Construction of novel hexanuclear Co(II) and dinuclear Ni(II) bis(salamo)-type complexes

Two novel homomultinuclear complexes [Co-6(L)(2)(mu-OAc)(4)]center dot 2CHCl(3)center dot CH3COCH3 (1) and [Ni-2(L)(H2O)(2)(Py)(2)]center dot 2CHCl(3) (2) with a newly designed rigid bis(salamo)-type tetraoxime ligand (H4L) were synthesized and characterized by elemental analyses, Fourier transform infrared (FT-IR) spectra, UV-Vis absorption spectra, and X-ray single-crystal diffractions. Complex 1 is a novel triple-decker symmetrical six-core cluster structure with twofold axis and inversion center. The Co(II) atoms were sandwiched between the bis(salamo)-type ligands and possess two different geometries of distorted tetragonal pyramid and octahedron, respectively. Complex 2 possesses a dinuclear structure and the Ni(II) atoms are located in the N2O2 cavities of the ligand, and axial coordination atoms come from the coordinated water and pyridine molecules. Both Ni(II) atoms adopt distorted octahedral geometries. The interactions were quantitatively determined by Hirshfeld surfaces analyses of complexes 1 and 2. The coordination ratios were determined by studying the fluorescence properties of complexes 1 and 2. The results of fluorescence titration experiment show that the metals to ligand binding ratios are 6:2 and 2:1 for complexes 1 and 2, respectively.

Automated summary

Two novel homomultinuclear complexes were synthesized and characterized with a newly designed rigid bis(salamo)-type tetraoxime ligand. Complex 1 is a symmetrical six-core cluster structure with Co(II) atoms sandwiched between the ligands, while complex 2 has a dinuclear structure with Ni(II) atoms located in the N2O2 cavities of the ligand. The coordination ratios were determined by studying the fluorescence properties, showing different metal to ligand binding ratios for each complex.