Lattice-water tweaked Cis-Trans isomerism of a copper(II)-dipyridylamine-azide complex and their aggregation features

Abstract

This work highlights an interesting study on lattice-water mediated cis-trans isomerism of hydrated mononuclear copper(II) complexes, [Cu(dpa)2(N3)2].xH2O (x = 1,2) containing bidentate chelatant 2,2′-dipyridyl amine (dpa) and co-ligand, azide ion (N3−) and their aggregation characteristics. A variation in the water–methanol (v/v) solvent mixture leads to a successful synthesis of the geometric isomers of the mononuclear hydrated copper(II) complexes. X-ray crystallography evaluates the crucial role of lattice water along with various non-classical forces for the isomeric existence of the copper complexes. Thermal gravimetric analysis, Hirshfeld surface and energy framework analysis attribute the significant contribution of dispersive forces in the formation and preferential isolation of the geometric isomers. Further, the aggregation properties of the geometric isomers have been assessed with spectroscopic characterization attributing an interesting change in the photophysical, structural and morphological features of the molecular aggregates. The facets of the structural and physicochemical properties of the geometrical conformers and their molecular aggregates have also been unveiled.

Keywords

• Cis-trans isomerism
• Lattice water
• Supramolecular architectures
• Synthesis
• X-ray crystallography