A series of different substituted terpyridine-based ligands have been synthesized through well-known Kröhnke reaction. Their binding behavior was evaluated with the library of metal ions. Their complexation with Co(II), Fe(II), and Zn(II) led to interesting coordination compounds with fascinating spectroscopic properties with the formulas, [Zn(mttpy)2]PF6, [Co(mttpy)2](PF6)2, [Fe(mttpy)2](PF6)2. Their absorption and emission behaviors in dilute solutions were investigated in order to elucidate structure-property relationships and demonstrate the effect of the nature of different aryl-substituents on the terpyridine scaffold as well as a decisive role of a metal on the complexes. Photo-luminescence analysis of the complexes in acetonitrile solution revealed a transition from hypsochromic to bathochromic shift. All the compounds displayed remarkable photo-luminescent properties and different maximal emission peaks due to the different nature of functional groups. Furthermore, the ligands and complexes were evaluated for their antimicrobial potential. Docking analysis was carried out in order to analyze the binding affinity of terpyridine-based ligands and metal complexes with the receptor proteins. To get further insight into molecular orbital distributions and spectroscopic properties, DFT calculations were performed for few representative complexes. The photophysical behavior and the connections between structure and properties of the chromophores were investigated both experimentally and theoretically.

Keywords