DNA/BSA Binding and Antimicrobial Properties of Biguanide‐Cu(II) Complexes

The biguanide Cu(II) complexes [Cu(L 1–4 ) 2 ](ClO 4 ) 2 were synthesized and spectroscopic/analytical techniques were used to clarify their structures. Single crystals of complex [Cu(L 4 ) 2 ](ClO 4 ) 2 was obtained and its definite structure was determined by single crystal X‐ray diffraction study. The complexes [Cu(L 1–4 ) 2 ](ClO 4 ) 2 were screened for their FSds‐DNA interactions by using UV‐Vis absorption and fluorescence spectroscopies. The complexes [Cu(L 2 ) 2 ](ClO 4 ) 2 and [Cu(L 3 ) 2 ](ClO 4 ) 2 were shown to exhibit higher affinity for binding DNA. Examining the EB‐DNA interaction, it is believed that the complexes interact with DNA through a groove binding mechanism. The interaction of complexes with BSA were observed through the quenching of the fluorescence emission. Complexes [Cu(L 2 ) 2 ](ClO 4 ) 2 and [Cu(L 3 ) 2 ](ClO 4 ) 2 show moderate binding affinity to BSA through a static mode. Additionally, the Cu(II) complexes were screened for their antibacterial activities against various bacterial strains. Complexes showed potential antimicrobial activity against Salmonella typhimurium, Bacillus cereus , Salmonella typhimurium and S. aureus .