Synthesis, Characterization, Photophysical and Electrochemical Studies of Ruthenium(II) Complexes with 4′‐Substituted Terpyridine Ligands and Their Biological Applications

Abstract

Three 4′‐(4‐Methylbenzoate‐benzyloxy)‐2,2′:6′,2′′‐terpyridine (MBBtpy), 4′‐(4‐Ethylbenzoate‐benzyloxy)‐2,2′:6′,2′′‐terpyridine (EBBtpy) and 4′‐(5‐(1,3‐Dimethylbenzoate)‐benzyloxy)‐2,2′:6′,2′′‐terpyridine (DMBBtpy) ligands and seven ruthenium(II) symmetrical [Ru(MBBtpy)2](PF6)2 (Ru1), [Ru(EBBtpy)2](PF6)2 (Ru2), [Ru(DMBBtpy)2](PF6)2 (Ru3) and unsymmetrical [Ru(MBBtpy)(EBBtpy)](PF6)2 (Ru4), [Ru(MBBtpy)(ttpy)](PF6)2 (Ru5), [Ru(MBBtpy)(Brttpy)](PF6)2 (Ru6), [Ru(MBBtpy)(HOttpy)](PF6)2 (Ru7) complexes were synthesized and characterized by UV/Vis, Fluorescence, FTIR, 1H & 13C NMR, ESI‐mass spectral studies and electrochemical studies. The crystal structure of HOttpy ligand was determined by single crystal X‐ray diffraction. The cyclic voltammograms of Ru(II) complexes exhibit a quasi‐reversible oxidation peak corresponding to RuII/RuIII process. The peak current Ipa and Ipc increases with increase in scan rate. The Ru(II) complexes tested for in vitro antimicrobial activity against four human pathogens and fungus Candida albicans showed good antibacterial and antifungal activity. The binding of Ru(II) complexes with calf thymus DNA was determined by UV/Vis spectroscopy. The cleavage activity of ruthenium(II) complexes studied by gel electrophoresis indicates that these complexes can cleave pUC19 DNA more efficiently when compared to that of control.

Synthesis, characterization, and evaluation of biological activities of new 4′‐substituted ruthenium (II) terpyridine complexes: Prospective anti‐inflammatory properties

“…The emission quantum yields (Φ em ) of the complexes 9, 10, and 11 in acetonitrile at room temperature (25 C) are 0.021, 0.026, and 0.016, respectively. TheΦ em values are within the range reported for Ru (II) complexes with 4 0 -substituted tpy [11] and bipyridine [28] but much lower than those reported for 4 0substituted di-tpy complexes. [44] These results demonstrate that the emission quantum yield depends on the nature of substituents at 4 0 -position of the ligand which influences the properties of Ru (II) tpy complexes.…”

“…In this regard, ruthenium (II/III) tpy complexes have been extensively investigated as anticancer and antimicrobial drugs as well as DNA binding agents. [9][10][11][12] In particular, in the design of innovative anticancer drugs, ruthenium tpy complexes have special consideration and have been evaluated against different cancer cell lines as promising alternates for the well-known diamine-dichloroplatinum (II) (cisplatin) and its derivatives. [13] Ruthenium accesses +2 and +3 oxidation states at physiological conditions and can bind to proteins, nucleic acids, sulfur, or oxygen-containing compounds in the cells.…”

“…[19,20] Moreover, ruthenium complexes also show antiviral, antibacterial, and antifungal activities. [3,11] Consequently, ruthenium complexes have emerged as an encouraging class of bioactive agents.…”

Anion Influence of Emission Properties and DFT Calculations of Diprotonated and Triprotonated Terpyridines

“…It has been established that 2,2’:6’,2’’‐terpyridine has low quantum yield fluorescence and significant emission can be achieved after specific modification of the terpyridine, especially by introducing substituent at the 4’‐position . Huang et al.…”

“…It has been established that 2,2':6',2''-terpyridine has low quantum yield fluorescence [1] and significant emission can be achieved after specific modification of the terpyridine, [2] especially by introducing substituent at the 4'-position. [3][4][5][6] Huang et al also reported that intermolecular hydrogen bonds play an essential role in forming supramolcular networks of 4'chloro-2,2':6',2''-terpyridine hexafluorophosphorate in the solid state. [7] Terpyridine (terpy) is generally known to form trans-trans conformation.…”