Structural Characterization, Hirshfeld Analyses, Fluorescence,and Catalytic Oxidase Properties of New Cu(II) and Co(II) Halogen-SubstitutedSalamo-Based Complexes

Two mononuclear Cu(II) and Co(II) halogen-substituted salamo-based complexes of the formulas [Cu(L)] and [Co(L)(H2O)2] have been synthesized and characterized by elemental analyses, FT-IR and UV-Vis absorption spectra, and X-ray crystallography. The Cu(II) complex has crystallized in the monoclinic system, space group P21/n with Cu(II) atom located in the N2O2 cavity. In the Co(II) complex, the center Co(II) atom has exhibited a slightly distorted octahedral geometry with halogen-substituted salamo-based bisoxime forming the basal N2O2 coordination plane and two oxygen atoms of two coordinated water molecules in the axial positions. Non-covalent interactions like hydrogen bonding and π···π stacking interactions are operative in construction of supramolecular architectures. The crystal structures and supramolecular features of the complexes have been discussed in details. Hirshfeld surfaces analyses has indicated stability of both complexes. The Cu(II) complex has demonstrated excellent bio-inspired catalytic properties towards oxidative coupling of 2-AP in MeCN medium. Fluorescence properties of H2L and its Cu(II) and Co(II) complexes have also been discussed.