Synthesis and Thermal Properties for 4-(4-Alkoxyphenoxycarbonyl)phenyl 3-Alkoxy-2-X-benzoates

Okamoto, H.; Morita, Yuki; Segawa, Yoichi; Takenaka, Shigeori

doi:10.1080/15421400590957071

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…13,14 To further utilize the unusual behavior of such gemini lipids, we thought of generating an alternative type of gemini lipids where the hydrocarbon chains are anchored via aromatic backbone, which also possess a charged headgroup residue (Figure 1). 15 Although the transfection and aggregation properties of a few cationic lipids based on aromatic backbone are known in literature, [16][17][18][19] and many aromatic backbone based compounds have also been shown to have liquid-crystalline properties, [20][21][22][23][24][25][26][27] there is no report that examines the membraneforming behavior of gemini lipids possessing aromatic backbone. Notably, the presence of sp 2 hybridized planar aromatic hydrocarbon rings at the hydrocarbon chain-polar headgroup linkage region poses interesting situations pertaining to their interlipidic interactions in the membranes as opposed to those based on pseudoglyceryl backbones, which associate with each other and the interfacial water Via hydrogen bonding and dipolar interactions.…”

Section: Introductionmentioning

confidence: 99%

Membrane-Forming Properties of Gemini Lipids Possessing Aromatic Backbone between the Hydrocarbon Chains and the Cationic Headgroup

Bhattacharya

Bajaj

2007

J. Phys. Chem. B

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Membrane-forming properties of five new gemini cationic lipids possessing an aromatic backbone between the headgroup and hydrocarbon chains have been presented. These gemini lipids differ by the number of polymethylene units [-(CH(2))(n)-] between the cationic ammonium -[N(+)(CH(3))(2)]- headgroups. The membrane-forming properties of these gemini lipids have been studied in detail by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), high-sensitivity differential scanning calorimetry (DSC), Paldan fluorescence studies, and UV-vis absorption spectroscopy. The electron micrographs and dynamic light scattering of their aqueous suspensions confirmed the formation of vesicular-type aggregates. The vesicle sizes and morphologies were found to depend strongly on the n-value of the spacer. Information on the thermotropic and hydration properties of the resulting vesicles was obtained from differential scanning calorimetry and temperature-dependent Paldan fluorescence studies, respectively. Examination of the thermotropic phase-transition properties of the lipid aggregates revealed interesting features of these lipids, which were found to depend on the length of the spacer chain. Paldan fluorescence studies indicate that the membranes of the gemini lipids are less hydrated as compared to that of the monomeric counterpart in their solid-gel state. In contrast in their fluid, liquid-crystalline phase, the hydration of gemini lipid aggregates was found to depend strongly on the length of the spacer. UV-vis absorption studies suggest an apparent H-type aggregate formation in the gemini lipid membranes in the gel states. In fluid state of the lipid membranes, H-aggregate formation was found to be enhanced depending on the length of the spacer. Such an understanding of the properties upon membrane formation from this new class of gemini lipids will be useful for further development of related gene delivery systems.

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Section: Introductionmentioning

confidence: 99%

Membrane-Forming Properties of Gemini Lipids Possessing Aromatic Backbone between the Hydrocarbon Chains and the Cationic Headgroup

Bhattacharya

Bajaj

2007

J. Phys. Chem. B

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“…In recent years, an interesting class of mesogenic compounds with a shape intermediate between the traditional rod like molecules and the conventional bent core ones, the "hockey stick-shaped compounds", have emerged as a eld of immense interest, where the "bend" has been introduced in the form of a metasubstituted alkyl or alkoxy chain in the terminal phenyl ring of normal three ring calamitic molecules. [38][39][40][41][42][43] In some other hockey stick molecules having a bent aromatic core, the angle of the molecular long axis results from a 1,3-phenylene fragment or 2,5-disubstituted heterocyclic ve-membered ring in strongly non-symmetric four-or ve-ring aromatic systems. [44][45][46][47][48][49] Some of these compounds are of considerable interest due to the occurrence of two polymorphic tilted smectic phasesthe synclinic smectic C (SmC s ) as well as the anticlinic smectic C (SmC a ) phases.…”

Section: Introductionmentioning

confidence: 99%

Optical, dielectric and visco-elastic properties of a few hockey stick-shaped liquid crystals with a lateral methyl group

Chakraborty

Das

Das³

et al. 2013

J. Mater. Chem. C

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Measurements of birefringence (Dn), dielectric permittivity (3 k , 3 t ), elastic moduli (K 11 , K 33 ) and rotational viscosity (g 1 ) have been carried out on the nematic (N) phase of a few hockey stick-shaped compounds 4-(3n-alkyloxy-2-methyl-phenyliminomethyl)phenyl 4-n-alkyloxycinnamates with a lateral methyl group inserted between the m-alkyloxy chain and the azomethine connecting group. Interestingly, a dual characteristic (i.e. partially calamitic like and partially bent-core like) is revealed in the N phase of these compounds. The SmC a -N transition is found to be of first order in nature while the SmC s -N transition is either second order or weakly first order. All the mesogens exhibit a temperature dependent inversion in the static dielectric anisotropy (D3 ¼ 3 k À 3 t ) from positive to negative values on entering the SmC a phase. Remarkably in the entire nematic range, the bend elastic modulus (K 33 ) is substantially lower than the corresponding splay modulus (K 11 ). The rotational viscosity coefficient (g 1 ) as obtained by extracting the relaxation time (s 0 ) values from two precise, independent probing methods, viz. the capacitive decay technique and the optical phase-decay-time measurement method, are slightly higher than those of many known calamitic systems. Moreover, the activation energy (E a ) calculated from the viscosity data is found to be considerably higher in the nematic phase than those obtained for conventional calamitics. The observed behaviours are accounted for by considering the intriguing shape-determined inter-molecular interactions and molecular associations appearing in the mesophase.

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New hockey stick compounds with a lateral methyl group showing nematic, synclinic and anticlinic smectic C phases

Chakraborty

Das²,

Das

et al. 2011

Liquid Crystals

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Synthesis and Thermal Properties for 4-(4-Alkoxyphenoxycarbonyl)phenyl 3-Alkoxy-2-X-benzoates

Cited by 3 publications

References 9 publications

Membrane-Forming Properties of Gemini Lipids Possessing Aromatic Backbone between the Hydrocarbon Chains and the Cationic Headgroup

Membrane-Forming Properties of Gemini Lipids Possessing Aromatic Backbone between the Hydrocarbon Chains and the Cationic Headgroup

Optical, dielectric and visco-elastic properties of a few hockey stick-shaped liquid crystals with a lateral methyl group

New hockey stick compounds with a lateral methyl group showing nematic, synclinic and anticlinic smectic C phases

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