Experimental observation of supramolecular carbonyl–π/π–π/π–carbonyl assemblies of CuII complex of iminodiacetate and dipyridylamine

A mononuclear CuII complex [Cu(IDA)(2,2′-dypam)(H2O)]·H2O (1) where H2IDA and 2,2′-dypam are iminodiacetic acid and 2,2´-dipyridylamine, respectively, has been synthesized and characterized by X-ray single crystal structure analysis. The Cu(II) atom exhibits an unsymmetrical elongated octahedral coordination type 4 + 1 + 1. X-ray crystallography reveals that complex (1) has an unprecedented fac-O2 + N(apical) IDA conformation, in the trans-site of Cu–N (IDA-like) bond, in contrast with structural co-relations for complexes with Cu/(IDA or IDA-like)/N-heterocyclic donor ratio 1/1/2 and closely related compounds fac-NO + O(apical) IDA-like conformation and one N-heterocyclic donor in the trans-site to the Cu–N (IDA-like) bond. These findings are attributed to the influence of π–π stacking, C–H⋯π interactions in the molecular recognition process. Moreover, the aromatic moieties of 2,2′-dypam are engaged in carbonyl⋯π interaction with the non-coordinated carbonyl groups of IDA ligand and giving rise to a remarkable supramolecular carbonyl–π/π–π/π–carbonyl interactions.