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

Abstract

Two novel homomultinuclear complexes [Co 6 (L) 2 (μ-OAc) 4 ]Á2CHCl 3 ÁCH 3 COCH 3 (1) and [Ni 2 (L)(H 2 O) 2 (Py) 2 ]Á2CHCl 3 (2) with a newly designed rigid bis(salamo)-type tetraoxime ligand (H 4 L) 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 N 2 O 2 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.