Easy access to powerful ruthenium phthalocyanine high-oxidized species

• Published in: Polyhedron 2022-05, Vol.217, p.115739, Article 115739
• Main Authors: Zaitseva, Svetlana V., Tyulyaeva, Elena Yu, Tyurin, Dmitry V., Zdanovich, Sergey A., Koifman, Oskar I.
• Format: Article
• Language: English
• Subjects: High-charged complexes; Kinetic studies; Room-temperature oxidation; Ruthenium phthalocyanine; Solvent assisted approach; β-Carotene
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2022.115739

Stable RuIIPc+• can be generated using solvent assisted approach in the mild conditions. RuIIPc+•–tBuOOH/H2O2–CH2Cl2 systems afford spectrally detectable two-oxidized species which, as well as the initial complex, succeed in β-carotene oxidation. The LUMO value of the high-charged species is their oxidative capability measure. [Display omitted] Ruthenium(III) phthalocyanine was synthesized using the solvent assisted approach from RuCl3·nH2O first compound with chlorinated solvents was observed to result in generation of stable π-cation radical RuIIPc+•, which was capable of oxidizing β-carotene. The spectral properties UV–visible, IR, EPR as well as electrochemical properties of the complexes were examined. The structure of the compound was supported by MALDI TOF and DFT calculations. The reaction of the one-oxidized species with tBuOOH and H2O2, afforded chemical generation of doubly oxidized species RuIIPc2+ and RuIIIPc+•, respectively, which were stable for several hours and were detected spectrally. All the high-charge compounds under study were found to be catalytically active in the oxidative degradation of β-carotene. The reaction was examined in dichloromethane at ambient temperature under visible light. The results showed that the dication species RuIIPc2+ is the most powerful oxidant and facilitates the immediate β-carotene oxidation followed by destruction of the intermediate products. The RuIIPc+• species turned out to be more durable, recoverable and stable under the reaction conditions. After complete β-carotene decay, the active species could readily be regenerated under the conditions of the reaction medium allowing catalytic cycle upon substrate addition. The experimentally assessed characteristics were also correlated with the electronic structure predicted by DFT analyses. As viable candidate species for catalytic systems based on ruthenium phthalocyanines, these highly charged species hold great promise for oxidation via activating oxidant, which could ensure their effective using.