Long-Lived Polypyridyl Based Mononuclear Ruthenium Complexes: Synthesis, Structure, and Azo Dye Decomposition

Abstract

Two mononuclear ruthenium complexes [(bpy)RuL/L](ClO) ([1]/[2]) (bpy-2,2' bipyridine, L = 2,3-di(pyridin-2-yl)pyrazino[2,3-f][1,10]phenanthroline) and L = 2,3-di(thiophen-2-yl)pyrazino[2,3-f][1,10]phenanthroline have been synthesized. The complexes have been characterized using various analytical techniques. The complex [1] has further been characterized by its single crystal X-ray structure suggesting ruthenium is coordinating through the N donors of phenanthroline end. Theoretical investigation suggests that the HOMOs of both complexes are composed of pyridine and pyrazine unit of ligands L and L whereas the LUMOs are formed by the contribution of bipyridine units. The low energy bands at ∼480 nm of the complexes can be assigned as MLCT with partial contribution from ligand transitions, whereas the rest are ligand centered. The complexes have shown Ru/Ru oxidation couples at E at 1.26 (70 mV) V and 1.28 (62 mV) V for [1] and [2] vs Ag/AgCl, respectively, suggesting no significant role of distal thiophene or pyridine units of the ligands. The complexes are emissive and display solvent dependent emission properties. Both complexes have shown highest emission quantum yield and lifetime in DMSO (ϕ = 0.05 and τ = 460 ns and λ at 620 nm for [1]; ϕ = 0.043 and τ = 425 ns and λ at 635 nm for [2]). Further, the long luminescent lifetime of these complexes has been utilized to generate reactive oxygen species for efficient azo dye decomposition.

Ruthenium(II)‐Polypyridyl‐Based Sensor Bearing a DPA Unit for Selective Detection of Cu(II) Ion in Aqueous Medium

“…The crystal structure exhibited that Ru(II) centre is bound to the N atoms of phenanthroline moiety with a distorted O h geometry leaving the nitrogen atoms of DPA end uncoordinated. Such kind of binding mode has also been observed in earlier cases . The Ru−N bond distances in Ru‐L are in the range of 2.044(4)−2.059(4) Å, with trans N−Ru−N angles in the range of 172.60(17)−174.70(15)°.…”

Comparative study of the anchorage and the catalytic properties of nanoporous TiO2 films modified with ruthenium (II) and rhenium (I) carbonyl complexes

“…On the other hand, several reports on the general, flexible and modular ruthenium(II) complexes synthesis of type cis-Ru(N,N) 2 X 2 (where N,N is a dinitrogenated ligand and X is an halide such as chloride) conclude that the electronic effects produced by the ligands nature and coordination position are fundamental to control their electrochemical properties [16][17][18][19]. In addition, numerous studies on electron transfer and transport processes in solar cells based on TiO 2 with ruthenium (II) complexes have demonstrated successful results in energy conversion [16,20]. These findings encourage the development of new methods to immobilize ruthenium-based catalysts onto semiconducting or conducting supports with the purpose of obtaining heterogeneous catalysts.…”

“…Among several reported compounds, the ruthenium (II) and rhenium (I) complexes harboring carbonyl ligands have promising catalytic properties with the choice of suitable bidentate ligands [24][25][26][27]. This type of catalysts could have important applications in new devices for the conversion of CO 2 to value added molecules such as CO, which represent an important technological and environmental challenge [16,21,26,27].…”

DNA Microviscosity Converts Ruthenium Polypyridyl Complexes to Effective Photosensitizers

“…Our previous report on structurally similar RPCs, suggests the generation of ROS by RPCs. [9] Our hypothesis claims the ROS mediated DNA nick generation as a mode of metal complex action. These phenomena successively lead to a series of events when studied in vivo.…”

“…The synthesis of RPCs has reported earlier. [9] The synthesized RPCs generate ROS via the radiative decay engineering mediated by local DNA microviscosity. Ultimately, this leads to light-induced DNA cleavage, and eventually, results in nicked circular DNA (Scheme 1c).…”