Reactive nitrogen/oxygen species production by nitro/nitrosyl supramolecular ruthenium porphyrin complexes

Abstract

reports on new nitro/nitrosyl Ru-based complexes, which were synthesized with the purpose of using them as precursors to obtain supramolecular ruthenium porphyrin species ({TPyP[Ru (NO 2)(5,5 0-Mebipy) 2 ] 4 }(PF 6) 4) and ({TPyP[Ru(NO)(5,5 0-Mebipy) 2 ] 4 }(PF 6) 12). The photochemical and photophysical properties of these porphyrin species were investigated. Results show that the complex containing nitrite is able to produce NO by homolytic O-NO cleavage (F PPh NO = 0.05) while the {TPyP[Ru (NO)(5,5 0-Mebipy) 2 ] 4 }(PF 6) 12 does it by direct labilization (F PPh NO = 0.53) of the RuÀ ÀNO bond. Furthermore, a triplet quantum yield of 0.09 and 0.27 was observed for complexes containing nitrite and nitric oxide, respectively. The reactive oxygen species quantum yield for the complex {TPyP[Ru(NO) (5,5 0-Mebipy) 2 ] 4 }(PF 6) 12 (0.78) is consistent with the sum of quantum yields NO release (0.53) and triplet state (0.27), which suggests that both processes participate in the formation of the reactive species. Our results show that combining these characteristics, NO production and triplet states, on the same platform could induce a synergic effect, leading to a considerable improvement in the photodynamic action of these complexes.

Supramolecular porphyrin as an improved photocatalyst for chloroform decomposition

“…16,60 Additionally, signatures belonging to the metallic complex are also observed (see intraligand bands located at around 311 nm). 47,[61][62][63][64][65] Due to their superposition with H 2 TPyP bands, spectral signatures associated with the complex's MLCT bands centered around 470 nm are not resolved but lead to an overall increase of the spectrum baseline 49,52,56 (Fig. 2b).…”

“…, ruthenium-, rhenium- and iridium-derived) at the outer positions of porphyrins generates supramolecular structures that offer novel excited states for achieving the photo-reaction threshold while keeping original states from both the pristine porphyrin and the complexes. 46,48,49,52–56…”

“…26,[45][46][47][48][49][50][51] The attachment of metallic complexes (e.g., ruthenium-, rhenium-and iridium-derived) at the outer positions of porphyrins generates supramolecular structures that offer novel excited states for achieving the photo-reaction threshold while keeping original states from both the pristine porphyrin and the complexes. 46,48,49,[52][53][54][55][56] In this work, a supramolecular structure originated from the attachment of the RuCl(dppb)(5,5 ′ -Me-bipy) ruthenium complex at each (4-pyridyl) site of the meso-tetra(4-pyridyl) freebase porphyrin (H 2 TPyP) is used as a molecular photocatalyst for CHCl 3 decomposition, allowing the reaction to occur via visible-light OPA. The inuence of the excitation wavelength and mechanisms on the photo-reaction rates is also explored.…”

Recent advances in photorelease complexes for therapeutic applications

“…52 The more elaborate adduct RU17 combines nitric oxide release with potential other free radical formation from the porphyrin group. 53…”

Review—Tetraruthenated Porphyrins and Composites as Catalysts and Sensor Materials: A Short Review

“…The photochemical and photophysical properties of those porphyrins show that the complex containing nitrite is able to produce NO by homolytic O-NO bond cleavage. 31 In addition to bipyridine derivatives, terpyridine derivatives also can be used to generate tetraruthenated porphyrins. The [Ru(H 2 O)(ox)(Cl-tpy)] (ox = oxalate ion, Cl-tpy = 4′-Chloro-2,2′:6′,2″-terpyridine, Fig.…”