Ligand mediated structural diversity and role of different weak interactions in molecular self-assembly of a series of copper(II)-sodium(I) Schiff-base heterometallic complexes

Abstract We report three new Cu–Na heterometallic complexes namely [Cu(L1 2− )Na(NO 3 )(CH 3 OH)] ( 1 ), [Cu(L2 2− )Na(NO 3 ) (CH 3 OH)] ( 2 ) and [Cu Na (L3 3− )] n ( 3 ) where the topology of the synthon is directly governed by the π–π interaction involving the Cu-Schiff base chelate rings. The crystal structure analysis also reveals how the systematic variation in the ligand framework influences the supramolecular assembly and the mutual cooperation of different π-forces and the hydrogen bonding forces in the supramolecular assembly. The π-forces are more important than the hydrogen bonding forces in such compounds is evident from the supramolecular assembly of compound 3 . Most interesting revelation of the studies are the presence of relatively uncommon π-forces such as chelate ring⋯chelate ring and metal–π interactions in the supramolecular architecture of the complexes. The analysis of the supramolecular assembly of the complexes 1 – 3 reveals that metal-chelate rings play prominent role in the organization of the molecular complexes and should seriously consider along with other π-stacking forces.