Monomeric, dimeric and polymeric lanthanide(III) complexes of a hexaazamacrocyclic imine derived from 2,6-diformylpyridine and ethylenediamine

The macrocyclic Schiff base formed by the template condensation reaction of 2,6-diformylpyridine, ethylenediamine and the appropriate lanthanide nitrate forms mononuclear lanthanide(III) complexes, as revealed by the X-ray crystal structures of the Ce(III), Pr(III), Eu(III) and Y(III) nitrate derivatives. On the other hand, the NMR spectroscopic data indicate that the hydroxo derivatives of these complexes are of a dinuclear nature, while the X-ray crystal structure of carbonate derivative of the La(III) complex indicates formation of a 1-D coordination polymer.