The complexation of calcium(II) and lanthanide(III) cations with the phosphate substitute (carboxymethoxy)succinate (CMOS), as studied by magnetic resonance spectroscopy

Abstract

Abstract The complexation of trisodium (carboxymethoxy)succinate (Na 3 CMOS) with calcium(II) and with lanthanide(III) cations has been studied using NMR spectroscopy. Structural information has been obtained from lanthanide‐induced shifts (LIS), T 1 relaxation rate enhancements and vicinal 1 H coupling constants. CMOS forms 1:1 and 1:2 complexes in which it mainly acts as a tetradentate ligand via the three carboxylate groups and the ether oxygen. LIS measurements on non‐racemic mixtures of Na 3 CMOS indicate self‐association of the Ln(III) complexes at [CMOS] 0 > 0.01 M.