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|Title:||An effective metallohydrolase model with a supramolecular environment: structures, properties, and activities.|
|Keywords:||Binding Sites;Catalysis;Crystallography, X-Ray;Hydrolysis;Kinetics;Metalloendopeptidases - Chemistry - Metabolism;Models, Chemical;Molecular Mimicry;Molecular Structure;Nitrophenols - Metabolism;Oxidation-Reduction;Potentiometry;Water - Chemistry;Zinc Compounds - Chemistry - Metabolism;Beta-Cyclodextrins - Chemistry - Metabolism|
|Publisher:||Wiley - V C H Verlag GmbH & Co KGaA. The Journal's web site is located at http://www.wiley-vch.de/home/chemistry;Germany|
|Description:||A supramolecular inclusion complex, [Zn(L1)(H2O)2(beta-CD)](ClO4)2.9.5 H2O (1) was synthesized and characterized structurally and its first-order active species for hydrolysis of esters, [Zn(L1)(H2O)(OH)(beta-CD)](ClO4) (2), was isolated (L1=4-(4'-tert-butylbenzyl)diethylenetriamine; beta-CD=beta-cyclodextrin). The apparent inclusion stability constant of the host and the guest measured in aqueous solution was (5.91+/-0.03)x10(3) for 1. The measured values of the first- and second-order pK(a) values of coordinated water molecules were 8.20+/-0.08 and 10.44+/-0.08, respectively, and were assigned to water molecules occupying the plane and remaining axial positions in a distorted trigonal bipyramid of the [Zn(L1)(H2O)2(beta-CD)]2+ sphere according to the structural analysis of [Zn(L2)(H2O)}2(mu-OH)](ClO4)3 (3) (L2=4-benzyldiethylenetriamine). p-Nitrophenyl acetate (pNA) hydrolysis catalyzed by 1 at pH 7.5-9.1 and 25.0+/-0.1 degrees C exhibited a first-order reaction with various concentrations of pNA and 1, but the pH profile did not indicate saturated kinetic behavior. Second-order rate constants of 0.59 and 24.0 M(-1) s(-1) were calculated for [Zn(L1)(H2O)(OH)(beta-CD)]+ and [Zn(L1)(OH)2(beta-CD)], respectively; the latter exhibited a potent catalytic activity relative to the reported mononuclear and polynuclear Zn(II) species.;link_to_subscribed_fulltext|
|Other Identifiers:||Chemistry (Weinheim An Der Bergstrasse, Germany), 2007, v. 13 n. 8, p. 2402-2409|
|Type Of Material:||Article|
|Appears in Collections:||Department of Chemistry|
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