17 research outputs found
Unexpected formation of vesicular aggregates in aqueous solutions of n-octyl 1-thio-alpha-d-talopyranoside - marked effects of intramolecular hydrogen bonding
Reflection on the State of the Union: From Crisis to Crisis? Or in a State of Perpetual Crisis?
Discussion about the future of the European Union (EU) is now taking place at 27. At the Bratislava Summit on September 16, the United Kingdom (UK) was not invited to participate considering the recent results of the referendum.
The Bratislava roadmap identified a series of policy areas that the EU ought to address: boosting up unity, addressing the migration crisis and external borders, strengthening cooperation to enforce internal and external security, and providing to the economic and social development of the Union. The roadmap appears more as a wish list for European leaders than a strategic common set of policies taking the Union towards a certain future.
This policy paper seeks to reflect on the issues facing the EU and its Member States. Several aspects have been identified as critical for the Union: security and defense, European economy/ies, the populist turn of European politics, and two critical challenges confronting the Union: climate change and Brexit.Ope
Cholesteric carbohydrate liquid crystals incorporating an intact glucopyranose moiety
Recently, the first monosaccharide derivatives containing a fully intact monosaccharide and two vicinal OH-groups which display thermotropic chiral mesophases were synthesized. These liquid crystals have a rigid core, with a trans-decalin-like skeleton incorporating the D-glucopyranose ring, substituted with an alkoxylated polarizable aromatic group, e.g. a phenyl 4-octyloxybenzoate, on one side and an alkoxyphenyl group at the anomeric centre. On the basis of the focal-conic fan-like texture displayed and the existence of a blue phase in the UV, we expected the cholesteric helix to have a very short pitch. The compounds possessed an exceptionally high helical twisting power. Extrapolation of these data to dopant concentrations of 100 % also indicates a very short pitch (30 -90 nm)
Non-Amphiphilic Carbohydrate Liquid Crystals Containing an Intact Monosaccharide Moiety
A chiral rigid moiety which forms the basis of a new class of non-amphiphilic carbohydrate liquid crystals has been developed. This moiety contains a fully intact glucopyranose ring embedded in a trans-decalin structure. The original carbohydrate is substituted so that only two hydroxyl groups are left, resulting in derivatives with reduced hydrophilicity. The substituents R and X-R’ on the 4,6-Oylidene ß-D-glucopyranoside are in the equatorial position and can be varied extensively, using straightforward synthetic procedures. Investigations as to the requirements for R and X-R’ for inducing liquid-crystalline behavior have shown that at least one of the substituents should contain a large, polarizable aromatic moiety. An aromatic Schiff base fulfils this requirement.
Meeting Minutes
Meeting regarding revised senate charter, committees, Student Government Association evaluation, post tenure review, president\u27s evaluation, appointments and athletics
Selective oxidation of polysaccharides, a tool for carbohydrate-based alternatives for Carbopol®
The Synthesis and Properties of Some Mesogenic 3-O-Alkyl Derivatives of D-Glucitol and D-Mannitol
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The crystal structure of heptyl 1-thio-α-d-glucopyranoside, a member of a new homologous series of mesogenic carbohydrate derivatives
The crystal structure of heptyl 1-thio-α-d-glucopyranoside, C13H26O5S, is monoclinic, space group P21, with Z = 2, a = 6.013(1), b = 7.324(1), c = 17.536(4) Å, β = 98.21(2)°, V = 764.4 Å3, Dcalc = 1.279 g.cm−3. The crystal involves a bilayer head-to-head molecular packing with interdigitizing alkyl chains. The carbohydrate moieties are hydrogen-bonded in finite chains which include all the oxygen atoms and which are linked1 into a network by the minor component of the three-center bond from HO-6. The crystal structure is transformed into a smectic A liquid crystal phase at 96.8° (ΔH 34.6 kJ.mol−1) that shows a periodicity of 23.1 Å. The clearing point is at 138.3° (ΔH 2.2 kJ.mol−1