Synthesis, characterization and electrochemical studies of a series of polypyridyl ruthenium complexes

Document Type : Original Article


1 School of Chemistry, Semnan University, Semnan, Iran

2 School of Chemistry, Sharif University of Technology, Tehran, Iran


In this study, two polypyridyl ruthenium complexes with the formula [Ru(Tttp)(opda-H2)Cl]PF6 (Fig. 2) and [Ru(Tttp)(en)(H2O)](PF6)2.3/2CH3CN (Fig. 3) were synthesized and characterized by conventional techniques such as 1HNMR, 13CNMR, UV-Vis, IR, mass spectrometry as well as elemental analysis. In these complexes, Tttp is 4'-p-toluyl-2:2':6':2"-terpyridine (Fig. 1), and opda is ortho-phenylenediamine. The 1HNMR studies showed that in the [Ru(Tttp)(opda-H2)Cl]PF6 complex, ortho-phenylenediamine was coordinated by loss of two hydrogen atoms in one of the two bqdi or s-bqdi forms (Fig. 5) . Electrochemical studies of this complex showed that in the potential region 1.55 Volts relative to NHE, there is an oxidation process that is related to one of the processes RuII(bqdi)/RuIII(bqdi) or RuIII(s-bqdi)/RuIV(s-bqdi). Similarly, in 0.924 V, there is another redox process relative to NHE that relates to one of the processes RuII(bqdi)/ RuII(s-bqdi) or RuIII(s-bqdi)/RuII(s- bqdi). In the case of the complex [Ru(Tttp)(en)(H2O)](PF6)2.3/2CH3CN, studies showed that H2O was coordinated instead of Cl. In addition, electrochemical studies also showed a quasi-reversible redox process at 1.66 V vs. NHE which could be attributed to the RuII / RuIV(O) pair.