Synthesis, characterization and aggregation/deaggregation properties of amphiphilic Schiff-base Zinc (II) complexes

The synthesis, characterization, optical, and fluorescent properties of amphiphilic Schiff-base bis(salicylaldiminato)zinc(II) complexes are reported. Detailed 1H- and DOSY-NMR, optical absorption, and fluorescence spectroscopy studies indicate the existence of aggregate species in noncoordinating solvents. The degree and type of aggregation are related to the concentration and the polarity of the noncoordinating solvent. Dilute solutions are likely characterized by the presence of defined dimers, whereas larger oligomeric aggregates are conceivably formed at higher concentrations. Moreover, a dramatic enhancement of fluorescence emission is observed in dichloromethane solutions upon deaggregation with a coordinating agent. Overall, these complexes are promising systems for the development of new supramolecular architectures and supramolecular fluorescent probes.