursors by Suzuki coupling reactions with various commercial arylboronic acids (e.g., aryl = phenylene, thiophene, naphthalene, triarylamine, carbazole, and fluorene). The synthesized discogens display broad mesophase ranges and high thermal stabilities. Moreover, those bearing triarylamine, carbazole, and fluorene side groups are also blue‐light emitters. The availability of the triflate precursors coupled with their highly efficient cross‐coupling with commercial arylboronic acids make this strategy extremely versatile and attractive for the design of new functional materials.

Molecular Engineering of Mesomorphic Fluorene-Bridged Triphenylene Triads: Thermotropic Nematic/Columnar Mesophases, and p-Type Semiconducting Behavior

“…37 Accordingly, phenyl substituents connected at the bay positions "1" strongly hamper face-to-face stacking and mesomorphic properties, due the discrepancy between both the natural spacings of rodlike and disklike mesogens (typically 4.5 Å against 3.5 Å, respectively), while the substitutions in peripheral positions "2" (dyad) and "2,7" (triad) promote the induction of columnar-like mesomorphism. 38 For such dyads, and for triads with the disc-like unit in the center, the peripheral rodlike segments could just insert between alkyl chains respecting the optimal self-organization of both moieties. Lateral arrangement and stacking should on the contrary conflict for triads with the rodlike segment in the center, as examined hereafter for a series of dialkylfluorene units connected at both ends to TP species.…”

“…In this study, the molecular triads were synthesized in one single step by Suzuki cross-coupling between the commercially available dialkyl fluorene-2,7-diboronic acids and the readily accessible 3,6,7,10,11-pentakis(alkoxy)triphenylen-2-yl triflates (Scheme 1, 2a−c in the Supporting Information), the latter as a versatile alternative to bromide homologues. 38 The combination of two different fluorene-2,7-diboronic acids (Scheme 1, R 1 = C n H 2n+1 , n = 1, 8) and three triphenylene triflates (Scheme 1, R 2 = C o H 2o+1 , o = 1, 6, 8/R 3 = C m H 2m+1 , m = 6 or 8) resulted in six novel triads, thereafter abbreviated as FTP-nom. These six new triads were obtained in good yields and fully characterized by 1 H NMR and HRMS.…”

Board‐like Fused‐Thiophene Liquid Crystals and their Benzene Analogs: Facile Synthesis, Self‐Assembly, p‐Type Semiconductivity, and Photoluminescence

“…Columnar discotic liquid crystals(DLC) possessing polycyclic aromatic cores are well known as mesophase semiconductors, [51][52][53][54][55] the discotic column formed by the stacked aromatic cores functiona se lectron transport pathways with the one-dimensional features of am olecular wire, whereas the peripheral alkyl chains serve as insulators. DLC semiconductors are presently being investigated as active materials in printed organic thin-film devices,s uch as organic photovoltaic solar cells (OPV), [56] organic field-effect transistors (OFET), [26] and organic light-emitting diodes (OLED).…”

Butterfly Mesogens Based on Carbazole, Fluorene or Fluorenone: Mesomorphous, Gelling, Photophysical, and Photoconductive Properties

“…[4] We have recently developed an efficient strategy based on a tandem of model reactions, namely the Pd(PPh 3 ) 4 -catalyzed Suzuki-Miyaura cross-coupling and the FeCl 3 -catalyzed Scholl oxidative annulation reactions, to construct novel butterfly-like shape molecules showing mesomorphous and promising hole and electron charge carriers behaviors (DTT, CPTO, Figure 1). [24][25][26] The key of this generic methodology for the synthesis of these new ditriphenylenes (CTP, LTP, FTP) lies on the availability of specific carbazole-, fluorene-and fluorenone-containing polybromide precursors and/or corresponding boronic esters (or to a lesser extend their hydroxyl homologs), [27] not always easily accessible, as reported in Scheme 1. Numerous strategies have been developed for the synthesis of carbazolebased materials and most of them involve bromide derivatives as starting materials.…”