Cyclodextrins functionalized

In DMF, 6-cyclodextrin and 12a form a 1 1 complex with the aromatic ring of 12a included in the hydrophobic cavity of the 6-cyclodextrin. Electrolysis under these conditions results in a product distribution close to that obtained in DMF/MeOH mixtures 71% 2 F product, 19% LHD, and only 1% CHD [65] i.e., the hydroxy groups at the rim of the cyclodextrin function as proton donors. 

Figure 1 lV,lV-Diethylaniline bound in JJ-cyclodextrin functionalized with a rhenium complex (bipy=2,2 -bipyridyl) [6]... 

Classically, the bell-shaped dependence of rate of the enzymic reaction on pH has been attributed to general acid and base catalysis by the two histidine residues in the active site, His-12 and His-119 (66). Support for this explanation based on the kinetic properties of a model system was first provided by an observation by Breslow and co-workers that 8-cyclodextrin functionalized with two imidazole groups will catalyze the 1,2-cyclic phosphate of 4-rert-butylcatechol (67). The dependence of hydrolysis rate on pH mimics that of RNase A, and this behavior demonstrates that the presence of two imidazole functional groups on a nonionizable framework is the simplest kinetic mimic of the enzyme. 

A simpler and more general alternative relies on the ability of fi -cyclodextrin immobilized on a Sephacryl support to form host/guest complexes with a wide range of organic molecules, including chromophores [105]. On addition of cyclodextrin-functionalized Sephacryl resin 77 to the protein-labeling reactions, the modified protein is bound by the resin while unmodified protein is left in the solution. Following isolation of the resin via filtration, the captured protein... 

Catalysis by cyclodextrins may be divided into two categories (1) Catalysis by the hydroxyl groups, in which the hydroxyl groups of the cyclodextrin function as intracomplex catalysts toward the substrates included in the cayity of the cyclodextrin. (2) Effect of the reaction field, in which the cavity of the cyclodextrin serves as an apolar and sterically restricted reaction field. Both of these catalyses are important in enzymatic reactions. 

ABSTRACT. The copper(n) complexes of p-cyclodextrins functionalized with aliphatic or pseudoaromatic amines were used for the chiral recognition of unmodified amino acids. Molecular recognition, assisted by non-covalent interactions, was proved by means of thermodynamic and spectroscopic (c.d., e.p.r. and fluorescence) measurements. A cis-disposition of amino groups seems to assist enantiomeric selectivity. The copper(II)-p-cyclodextrin complexes can be used as mobile phase additives in HPLC to separate enantiomeric mixtures of unmodified aromatic amino acids. 

Receptor molecules have also been reported where remarkable enhancement of the binding process is obtained by both cavity interaction and metal-ligand co-ordination interaction [25]. For instance, P-cyclodextrin functionalized with diethylentriamine forms a zinc(II) complex that binds adamantane-2-ketone-l-carboxylate anion 330 times more strongly than the parent P-CD [26]. 

Supramolecular block copolymers can also be aeated from binary host-guest complexes, although it requires the host molecules to be tethered covalently to the polymer chains. In this fashion, Zeng et al prepared (3-cyclodextrin functional P4VP and Ad functional poly(iV-isopropylacrylamide) polymers. Complexation of both chains yielded supramolecular AB diblock... 

Pereira et al studied adducts of negatively charged lanthanide chelates with cyclodextrins, functionalized with ammonium groups. In the case of Gd(III) complexes, the authors measured PRE for aqueous protons by the... 

Teng M, Li F, Zhang B, Taha AA (2011) Electrospun cyclodextrin-functionalized mesoporous polyvinyl alcohol/Si02 nanofiber membranes as a highly efficient adsorbent for indigo carmine dye. Colloids Surf A Physicochem Eng Asp 385 229-234... 

Palaniappan A, Li X, Tay FEH, Li J, Su X (2006) Cyclodextrin functionalized mesoporous sflica films on quartz crystal microbalance for enhanced gas sensing. Sens Actuators B Chem 119 220-226 Palaniappan A, Moochhala S, Tay FEH, Su X, Phua NCL (2008) Phthalocyanine/silica hybrid films on QCM for enhanced nitric oxide sensing. Sens Actuators B Chem 129 184—187 Pejcic B, Eadington P, Ross A (2007) Environmental monitoring of hydrocarbons a chemical sensor perspective. Environ Sci Technol 41(18) 6333-6342... 

Xu C, Wang X, Wang J, Hu H, Wan L. Synthesis and [4iotoelectrical prt rties of P-cyclodextrin functionalized graphene materials with high bio-recognition capabflity. Chem Phys Lett 2010 498 162-7. 

G.U. Marten, T. Gelbrich, H. Ritter, and A.M. Schmidt, A magnetoresponsive drug dehv-ery system via P-cyclodextrin functionalized magnetic polymer brushes. Magnetics, IEEE Transactions, 49 (1), 364-372,2012. 

M. Bazhban, M. Nouri, and J. Mokhtari, Electrospinning of cyclodextrin functionalized chitosan/PVA nanofibers as a drug delivery system, Chinese J. of Pol. Sci., 31 (10), 1343-1351,2013. 

Uyar T, Balan A, Toppate L, Besenbacher F (2009) Electrospuming of cyclodextrin functionalized poly(methyl methacrylate) (PMMA) nanofibers. Polymer 50(2) 475—480, http //dx.doi. otg/10.1016/j.polymer.2008.11.021... 

Uyar, T., Havelund, R., Nur, Y, Hacaloglu, J., Besenbacher, R, Kingshott, R, 2009, Molecular filters based on cyclodextrin functionalized electrospun fibers, J Memb Sci 332 120-137. 

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