Investigation of two novel di- and tetra-nuclear Cu(II) bis(salamo)-type complexes

Abstract

Two kind of structurally different bis(salamo)-type polynuclear Cu(II) complexes, including [Cu2(HL)(EtOH)Cl2]·CH2Cl2 (1), [Cu4(L)2(EtOH)2](NO3)2·2EtOH (2) have been prepared by the reactions of the ligand H3L with CuCl2·2H2O and Cu(NO3)2·3H2O, respectively. The crystal structures of complexes 1 and 2 were characterized by X-ray crystallographic examination. Complex 1 crystallizes in triclinic system, P−1 space group, forming a unique homo-dinuclear Cu(II) complex consisting of two Cu(II) ions, one inadequately deprotonated ligand (HL)2− unit, and one ethanol molecule. The fundamental structure of complex 2 with centrosymmetric double-helical structure is two totally deprotonated ligand (L)3− units, two central Cu(II) atoms, and two coordinated ethanol molecules, which crystallizes in monoclinic system, P 21/c space group. Complexes 1 and 2 constructed by the bis(salamo)-type ligand are built into three-dimensional and two-dimensional frameworks by intermolecular interactions. Hirshfeld surfaces studies were used to quantify the various interactions of complexs 1 and 2. The spectral properties of complexes 1 and 2 were studied by ultraviolet and infrared spectroscopy. Moreover, fluorescence characteristics are carried out. Undoubtedly, these studies can enrich the structural diversity of bis(salamo)-type Cu(II) complexes.