Molecular recognition of barbiturates by a metalloreceptor

Article abstract of DOI:10.1002/recl.19921111002

Metallomacrocycle 2, possessing an immobilized Lewis-acidic uranyl cation, was synthesized by reaction of aldehyde 9 with 1,2-cis-cyclohexanediamine in the presence of Ba(2+) as a template cation and subsequent transmetallation with UO2(2+).Docking experiments with barbituric acid revealed that a -(CH2)6- spacer between the salen-uranyl and 2,6-diamidopyridine moieties of 2 is optimal.According to 1H-NMR titration experiments, the barbituric acid complex of 2 is up to 2.7 kcal*mol^-1 more stable than the complexes with five disubstituted derivatives.The flux of barbbituric acid through a supported liquid membrane is enhanced 3.7 times by carrier 2 mediated transport.