Induced Crystal-G Phase through Intermolecular Hydrogen Bonding Part XIV: Influence of Alkyl Carbons of p-Hydroxybenzoates on Phase Distribution of Induced Phase (original) (raw)
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Among hydrogen bonded (H bonded) LC systems formed by identical molecules (symmetric dimers), the most well known are 4 alkyloxybenzoic acids with alkyl substituents containing more than seven CH 2 groups. At present, there exists a vast database on their structure, their thermal behavior, and on dimerization of acids [23-26] and interaction with surface [27, 28]. Short chain 4 alkoxybenzoic and 4 alkylbenzoic
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Brazilian Journal of Physics, 2016
A homologous series of hydrogen-bonded liquid crystals (HBLCs) are synthesized and characterized. Intermolecular hydrogen bonding occurs between 4methoxycinnamic acid (4MCA) and p-n-alkyloxy benzoic acids (nOBA, where n = 3, 7 to 12). These binary complexes have been obtained by following well-designed synthesis route. The subsequent binary complexes have been characterized by polarizing optical thermal microscopy (POM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). The present work explains the details of the association between the mesogenic phase behavior and H-bonding in the homologous series of 4MCA + nOBA. Nematic phase is interrelated with the closed dimers between acid molecules through the formation of strong hydrogen bonds. But, high concentrations are linked to the manifestation of smectic phases that disturb the local order of the nematic phase. As a result, the higher-order mesophases are observed in the present binary complex series. The inclusion of nematic LC (4MCA) in the nOBA alters the melting temperature and the clearing temperature as lower than those of the individual. Also, the wide mesophase regions of the present series are identified compared to those of the constituent mesogens. The optical tilt angle of binary mixtures for smectic C phase and thermal stability factors of the mesogenic phases have been discussed.
Molecular Crystals and Liquid Crystals, 2018
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Journal of the Iranian Chemical Society, 2007
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Brazilian Journal of Physics, 2009
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New H-Bonded Complexes and Their Supramolecular Liquid-Crystalline Organizations
European Journal of Organic Chemistry, 2008
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