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Cyclodextrin Cavity (cyclodextrin + cavity)
Selected AbstractsAn Efficient Dye-Sensitized Solar Cell with an Organic Sensitizer Encapsulated in a Cyclodextrin Cavity,ANGEWANDTE CHEMIE, Issue 32 2009Hyunbong Choi Wird der Farbstoff JK-2 in einem Cyclodextrin (CD) eingeschlossen, so ist die Ladungsrekombination verzögert und die Aggregation verhindert (siehe Bild). Eine Solarzelle mit einem solchen ,-CD/JK-2-System und einem Polymergel als Elektrolyt ergab bei ausgezeichneter Stabilität eine Gesamtumwandlungseffizienz von 7.40,%; dies ist der bislang höchste Wert für farbstoffsensibilisierte Solarzellen mit organischen Sensibilisatoren. [source] Controlling the Association of Adamantyl-Substituted Poly{N -[tris(hydroxymethyl)methyl]acrylamide} and a , -Cyclodextrin/Epichlorohydrin Polymer by a Small Drug Molecule , NaproxenCHEMISTRY & BIODIVERSITY, Issue 1 2007Danica Mislovi Abstract Two polymeric substances, a poly{N -[tris(hydroxymethyl)methyl]acrylamide} (THMMA) substituted with adamantyl moieties and a , -cyclodextrin/epichlorohydrin polycondensate, formed a host,guest type complex, which resulted in the gel formation upon mixing of these two compounds at appropriate conditions. Introduction of a drug molecule, i.e., naproxen, that was able to fill the , -cyclodextrin cavities, thus expulsing adamantyl moieties, led to disruption of such association and inhibition of gel formation. The conditions required for the association of the two polymeric components and formation of the gel, as well as the dynamics of its inhibition by addition of naproxen was established. The procedure of using solutions of two associating polymers and an appropriate drug competitor can be used at targeted viscosupplementation. [source] Enantioselective Fluorescence Sensing of Amino Acids by Modified Cyclodextrins: Role of the Cavity and Sensing MechanismCHEMISTRY - A EUROPEAN JOURNAL, Issue 11 2004Sara Pagliari Dr. Abstract Two selectors based on modified cyclodextrins containing a metal binding site and a dansyl fluorophore,6-deoxy-6- N -(N, -[(5-dimethylamino-1-naphthalenesulfonyl)aminoethyl]phenylalanylamino-,-cyclodextrin,containing D -Phe (3) and L -Phe (4) moieties were synthesized. The conformations of the two selectors were studied by circular dichroism, two-dimensional NMR spectroscopy and time-resolved fluorescence spectroscopy. Cyclodextrin 4 was found to have a predominant conformation in which the dansyl group is self-included in the cyclodextrin cavity, while 3 showed a larger proportion of the conformation with the dansyl group outside the cavity. As a consequence, the two cyclodextrins were found to bind copper(II) with different affinities, as revealed by fluorescence quenching in competitive binding measurements. Addition of D - or L -amino acids induced increases in fluorescence intensity, which were dependent on the amino acid used and in some cases on its absolute configuration. The cyclodextrin 4 was found to be more enantioselective than 3, suggesting that the self-inclusion in the cyclodextrin cavity strongly increases the chiral discrimination ability of the copper(II) complex. Accordingly, a linear fluorescent ligand N, -[(5-dimethylamino-1-naphthalenesulfonyl)aminoethyl]- N1 -propyl-phenylalaninamide, which has the same binding site and absolute configuration as 4, showed very low chiral discrimination ability. The enantioselectivity in fluorescence response was found to be due to the formation of diastereomeric ternary complexes, which were detected by ESI-MS and by circular dichroism. Time-resolved fluorescence studies showed that the fluorescence of the dansyl group was completely quenched in the ternary complexes formed, and that the residual fluorescence was due to uncomplexed ligand. [source] Sulfoalkyl ether-alkyl ether cyclodextrin derivatives, their synthesis, NMR characterization, and binding of 6,-methylprednisoloneJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2005Serena Tongiani Abstract The objective of this study is to see if random alkyl ethers of various sulfoalkyl ether cyclodextrins can be synthesized and characterized. The purpose of the alkylation was to test the hypothesis that an increase in the "height" of a cyclodextrins cavity would help in the binding/complexation of larger more structurally complex molecules. The synthesis of new cyclodextrin derivatives comprising a mixture of sulfoalkyl ether and alkyl ether substituents on the same cyclodextrin ring was performed in aqueous alkaline solutions using various sultones and alkylsulfates. The method presented provided an easy and efficient way to modify cyclodextrins avoiding the use of organic solvents and high quantities of alkylating agents and could be carried out in either a two step or "one pot" single step process. Purification was by neutralization followed by ultrafiltration. The derivatives were characterized by 1D, (1H and 13C), and a 2D NMR technique (HMQC, Heteronuclear Multiple Quantum Coherence). The combination of these techniques allowed an analysis of the degree of substitution and the site of substitution on the cyclodextrin (CD) nucleus. For both ,- and ,-CD, sulfoakylation was preferred on the 2,>,3,>,6 hydroxyls while alkylation was preferred 6,>,2,>,3. Due to the simultaneous presence of short alkyl ether chains and negatively charged sulfoalkyl ether chains, these mixed water-soluble cyclodextrin derivatives, especially those of ,-cyclodextrin, should be able to bind more complex drugs. The improved binding capacity of these new modified CDs with the model drug 6,-methylprednisolone is reported. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:2380-2392, 2005 [source] | ||||||||||