Synthesis, characterization and antimicrobial property in vitro of supramolecular coordination polymers bearing brominated Schiff base ligand

In this study, two supramolecular coordination polymers of Co(II) and Zn(II) based on brominated Schiff base (E)-4-bromo-2-((quinolin-6-ylimino)methyl)phenol (HL) were synthesized and characterized by using elemental analysis, IR spectroscopy and NMR spectroscopy. Furthermore, the crystal structures of HL, CoL2 (І) and ZnL2 (II) were determined by single crystal X-ray analysis. It was revealed that the bromine-related interaction played important role in the self-assembly of HL supramolecular network. The crystal structural investigations revealed that І and II were isomorphous with the same geometry around the metal atom and similar structural feature. The stable four-membered chelate structure resulted from coordination between the metal(II) ion and deprotonated bidentate ligand. And supramolecular coordination polymers of І and II formed diverse architecture through multiple hydrogen bondings, π···π interactions and halogen-related interactions. Antimicrobial activities of polymers were tested toward four bacteria and five phytopathogenic fungi. І and II showed higher activities toward the tested microorganisms than HL. Furthermore, the photoluminescence results indicated that HL and II accompanied with better fluorescence properties in the ultraviolet region. The ligand (HL) and its Co, Zn complex (I and II) were synthesized, characterized and tested for antifungicidal and photoluminescence property. II displayed a wider range antimicrobial activity compared to HL and I, especially toFusarium solani. Meanwhile, II accompanied with a fluorescence properties in the violet region. [Display omitted] •Halogen bonding play an important role in the construction of HL crystal engineering.•Coordinate bond and noncovalent interaction promote the formation of coordination polymer.•II displays a wider range antimicrobial activities against fungi and bacteria.•II and HL accompanied with better fluorescence properties in the violet region.