Unusual constructions of two Salamo-based copper(II) complexes.

wo unusual Cu(II) complexes [{Cu(L1)}2] (1) and [Cu2(L2)] (2), with an asymmetric salamo-type bisoxime ligand H2L1 were synthesized and characterized by elemental analyses, UV-Vis, fluorescent spectra, Hirshfeld surface analyses and single-crystal X-ray diffraction analyses. For the complex 1, two Cu(II) ions are penta-coordinate by N2O2 donor atoms from the (L1)2- unit and one bridged phenol oxygen atom from another (L1)2- unit. Complex 1 does not have intermolecular hydrogen bonds, formed an isolated zero dimensional structure. Meanwhile, for the complex 2, an unexpected ligand H4L2 was synthesized by aldol condensation reaction of H2L1 and acetone upon coordination, then the new ligand and Cu(II) ions combined, formed a highly symmetrical structure, and two Cu(II) ions of the complex 2 have tetra-coordinate environment. With the help of intermolecular hydrogen bonding CH⋯O interactions, a self-assembled infinite 1D supramolecular structure was formed. Meanwhile, the photophysical spectra and Hirshfeld surface analyses of the complexes 1 and 2 were also measured and discussed.