Exploration of supramolecular layer and bi-layer architecture in M(II)–PPP complexes: Structural elucidation and Hirshfeld surface analysis [PPP = 4-(3-Phenylpropyl)pyridine, M = Cu(II), Ni(II)]

Self-assembly of metal salts with N-containing ligand affords two different metal organic frameworks (MOFs) based on different metal cores, namely [Cu(ppp)2Cl2]3 (1) and [Ni(ppp)4Cl2] (2) where, ppp = 4-(3-phenyl pyridyl) pyridine, have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction analyses. Structural analyses revealed that the complexes are stabilized with the existence of several noncovalent interactions. Complex-1 shows a one-dimensional (1D) polymeric ribbon due to π–π stacking interaction and is further extended to two-dimensional (2D) supramolecular layer by multi C–H⋯π interactions. Complex-2 possesses an unusual 2D double layered supramolecular structure by C–H⋯π interactions. The diverse structures illustrate that the metal ions play significant roles in constructing the novel architectures of metal–organic complexes. An exhaustive investigation of diverse intermolecular interactions via Hirshfeld surface analysis enables quantitative contributions to the crystal packing of the title structures. The fingerprint plots associated with Hirshfeld surface clearly exposes momentous similarities and differences in the interactions experienced by each complex.