Multinuclear magnetic resonance study of N-phenyl-aza-15-crown-5 complexes with lithium, sodium and caesium ions in nonaqueous solvents

Nuclear magnetic resonances of 7Li, 23Na and 133Cs nuclei were used to study the lithium, sodium and caesium ion complexes with N-phenyl-aza-15-crown-5 (PhA15C5) in nitromethane (NM), acetonitrile (AN) and ANNM mixture solutions. The chemical shift data indicated that these cations form 1:1 cation:ligand complexes with PhA15C5. The formation constants of the resulting complexes were calculated from the computer fitting of the chemical shiftmole ratio data. The results show that the complex formation constants of PhA15C5 with these cations vary in the order of Na+>Li+>> Cs+. Complexation of the lithium ion was also studied in binary ANNM mixtures. It was found that the stability of the resulting complexes increases by an increase in the amount of NM in the solvent mixture.