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

This contribution reports the synthesis, characterization, (1)H 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 (1)H 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 center dot center dot center dot Br interactions, thus avoiding intermolecular Zn center dot center dot center dot 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 center dot center dot center dot Br interactions. The present approach thus suggests a new method to unique supramolecular architectures for coordination metal complexes.