Selective cation binding with cis,cis-1,3,5-trioxycyclohexyl based ligands: Application to ion transport and electrochemical detection and assessment of complexation by electrospray mass spectrometry

The synthesis is reported of two sets of oxa-amide ionophores based on 2-phenylglycerol and cis,cis-cyclohexane-1,3,5-triol, with ligand coordination numbers of four, five and six, Ionophores based on the hexadentate cyclohexyl triamide 9 show excellent Na+/K+ selectivity (-log K-Na,K(pot) = 3.1), and the pentadentate analogue 10 shows good Li+/Na+ selectivity (-log K-Li,Na(pot) = 2.2), solution NMR and liquid-liquid extraction studies confirmed the formation of 1:1 complexes and IR studies pinpointed the presence of amide binding, Ligands based on 2-phenylglycerol exhibited good Ca2+ selectivity which was highest for the hexadentate triamide, 6, Detailed ESMS studies revealed similar trends in ion-binding, performed under controlled conditions.