A new water soluble zinc-salophen complex with appended D-glucose moieties was synthesized and characterized. Its binding properties toward six aminoacids were investigated by UV-vis spectrophotometric titrations. Association constants showed to be unfavorably affected by increasing steric hindrance of the side chain. Quite surprisingly, different association constants were measured for the L and D enantiomers. These data suggest that aminoacids are bound via two interactions, zinc-carboxylate coordination and two hydrogen bonds between the ammonium group of the aminoacid and two oxygen atoms of one D-glucose moiety. Such conclusion is supported by the result of semiempirical (PM3) calculations. Notably, the KL/KD value of 9.6 observed for the association of phenylalanine rivals with the highest values found for the chiral recognition of aminoacids in water.
A New Water Soluble Zn-salophen Derivative as a Receptor for alpha-Aminoacids: Unexpected Chiral Discrimination / DALLA CORT, Antonella; DE BERNARDIN, Paolo; L., Schiaffino. - In: CHIRALITY. - ISSN 0899-0042. - 21:(2009), pp. 104-109. [10.1002/chir.20614]
A New Water Soluble Zn-salophen Derivative as a Receptor for alpha-Aminoacids: Unexpected Chiral Discrimination
DALLA CORT, Antonella;DE BERNARDIN, PAOLO;
2009
Abstract
A new water soluble zinc-salophen complex with appended D-glucose moieties was synthesized and characterized. Its binding properties toward six aminoacids were investigated by UV-vis spectrophotometric titrations. Association constants showed to be unfavorably affected by increasing steric hindrance of the side chain. Quite surprisingly, different association constants were measured for the L and D enantiomers. These data suggest that aminoacids are bound via two interactions, zinc-carboxylate coordination and two hydrogen bonds between the ammonium group of the aminoacid and two oxygen atoms of one D-glucose moiety. Such conclusion is supported by the result of semiempirical (PM3) calculations. Notably, the KL/KD value of 9.6 observed for the association of phenylalanine rivals with the highest values found for the chiral recognition of aminoacids in water.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
