Abstract
Two zinc(II) complexes,
DBZ
and
DBZH
4
, that have (ZnN
3
S
2
) cores and differ in the bridging mode of the ligating backbone, effectively bind to BSA. The binding affinity varies as
DBZ
>
DBZH
4
and depends on the ligand structure. At low concentrations, both complexes exhibit dynamic quenching, whereas at higher concentrations they exhibit mixed (static and dynamic) quenching. The energy transfer mechanism from the BSA singlet excited state to
DBZ
and
DBZH
4
, is highly likely according to steady-state fluorescence and time-correlated singlet photon counting. Molecular docking was used to support the mode of interaction of the complexes with BSA and showed that
DBZ
had more energy for binding. Furthermore, antibacterial testing revealed that both complexes were active but to a lesser extent than chloramphenicol. In comparison to
DBZH
4
,
DBZ
has higher antibacterial activity, which is consistent with the binding constants, molecular docking, and particle size of adducts. These findings may have an impact on biomedicine.