Exploring coordination behaviors, structural characterizations and theoretical calculations of structurally different Cu(II), Co(II) and Ni(II) emissive complexes constructed from a salamo-based ligand and 4,4′-bipy

Abstract

Abstract A new salamo-based ligand H2L was designed and synthesized, and its structurally different Cu(II), Co(II) and Ni(II) complexes based on ancillary ligand 4,4′-bipy were obtained. The Cu(II) complex has a mononuclear structure with the molecular formula of [Cu(L)], while the Cu(II) ion adopts a twisted four-coordinate quadrilateral geometric configuration. One dimensional chain-like supramolecular structure is formed by intermolecular interactions. In the Co(II) complex, there is a dimer structure and the molecular formula is [Co2(L)2(4,4′-bipy)]. The Co(II) ions possess five-coordinated trigonometric bipyramid geometric configurations. A two-dimensional layered supramolecular structure is formed by intermolecular interactions. The Ni(II) complex has a one-dimensional polymer structure and its molecular formula is [Ni(L)(4,4′-bipy)]n·nEtOH·nAce. The Ni(II) ions have six-coordinated octahedron geometric configurations. Through the intermolecular interactions, a three-dimensional supramolecular structure is formed. The ligand H2L and its three complexes were studied in detail by IR, UV–Vis and emissive spectra. The short-range interactions in the Cu(II), Co(II) and Ni(II) complexes were calculated by Hirshfeld surfaces analyses. The molecular orbital energy levels and molecular stability were analyzed by DFT calculations.