A New Class of Discotic Mesogens Derived from Tris(N-salicylideneaniline)s Existing inC_3handC_sKeto-Enamine Forms

Abstract

Two series of a unique class of columnar liquid crystals derived from tris(N-salicylideneaniline)s [TSANs] in which the proton and the electron interact with each other through the H-bonding environment are reported. The synthesis is carried out by condensing 1,3,5-triformylphloroglucinol with the respective dialkoxyanilines or trialkoxyanilines. 1H NMR and 1H-1H COSY NMR studies revealed their existence as an inseparable mixture of two keto-enamine tautomeric forms with C3h and Cs rotational symmetries instead of the expected enol-imine form. The influence of the number of peripheral alkoxy tails on the columnar mesomorphic behavior is investigated by using polarizing optical microscopy, differential scanning calorimetry, and X-ray scattering. The fluid/glassy columnar states probed for a number of representative compounds confirmed the D6h (hexagonal) or D2h (rectangular) symmetry of the columns. The electronic absorption and emission characteristics of these compounds have been studied in both mesomorphic and solution states. Of special interest, the photoluminescence spectra of solution and fluid/glassy two-dimensional structure evidently disclose the promising light generating capability of these new discotics systems.

Effect of regioisomerism on the self-assembly and photophysical behavior of 1,3,4-thiadiazole-based polycatenars

“…Indexing of one-dimensional (1D) intensity vs 2θ profile deduced from the powder 2D pattern at 90 o C shows three strong reflections at low angle region (0 < 2θ < 5 o ) with the respective spacing ratio of 1: 0.97: 0.94, which could be assigned to (010), (100) and (110) reflections from a Col ob lattice (Fig. 37 It is interesting to note that all the three molecules showed different thermal behavior, i.e. This belongs to a primitive planar space group P 1 and hence there are no reflection conditions as in the case of Col h or Col r .…”

Highly durable organic electrode for sodium-ion batteries via a stabilized α-C radical intermediate

“…The β-ketoenamine-linked compound is famous for its reversible proton transfers (tautomerism) between quinoidal and enol forms, and can be used for optical switches47, gas storage48 and energy storage49505152. The highly oxidative isomer could be a potential candidate for electrode material.…”

Design, Synthesis, and Characterization of 1,3,5-Tri(1H-benzo[d]imidazol-2-yl)benzene-Based Fluorescent Supramolecular Columnar Liquid Crystals with a Broad Mesomorphic Range

“…29 broad halo centered at 4.4 Å and a peak at 3.9 Å are also observed, which are assigned to the spacings between alkyl chains and the central π-systems, respectively. Thus, the XRD data of T−A 7 in conjunction with the textural pattern suggest that the mesophase is indeed the hexagonal columnar phase (Colh).…”