“Size-selectivity” in the template-directed assembly of dinuclear triple-stranded helicates

摘要

The self-assembly of supramolecular structures depends on a subtleinterplay of a series of different control mechanisms. Thegeometric as well as electronic complementarity of the molecularbuilding blocks is crucial for the specific formation of definedsupramolecular species. In addition, secondary effects, liketemplating, also have an important function. The templating ability ofdifferent cations in the formation of triple-stranded helicate-typecomplexes from alkyl-bridged di(8-hydroxyquinoline) ligands isinvestigated by introduction of alkyl chains of different length asligand spacers. Hereby a “size-selectivity” between the cationsand the dinuclear helicate-type complexes{(ligand)3M2} is observed. Large cationssupport the formation of big dinuclear complexes, whereas small cationsare able to template the formation of small complexes.