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 Ba2+ as a template cation and subsequent transmetallation with UO22+. 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 barbituric acid through a supported liquid membrane is enhanced 3.7 times by carrier 2 mediated transport.
van Doorn, A. R., Rushton, D. J., van Straaten-Nijenhuis, W. F., Verboom, W., & Reinhoudt, D. N. (1992). Molecular recognition of barbiturates by a metalloreceptor. Recueil des travaux chimiques des Pays-Bas, 111(10), 421-426. https://doi.org/10.1002/recl.19921111002