The functionalized cyclodextrin 6-deoxy-6-[1-(2-amino)ethylamino]-beta-cyclodextrin was synthesized, and an NMR, EPR, pH-metric, and calorimetric investigation was carried out in aqueous solution in order to ascertain its behaviour towards protonation and copper(II) complex formation. The thermodynamic parameters of the ternary complex formation with alanine, phenylalanine and tryptophan enantiomeric pairs were also determined (25-degrees-C and I = 0.1 mol dm- 3). No thermodynamic enantioselectivity was observed in these systems, while a chiral, though poor, discrimination was observed in LEC: c.d. spectra also show enantiomeric stereoselectivity. The results of the present investigation, compared with previously reported results, suggest the occurrence of a cis-complex reversible trans-complex equilibrium in such systems.
The functionalized cyclodextrin 6-deoxy-6-[1-(2-amino)ethylamino]-beta-cyclodextrin was synthesized, and an NMR, EPR, pH-metric, and calorimetric investigation was carried out in aqueous solution in order to ascertain its behaviour towards protonation and copper(II) complex formation. The thermodynamic parameters of the ternary complex formation with alanine, phenylalanine and tryptophan enantiomeric pairs were also determined (25-degrees-C and I = 0.1 mol dm- 3). No thermodynamic enantioselectivity was observed in these systems, while a chiral, though poor, discrimination was observed in LEC: c.d. spectra also show enantiomeric stereoselectivity. The results of the present investigation, compared with previously reported results, suggest the occurrence of a cis-complex reversible trans-complex equilibrium in such systems.
COORDINATION PROPERTIES OF 6-DEOXY-6-[1-(2-AMINO) ETHYLAMINO]-BETA-CYCLODEXTRIN AND THE ABILITY OF ITS COPPER(II) COMPLEX TO RECOGNIZE AND SEPARATE AMINO-ACID ENANTIOMERIC PAIRS
BONOMO, Raffaele;MACCARRONE, Giuseppe;RIZZARELLI, Enrico
1993-01-01
Abstract
The functionalized cyclodextrin 6-deoxy-6-[1-(2-amino)ethylamino]-beta-cyclodextrin was synthesized, and an NMR, EPR, pH-metric, and calorimetric investigation was carried out in aqueous solution in order to ascertain its behaviour towards protonation and copper(II) complex formation. The thermodynamic parameters of the ternary complex formation with alanine, phenylalanine and tryptophan enantiomeric pairs were also determined (25-degrees-C and I = 0.1 mol dm- 3). No thermodynamic enantioselectivity was observed in these systems, while a chiral, though poor, discrimination was observed in LEC: c.d. spectra also show enantiomeric stereoselectivity. The results of the present investigation, compared with previously reported results, suggest the occurrence of a cis-complex reversible trans-complex equilibrium in such systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
