Induced smectic G phase through intermolecular hydrogen bonding

Abstract

A new series of mesomorphic complexes formed through intermolecular hydrogen bonding between p-n-alkoxybenzoic acids (where alkoxy denotes chains from propoxy-to decyloxyand dodecyloxy-) and non-mesogenic p-hydroxybutyl benzoate, have been synthesized and characterized by thermal microscopy, di erential scanning calorimetry, infrared spectroscopy (IR) and 1 H NMR studies. A detailed IR spectral investigation in the solid state and in solution suggests that the acid and phenol groups are complementary to each other, each acting as both proton donor and proton acceptor. The results of comparative thermal analyses of both free p-n-alkoxybenzoic acids and H-bonded complexes exhibited an induced crystal smectic G phase in the complexes throughout the series, its thermal range increasing with alkoxy carbon number.

Induced crystal G phase of liquid crystalline amide through inter molecular hydrogen bonding

“…The thermodynamic behavior of phases in cooling cycle are characterized by the textural observations [26] with their transition temperatures determined by polarizing optical microscope of the free p-n-alkoxy benzoic acids 3-10 and 12 (propoxy to decyloxy and dodecyloxy) and the designed hydrogen bonded amide (nAOBA:CND) are tabulated in Tables 2 and 3.The free p-nalkoxy benzoic acid [13] exhibit only marble nematic phase in the short chain 3, 4, 5 and 6 associated with smectic C phase in the longer chain of the nAOBA. These members of series show enantiotropic liquid crystalline nature over wide range of temperature from the isotropic melt.…”

“…2 shrinking the nematic phase from its isotropic state. The natural layered texture of crystal G phase [13][14][15][16][17] indicates the ordered crystalline nature. In the higher members of complexes 6-10 and 12 exhibit nematic droplets and transformed 1393 3370 3168 771 3 1672 1410 3367 3166 2956 687 4 1671 1399 3376 3167 2964 688 5 1674 1423 3371 3165 2948 692 6 1672 1398 3371 3167 2941 688 7 1669 1394 3371 3167 2935 687 8 1675 1402 3371 3167 2935 688 9 1672 1401 3373 3165 2928 697 10 1671 1398 3375 3169 2925 687 12 1672 1399 3372 3172 2924 687 Table 2 Thermal behavior of free p-n-alkoxy benzoic acids (nAOBA).…”

“…The formation of these hydrogen bonds played crucial role in self assembling process and building organized molecular structures [5,6]. In previous studies many liquid crystalline materials were synthesized with either mesomorphic or non-mesomorphic [7][8][9][10] compounds cross linked by non-covalent interactions [11,12] and with inducement of phases [13][14][15][16][17] attracted more interest that hold promise in potential applications [9] leading to supramolecular structures [18] due to its stability and directionality [19]. With untiring efforts and quest in the development, new liquid crystals are attributed between the p-n-alkoxy benzoic acids and cinnamamide.…”

Induced Smectic-A phase at low temperatures through self-assembly

“…Kato and co-workers also have shown that the intermolecular HB between 4-substituted benzoic acids and substituted pyridine derivatives can stabilize [4] or induce the mesomorphism. In continuation of our earlier work [5][6][7][8][9][10][11][12] on supramolecular liquid…”

Design, synthesis and characterization of a linear hydrogen bonded homologous series exhibiting reentrant smectic C ordering

“…Extensive work of hydrogen bonded liquid crystal by Kato and Frechet [8,9] opened a new chapter in synthesis, design and characterization of these mesogens which enables many young researchers to work in this field [23][24][25][26][27][28][29][30].…”