Structural, computational, fluorescent properties and antibacterial properties insights into perfect self-assembly of a novel ring-shaped dinuclear copper(II) complex based on a bis(salamo)-type ligand

In this work, a bis-salamo-type ligand H2L and its binuclear cyclic Cu(II) complex [Cu2(L)2]& sdot;3CH2Cl2 were prepared. Their crystal structures were analyzed by X-ray single crystal diffraction technique. Ligand H2L can form a two-dimensional layered structure through various intermolecular interactions. The two Cu atoms in the Cu(II) complex have the same coordination mode and the four coordinated Cu atoms form a twisted quadrilateral geometric configuration, which forms a one-dimensional chain structure through intermolecular interactions. Calculation of orbital energies by DFT showed that the complex has lower energy gap values and higher activity compared to H2L. Hirshfeld surface analysis and IRI analysis revealed the rich interactions between crystal molecules, which are important factors in the formation of supramolecular structures. Studies on fluorescence properties have shown that the fluorescence emission spectra of the complex were much lower than H2L. Finally, antibacterial activity experiments showed that both H2L and Cu(II) complex have good antibacterial effects, which provides new ideas for the development of more antibacterial drugs and is expected to be used in biomedical fields.