Insight into two unusual stable homomultinuclear copper (II)‐based bis (salamo)‐type complexes

Abstract

Using symmetrical bis (salamo)‐type tetraoxime ligand H3L and Cu (ClO4)2·6H2O in different solvent systems, two unusual homomultinuclear Cu (II) complexes, [Cu4(L)2(CH3CH2OH)2](ClO4)2·2H2O (1) and [Cu2(L)]n (ClO4)n·nCH3CN (2), were synthesized and characterized by single‐crystal X‐ray diffraction analyses, elemental analyses, infrared (IR), ultraviolet–visible (UV–Vis) spectroscopy, Hirshfeld surfaces analyses, and density functional theory (DFT) calculations. Complex 1 includes [Cu4(L)2(CH3CH2OH)2]2+ ion, two ClO4− counter anions, two coordinated ethanol molecules and two aquatic dissociative molecules, the two deprotonated ligand (L)3− units package around four Cu (II) ions yield a centrosymmetric helical molecules with a charged linear folding center, while complex 2 forms a 1‐D linear topology structure and is only the substitution of chloroform in the solvent system of complex 1 with acetonitrile. Coordination mode of complex 2 is widely different from that of complex 1. In the Cu (II) ions of complex 1, there are two coordination modes of Cu (II) ions, the hexa‐coordinated distorted octahedral structure and the penta‐coordinated distorted tetragonal pyramid structure, but complex 2 only has almost perfect tetragonal pyramid geometry. Fluorescence properties of H3L and its complexes 1 and 2 have also been explored.

Exploring two helical centrosymmetric homotetranuclear Cu (II) bis (salamo)‐based complexes

“…In recent 10 years, by designing salamo-based compounds containing different potential coordination sites, the structurally different complexes of transition metal (II/III) ions [21][22][23] and 3d-4f metal (II/III) ions [24][25][26] could be obtained. The obtained metal (II/III) complexes are further studied in detail and founded have potential applications in the fields of ion recognition, [27][28][29][30][31] magnetic behavior, 32 catalysis, [33,34] and antimicrobial activity, 35 the theoretically supported by Hirshfeld surfaces analyses [36][37][38] and DFT calculations.…”