What Triggers Supramolecular Isomerism in Nonmolecular Solids? A case study of Copper Pyridazine Halides

Abstract

Molecular recognition and aggregation occurring in solution are critical events towards the nucleation and growth of a crystal. However, controlling aggregation towards a particular supramolecular assembly is difficult due to lack of information on its thermodynamics and kinetics. Hence, the occurrence of supramolecular isomers is hardly recognized. In this paper, therefore, we demonstrate a retrosynthetic analysis to interpret the occurrence of isostructures and supramolecular isomers and predict the possibility of new phases in copper halide-pyridazine-H 2O system. A significant feature of this paper is the use of crystal engineering tools, namely, synthons and tectons to interpret the phase diagram of a system. The structure-synthesis correlation discussed here provides chemical insight to evolve a synthetic protocol to interpret and predict the possibility of supramolecular isomers in metal organic solids. Graphical Abstrac [CuII(pdz)X2], 1–2; [Cu2I(pdz)X2], 3-5; [CuI(pdz)X], 6–8 and [Cu2I(pdz)3Cl2].3H2O, 9 where pdz = pyridazine, were crystallized from aqueous solution for the first time and their structure elucidation was carried out using X-ray crystallographic techniques. Growth of isostructures and supramolecular isomers in 1–9 has been interpreted in terms of tectons (I–III).