Decorating the lanthanide terminus of self-assembled heterodinuclear lanthanum(III)/gallium(III) helicates

Arylacylhydrazones of 2,3-dihydroxybenzaldehyde are appropriate ligands for the preparation of heterodinuclear triple-stranded helicates involving high coordinated lanthanide(III) ions. In the present study, three different kinds of substituents are introduced at the ligands in order to modify the organic periphery of the coordination compounds: (1) alkoxy groups are attached to the terminal phenyl groups, (2) NH protons of the hydrazones are substituted by phenyl moieties and (3) amino acid bearing units are attached to the terminus of the ligand. The new ligands nicely form the desired triple-stranded gallium(III)-lanthanum(III) complexes [(5a-c,7,12,15)(3)GaLa] of which the highly phenylated derivative was crystallized and studied by X-ray diffraction.