7 research outputs found

    Dimerisation and complexation of 6-(4'-t-butylphenylamino)naphthalene-2-sulphonate by beta-cyclodextrin and linked beta-cyclodextrin dimers

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    Published online: 19 Aug 2009This study shows that stereochemical factors largely determine the extent to which 6-(4′-t-butylphenylamino)-naphthalene-2-sulphonate, BNS− and its dimer, (BNS− )2, are complexed by β-cyclodextrin, βCD, and a range of linked βCD dimers. Fluorescence and 1H NMR studies, respectively, show that BNS− and (BNS− )2 form host–guest complexes with βCD of the stoichiometry βCD.BNS− (10− 4 K 1 = 4.67 dm3 mol− 1) and βCD.BNS2 2 − (10− 2 K 2′ = 2.31 dm3 mol− 1), where the complexation constant K 1 = [βCD.BNS− ]/([βCD][BNS− ]) and K 2′ = [βCD. (BNS− )2]/([βCD.BNS− ][BNS− ]) in aqueous phosphate buffer at pH 7.0, I = 0.10 mol dm3 at 298.2 K. (The dimerisation of BNS− is characterised by 10− 2 K d = 2.65 dm3 mol− 1.) For N,N-bis((2AS,3AS)-3A-deoxy-3A-β-cyclodextrin)succinamide, 33βCD2su, N-((2AS,3AS)-3A-deoxy-3A-β-cyclodextrin)-N′-(6A-deoxy-6A-β-cyclodextrin)urea, 36βCD2su, N,N-bis(6A-deoxy-6A-β-cyclodextrin)succinamide, 66βCD2su, N-((2AS,3AS)-3A-deoxy-3A-β-cyclodextrin)-N′-(6A-deoxy-6A-β-cyclodextrin)urea, 36βCD2ur, and N,N-bis(6A-deoxy-6A-β-cyclodextrin)urea, 66βCD2ur, the analogous 10− 4 K 1 = 11.0, 101, 330, 29.6 and 435 dm3 mol− 1 and 10− 2 K 2′ = 2.56, 2.31, 2.59, 1.82 and 1.72 dm3 mol− 1, respectively. A similar variation occurs in K 1 derived by UV–vis methods. The factors causing the variations in K 1 and K 2 are discussed in conjunction with 1H ROESY NMR and molecular modelling studies.Duc-Truc Pham, Philip Clements, Christopher J. Easton, John Papageorgiou, Bruce L. May and Stephen F. Lincol

    The potential hazards of Aspergillus sp. in foods and feeds, and the role of biological treatment: A review

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