Abstract:
Five new imine-linked ligands (H2L1, H4L2, and L3−
L5) were synthesize in two step reactions and final products were fully
characterized with spectroscopic techniques. The binding behavior of
these ligands was evaluated with the library of metal ions. However,
substantial photophysical modulations were observed with the
coordination of [Ni2+] ion to the ligand pocket. The fact that Ni2+
induced remarkable modulation in photophysical studies encouraged us
to prepare the nickel complexes of respective ligands. The resultant
coordination complexes offered interesting properties like tunable
coordination geometry, variable stereochemistry, and possibility of
electrostatic interactions which are important for biomolecular
recognition. These properties of coordination complexes encouraged
us to evaluate the antimicrobial activity of nickel complexes. All nickel
complexes have shown appreciable antibacterial activity against
Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). The SEM imaging studies were performed to know the
mechanism of cell death, and results revealed that the cell wall inhibition is the main reason for bacterial cell death. The
cytotoxicity of these complexes and their respective ligands for human cell lines was established with the HeLa cell, and
observations affirm 85−90% cell viability after 24 h
