71 research outputs found
A standardized protocol for genomic DNA isolation from Terminalia arjuna for genetic diversity analysis
For studying genetic diversity in natural populations of Terminalia ,
a medicinal plant, our attempts to isolate high quality DNA using
several previously reported protocols and even modifications were
unsuccessful. We therefore combined CTAB based isolation, and column
based purification step, to isolate DNA from Terminalia arjuna . The
DNA isolated using this standardized protocol was high in quality and
suitable for restriction digestion and generation of random
amplification of polymorphic DNA (RAPD) and amplified fragment length
polymorphism (AFLP)
Hydroxy-benzimidazoles as blue-green emitters: Synthesis, structural and DFT studies
The new benzimidazole ligands (3a-e) were synthesized using ethyl 4-(butylamino)-3-nitrobenzoate and substituted salicylaldehyde in the presence of sodium dithionite reagent which undergoes ``one-pot'' nitro reductive cyclization. Here benzimidazole moiety acts as an electron-acceptor (A) whereas substituted 2-hydroxyphenyl moiety acts as an electron-donor (D) unit. The molecular structures were characterised by FTIR, H-1 NMR, C-13 NMR, single crystal XRD and MS analysis. Optoelectronic properties were determined by UV-vis, solution and solid photoluminescence, quantum yield and lifetime. The solvent-dependent absorption and emission were studied using both polar protic and polar aprotic solvents. All the derivatives exhibited ESIPT, especially compound ethyl 1-butyl-2-(3,5-dichloro-2-hydroxyphenyl)-1H-benzod]imidazole-5-carbox ylate (3e) displayed dual emission in both polar protic and polar aprotic solvents. The compound stability and electrochemical property were determined by thermal gravimetric analysis (TGA) and cyclic voltammetry (CV) respectively. The compounds emit intense blue-green fluorescence with high to moderate quantum yield. Also, these derivatives exhibited a high Stokes shift. The computational studies like Density-Functional Theory (DFT) and Molecular Electrostatic Potential (MEP) were conducted to provide important insights into the structure-property relationships. The crystal packing is stabilized through intermolecular hydrogen bonds (C-H center dot center dot center dot O) and intermolecular interactions (pi center dot center dot center dot pi). The findings of results help in developing novel ligands in the field of organic optoelectronics
Studies of the mesomorphic behavior of bivalent carbohydrate amphiphiles
A homologous series of bivalent glycolipids constituted of 1,3-bis-O-(-D-glucopyranosyl)-2- O-alkyl glycerol, bearing two sugar head groups and one alkyl chain on a glycerol backbone, was synthesized. The mesomorphic behaviour was investigated with the aid of polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction methods. The homologous members exhibit a smectic A phase, consistently with a partial bilayer structure. From experimental d-spacing and computationally derived length of the molecules, it is suggested that a partial interdigitation of the molecules is present in the bilayer structure
Effect of the C-2 hydroxyl group on the mesomorphism of alkyl glycosides: synthesis and thermotropic behavior of alkyl 2-deoxy-d-arabino-hexopyranosides
A homologous series of alkyl 2-deoxy-α-D-arabino-hexopyranosides and alkyl 2-deoxy-β-D-arabino-hexopyranosides were synthesized, upon glycosylation of 1-alkanols (from C<SUB>8</SUB> to C<SUB>18</SUB> alkanols) with ethyl 2-deoxy-3,4,6-tri-Ο-acetyl-1-thio-d-arabino-hexopyranoside, followed by a deprotection. The thermotropic behavior of these new types of alkyl glycosides was investigated. It was observed that the β-anomers of these alkyl glycosides, bearing nonyl to tetradecyl alkyl chain are mesomorphic, exhibiting monotropic smectic A phase. In contrast, the α-anomers are all non-mesomorphic. An effort to identify the liquid crystalline behavior of binary mixtures of the α - and β-anomers was undertaken and it was found that mixtures containing equimolar amounts of the anomers exhibited mesomorphic behavior. A fine balance of the hydrophilic and hydrophobic components within the molecule is also found to be important for the alkyl 2-deoxy glycosides to form the mesophase
Role of hydroxyl group on the mesomorphism of alkyl glycosides: synthesis and thermal behavior of alkyl 6-deoxy-β-D-glucopyranosides
A homologous series of alkyl 6-deoxy-β-D-glucopyranoside amphiphiles was prepared, in an effort to identify the role of hydroxyl group in the mesomorphic behavior of alkyl glycosides. Synthesis was performed by a chlorination of the sugar moiety in alkyl β-D-glucopyranosides with methylsulfonyl chloride in DMF, followed by a metal mediated dehalogenation to secure alkyl 6-deoxy-β-D-glucopyranosides, wherein the alkyl chain length varied from C<SUB>9</SUB> to C<SUB>16</SUB>. The mesomorphic behavior of these 6-deoxy alkyl glycosides was assessed using polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction method. Whereas the lower homologues exhibited a monotropic SmA phase till sub-ambient temperatures, the higher homologues formed a plastic phase. A partial interdigitized bilayer structure of SmA phase is inferred from experimental d-spacing and computationally derived lengths of the molecules. The results were compared with those of normal alkyl glucopyranosides, retained with hydroxyl groups at C-2-C-6 carbons, and alkyl 2-deoxy-glucopyranosides, devoid of a hydroxyl group at C-2 and the comparison showed important differences in the mesomorphic behavior
Effect of the C-2 hydroxyl group on the mesomorphism of alkyl glycosides: synthesis and thermotropic behavior of alkyl 2-deoxy-D-arabino-hexopyranosides
A homologous series of alkyl 2-deoxy-α-d-arabino-hexopyranosides and alkyl 2-deoxy-β-d-arabino-hexopyranosides were synthesized, upon glycosylation of 1-alkanols (from C8 to C18 alkanols) with ethyl 2-deoxy-3,4,6-tri-O-acetyl-1-thio-d-arabino-hexopyranoside, followed by a deprotection. The thermotropic behavior of these new types of alkyl glycosides was investigated. It was observed that the β-anomers of these alkyl glycosides, bearing nonyl to tetradecyl alkyl chain are mesomorphic, exhibiting monotropic smectic A phase. In contrast, the α-anomers are all non-mesomorphic. An effort to identify the liquid crystalline behavior of binary mixtures of the α- and β-anomers was undertaken and it was found that mixtures containing equimolar amounts of the anomers exhibited mesomorphic behavior. A fine balance of the hydrophilic and hydrophobic components within the molecule is also found to be important for the alkyl 2-deoxy glycosides to form the mesophase
Effect of the C-2 hydroxyl group on the mesomorphism of alkyl glycosides: synthesis and thermotropic behavior of alkyl 2-deoxy-D-arabino-hexopyranosides
A homologous series of alkyl 2-deoxy-alpha-D-arabino-hexopyranosides and alkyl 2-deoxy-beta-D-arabino-hexopyranosides were synthesized, upon glycosylation of 1-alkanols (from C-8 to C-18 alkanols) with ethyl 2-deoxy-3,4,6-tri-O-acetyl-1-thio-D-arabino-hexopyranoside, followed by a deprotection. The thermotropic behavior of these new types of alkyl glycosides was investigated. It was observed that the beta-anomers of these alkyl glycosides, bearing nonyl to tetradecyl alkyl chain are mesomorphic, exhibiting monotropic smectic A phase. In contrast, the alpha-anomers are all non-mesomorphic. An effort to identify the liquid crystalline behavior of binary mixtures of the alpha- and beta-anomers was undertaken and it was found that mixtures containing equimolar amounts of the anomers exhibited rnesomorphic behavior. A fine balance of the hydrophilic and hydrophobic components within the molecule is also found to be important for the alkyl 2-deoxy glycosides to form the mesophase
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