Complexes of the lanthanide(III) ions with an aromatic six-nitrogen-donor macrocyclic ligand

A series of complexes of formula ML 3 X 3 •nS, in which M is La(III)-Yb(III), L 3 is C 26 H 18 N 6 , X is a mononegative ion, and S is water or methanol, were obtained by metal-templated condensation from 2,6-diformylpyridine and 1,2-diaminobenzene, as well as by metal exchange from Ba(L 3 ) 2 (ClO 4 ) 2 . The spectral properties of the complexes (IR and 1 H and 13 C NMR spectra for the diamagnetic species) closely resembled those of the Sr(II) analogue, the structure of which was established by X-ray analysis