67 research outputs found

    Controlling the Morphology of Aggregates of an Amphiphilic Synthetic Receptor through Host-Guest Interactions

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    A new amphiphilic receptor containing a macrocyclic anionic headgroup and a single alkyl chain was prepared through an efficient templated synthesis. The interdependence of the aggregation behavior and the host-guest chemistry was studied. In the absence of any guest the terminus of the alkyl chain of the receptor is included inside the hydrophobic cavity of the macrocycle (as evident from 1H NMR studies) leading to self-assembly into micrometer-long nanotubes (as evident from TEM studies). The alkyl chain can be displaced by an acridizinium bromide guest (as evident from 1H NMR and ITC), which leads to a dramatic change in aggregate size and morphology (as evident from DLS). Studies of the solubilization of Nile red suggest that the resulting aggregates are micelles with a cmc of around 35 µM. These results represent a new addition to the still small number of water-soluble amphiphilic receptors and one of the first examples in which specific host-guest chemistry controls the size and shape of nanoscale aggregates.

    Sulfur/oxygen chemistry in metal-bound thiolates

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    Vita.diazacyclooctane, bme-daco, shows its versatility i

    Sulfur/oxygen chemistry in metal-bound thiolates

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    Vita.diazacyclooctane, bme-daco, shows its versatility i

    New interlocked molecules generated from a podand containing urea units and imidazolium salts using an anion template

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    A podand containing urea units (L) was found to form interlocked structures with 2,5-dihexylamide imidazolium salts (3·X), 2,5-dihexyl imidazolium salts (4·X), and 2,5-dihexyl benzoimidazolium salts (5·X), where X=Cl-, Br-, and PF6- using anions as templates. The binding ability of L and guest molecules was evaluated by 1H NMR titrations in CDCl3. It was found that L could form complexes with guest molecules in the following order, 3·X>5·X>4·X. Stabilities of the complexes also depended on shape of the templated anions: Cl->Br -≫PF6-. Hydrogen bonding and π-π stacking interactions played an important role in the self-assembling of these interlocked molecules. © 2003 Elsevier Ltd. All rights reserved

    Diaqua{2,6-bis[N-(2-pyridinylmethyl)carbamoyl]phenolato-κ2O1,O2}zinc(II)

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    In the title compound, [Zn(C20H17N4O3)2(H2O)2], the ZnII atom, lying on a twofold rotation axis, is six-coordinated in a distorted octahedral geometry by two phenolate O atoms and two carbonyl O atoms from two 2,6-bis[(pyridin-2-ylmethyl)carbamoyl]phenolate ligands and by two water molecules. A three-dimensional network is built up from an extensive array of hydrogen bonds and π–π interactions between the pyridyl rings, with a centroid–centroid distance of 3.666 (3) Å
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