Binary and Ternary Metallo-b-cyclodextrins of 6A-[Bis(carboxylatomethyl)amino]-6A-deoxy-b-cyclodextrin

摘要: The binary metallo-β-cyclodextrins formed by 6A-[bis(carboxylatomethyl)amino]-6A-deoxy-β-cyclodextrin ([M(βCDida)], where M2+ = Co2+, Ni2+, Cu2+ and Zn2+) are characterized log(K/dm3 mol–1) 7.29±0.01, 9.74± 0.02, 8.89±0.03 6.08±0.02, respectively, in aqueous solution at 298.2 K I 0.10 mol dm–3 (NaClO4), is the stability constant. ternary [M(βCDida)] (R)- (S)-tryptophanate, [M(βCDida)(R)-Trp] – [M(βCDida)(S)-Trp]– , 5.49±0.04 5.16±0.07, 6.33±0.04 6.34±0.02, 6.91±0.02 6.99±0.01, 5.34±0.02 5.36±0.04, when Zn2+. For [M(βCDida)(R)-Trp]– [M(βCDida)(S)-Trp]–, pKa values of 8.07±0.04 8.4±0.1, 7.45±0.02 7.88±0.04, 8.46±0.09 8.40±0.01, 8.92±0.05 8.7±0.2 found Zn2+, attributed to protolysis an aqua ligand occupying a sixth coordination site on .