Synthesis and Self-Assembly of Donor−Spacer−Acceptor Molecules. Liquid Crystals Formed by Single-Component “Complexes” via Intermolecular Hydrogen-Bonding Interaction
2005; American Chemical Society; Volume: 38; Issue: 5 Linguagem: Inglês
10.1021/ma047999l
ISSN1520-5835
AutoresJianwei Xu, Cher Ling Toh, Xueming Liu, Shaofeng Wang, Chaobin He, Xuehong Lu,
Tópico(s)Crystallization and Solubility Studies
ResumoA series of donor−spacer−acceptor molecules, 4-{[n-(4-stilbazoyl)]alkyloxy}benzoic acid, where n is the number of carbon atoms in alkyloxy chain and equals to 6, 8, 10, and 12, respectively, for 6a−d, were synthesized. The molecular "complexes" formed by identical 6a−d molecules generated hydrogen-bonded liquid-crystalline polymers by connecting a rigid donor and a rigid acceptor of the molecules via hydrogen-bonding interaction. The thermal behaviors were studied by differential scanning calorimetry, polarizing microscopy and X-ray diffraction. The phase transition temperature of 6a−d on both cooling and heating decreased steadily with the increase in length of the spacer. The hydrogen-bonding interaction in 6a−d was investigated by X-ray photoelectron spectroscopy and FT-IR spectroscopy. The intermolecular hydrogen-bonding interaction was evidenced by the fact that there were two characteristic bands at 2450 and 1920 cm-1 in the FT-IR spectra and the change in binding energy of N 1s by 0.72−0.88 eV relative to its reference compound trans-4-octyloxy-4'-stilbazole (7) were observed.
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