New molecular architectures by aggregation of tailored zinc(ii) Schiff-base complexes

This contribution reports the synthesis, characterization, 1H NMR, optical absorption and fluorescence properties of a bis(salicylaldiminato)Zinc(II) Schiff base complex, 1, having dipodal, alkyl ammonium bromide derivatized side chains in the salicylidene rings. The comparison of 1H NMR and optical spectroscopic properties of 1 with those of the closely related amphiphilic alkyl derivative allowed getting insights into the nature of species in solutions. Present data suggest the existence of Zn⋯Br interactions, thus avoiding intermolecular Zn⋯O interactions, as usually occur in the absence of other coordinating species. SEM images of samples obtained by drop-casting from dichloromethane solutions of 1 reveal the existence of branched nanostructures, consistent with intermolecular Zn⋯Br interactions. The present approach thus suggests a new method to unique supramolecular architectures for coordination metal complexes.