Anthraquinone-Based Discotic Liquid Crystals

Abstract

The syntheses of six room-temperature discotic liquid crystals based on an alkoxy-anthraquinone (AQ) framework is described. Differential scanning calorimetry, X-ray diffraction (XRD), and cross-polarized microscopy were used to identify phases and confirm phase-transition temperatures. Cross-polarized microscopy results suggest columnar discotic structures at room temperature. However, the AQ derivatives also undergo mesophase-to-mesophase transitions, which are attributed to rectangular- to hexagonal-columnar discotic transitions based on XRD analysis. Furthermore, some of the compounds display remarkable liquid crystalline phase stability that spans from -50 to 150 degrees C, a useful temperature range for organic materials applications. The different AQ derivatives did not exhibit electronic perturbations, as all compounds have absorption onsets of approximately 400 nm. Finally, solution cyclic voltammetry of the AQ derivatives was carried out to determine the redox potentials, diffusion coefficients, and electron transfer rate constants. All AQ derivatives had E(1/2) values that ranged between -1.52 and -1.70 V vs Fc/Fc(+). Diffusion coefficients and electron transfer rates for all AQ derivatives ranged between 0.4 and 7.1 x 10(-6) cm(2) x s(-1) and 0.9 and 5.2 x 10(-3) cm x s(-1), respectively.

Smart Lipid Nanotubes for Easy Formation of Gold‐Lipid Hybrid Nanotubes and Tunable Gold Superstructures

“…To be able to effectively reduce the Au(III) salt to its Au 0 form, AQ acts as an electron donor. AQ is a well‐known redox‐active group that can be reduced and oxidized both chemically and electrochemically . Previous studies have shown that Au(III) can be reduced by hydroquinones (reduction product of the AQ group under specific conditions) in the presence of NaOH above pH 7.0 at room temperature and that increasing the pH increases the reducing power of the hydroquinones .…”

Aggregation‐Dependent Chromism and Photopolymerization of Aminoanthraquinone‐Substituted Diacetylenes

“…X‐ray diffraction (XRD) patterns in the wide‐angle region (Figure 4B), which provide structural insight into the organization of the diacetylene sidechains and anthraquinone units of the ADA monomers, [ 56–58 ] further reveal significant structural differences between the Y‐phase and R‐phase ADA films. Specifically, the XRD trace of Y‐phase ADA (Figure 4B, yellow pattern) features several peaks between 2θ = 12° and 24°, generally associated with alkyl chain organization.…”

“…Specifically, the XRD trace of Y‐phase ADA (Figure 4B, yellow pattern) features several peaks between 2θ = 12° and 24°, generally associated with alkyl chain organization. [ 57,58 ] In particular, the sharp reflection at 2θ = 23° (corresponding to d spacing of 3.9 Å) in the Y‐phase likely accounts for the stacking of the alkyl chains containing diacetylene units. [ 59 ] The peak at 2θ = 25.6 (3.48 Å) is attributed to π–π stacking of the anthraquinone moieties.…”

“…[ 59 ] The peak at 2θ = 25.6 (3.48 Å) is attributed to π–π stacking of the anthraquinone moieties. [ 57 ]…”

1-Hydroxy-3-(3-methylbut-2-enyloxy)anthracene-9,10-dione

“…2.1. Synthesis of 1,3-Dihydroxyanthracene-9,10-dione (3) 1,3-Dihydroxyanthracene-9,10-dione (3) was prepared from compounds 1 and 2 according to method described in [5] with some modifications. A mixture of compounds 1 (4.17 g, 34.1 mmol), 2 (1.5 g, 9.73 mmol) and concentrated sulphuric acid (39 mL) was refluxed at 120˝C for 2 h. The reaction mixture was then cooled to room temperature and was poured into ice-water (50 mL).…”