The non-coordinating anion 1,1,3,3-tetracyano-2-propoxy-propenide as an anion-π donor in cis-diaquabis(2,2′-dipyridylamine)zinc and its cadmium analog: Luminescence properties, Hirshfeld analysis and central-atom induced polymorphism

Abstract

The synthesis, structure and properties of cis-diaquabis(2,2′-dipyridylamine)zinc bis(1,1,3,3-tetracyano-2-propoxy-propenide), [Zn(H2O)2(2,2′-dpa)2][tcnopr]2, I, and its isomorphous Cd analog, II, are reported. These two coordination compounds were prepared through hydrothermal reactions of Zn(II)/Cd(II) acetate with potassium 1,1,3,3-tetracyano-2-propoxy-propenide (tcnopr–=[(NC)2CC(OPr)C(CN)2]−) in the presence of 2,2′-dipyridylamine (dpa=C10H9N3) as a co-ligand. Both new compounds were fully characterized by elemental analysis, FT-IR spectroscopy, powder XRD and X-ray single-crystal diffraction.Single-crystal X-ray analysis has revealed that compounds I and II are isostructural containing octahedrally coordinated metal ions, and exhibit 3D supramolecular architectures, including multiple anion-π interactions. Furthermore, the photoluminescence properties in the solid state at room temperature and Hirshfeld surfaces analysis to understand the packing have also been investigated in detail.