Study of the structure and spectral properties of radical anions of Zn complexes of porphyrins by the method of density functional theory

Parkhots, O. P.; Ivashin, N. V.

doi:10.1134/s0030400x0902009x

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…−2.4 V vs SHE in THF) as the chemical reductant. The UV–vis spectra of the reduced PorZn species exhibit absorption bands at 710, 820, and 920 nm (Figure ), which are characteristic features of transiently generated zinc–porphyrin compounds with reduced ligands. , Upon exposure of the reduced PorZn species to air, rapid regeneration of PorZn was observed by UV–vis spectroscopy (Figure and Figure S12). The instability of these reduced species has precluded full characterization thus far.…”

Section: Resultsmentioning

confidence: 99%

Electroreduction of CO₂ Catalyzed by a Heterogenized Zn–Porphyrin Complex with a Redox-Innocent Metal Center

et al. 2017

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Transition-metal-based molecular complexes are a class of catalyst materials for electrochemical CO2 reduction to CO that can be rationally designed to deliver high catalytic performance. One common mechanistic feature of these electrocatalysts developed thus far is an electrogenerated reduced metal center associated with catalytic CO2 reduction. Here we report a heterogenized zinc–porphyrin complex (zinc(II) 5,10,15,20-tetramesitylporphyrin) as an electrocatalyst that delivers a turnover frequency as high as 14.4 site–1 s–1 and a Faradaic efficiency as high as 95% for CO2 electroreduction to CO at −1.7 V vs the standard hydrogen electrode in an organic/water mixed electrolyte. While the Zn center is critical to the observed catalysis, in situ and operando X-ray absorption spectroscopic studies reveal that it is redox-innocent throughout the potential range. Cyclic voltammetry indicates that the porphyrin ligand may act as a redox mediator. Chemical reduction of the zinc–porphyrin complex further confirms that the reduction is ligand-based and the reduced species can react with CO2. This represents the first example of a transition-metal complex for CO2 electroreduction catalysis with its metal center being redox-innocent under working conditions.

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Section: Resultsmentioning

confidence: 99%

Electroreduction of CO₂ Catalyzed by a Heterogenized Zn–Porphyrin Complex with a Redox-Innocent Metal Center

et al. 2017

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“…Similar event (three anodic waves) was recorded in an investigation of zinc(II) 5,10,15,20tetraphenylporphyrin studied at the same scan rate 83 . Following precedent literature 83 species display absorption bands at 710, 820, and 920 nm in the UV−Vis spectra, which are features of transiently generated zinc−porphyrin compounds with reduced ligands 81,86 . Upon exposure of the reduced PorZn species to air, the rapid PorZn renaissance was reported in the UV−Vis spectroscopy.…”

Section: Zn-based Metal Complex Molecular Catalystmentioning

confidence: 73%

A review on the state-of-the-art advances for CO2 electro-chemical reduction using metal complex molecular catalysts

et al. 2019

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Significantly, global warming which is caused by CO2 emission and energy shortage are global problems resulting from artificial photosynthesis because it required many functions (light harvesting, Z water, and oxidation scheme). Therefore, photocatalytic systems development for CO2 reduction is germane in this field. Metal complexes molecular catalyst have become prevalent homogeneous catalysts for carbon dioxide (CO2) photocatalytic reduction since it was initially known as CO2 reduction catalysts in the 70s and the 80s, while utmost part involved macrocyclic cobalt(II) and nickel(II) complexes. This review article presents a broad understanding on some active catalysts recently reported as a metal complex molecular catalytic schemes for CO2 reduction, alongside catalytic activity, stability, selectivity under electro-reduction, and photoreduction circumstances. The progress of in situ spectroelectrochemical methods, typically supported via theoretical calculations, helped to access this know-how by providing information which enabled researchers to acquire more in-depth perception into unveiling the catalytic reaction and mechanisms intermediates.

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“…At the same time, due to progress in the development of quantum chemical methods, calculations of the structure and electronic absorption spectra of neutral and charged forms of bacteriochlorophyll molecules and their porphyrin analogs are characterized by a high predictive power. The time dependent density functional theory (TDDFT) has been successfully applied to simulation of the spectral properties of neu tral and charged forms of tetrapyrroles and their ana logs [12][13][14][15][16][17][18]. Using the ab initio method, excited states of the anion radical form of bacteriochlorophyll were calculated [19] and a satisfactory agreement with experimental data was obtained.…”

Section: Introductionmentioning

confidence: 76%

Spectroscopic properties and the nature of reduction products of bacteriochlorophyll in solution and in the photosynthetic reaction center of Rhodobacter Sphaeroides

Ivashin

Shchupak

2012

Opt. Spectrosc.

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Using methods of density functional theory, we calculate the structure and simulate the electronic absorption spectra of the anion radical of bacteriochlorophyll and its form protonated at the keto carbonyl group in a solution and in the photosynthetic reaction center of Rhodobacter Sphaeroides. We show that, in both cases, the best agreement between the calculated and experimental data is achieved under the assump tion that the anion radical form of bacteriochlorophyll is formed. An experimentally observed large differ ence between the spectral properties of the reduced form of bacteriochlorophyll in vitro and in vivo is related to peculiarities of the environment of bacteriochlorophyll in the native system and with the fact that, in this case, the initial nuclear configuration of B A has no time to completely relax in accordance with a new elec tronic configuration during the lifetime of the state P + . Taking into account the data obtained in this work, we believe that the recently proposed model of coupling of the primary charge separation in the photosyn thetic reaction center of Rhodobacter Sphaeroides with the double proton transfer seems to be unlikely.

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Study of the structure and spectral properties of radical anions of Zn complexes of porphyrins by the method of density functional theory

Cited by 6 publications

References 17 publications

Electroreduction of CO₂ Catalyzed by a Heterogenized Zn–Porphyrin Complex with a Redox-Innocent Metal Center

Electroreduction of CO₂ Catalyzed by a Heterogenized Zn–Porphyrin Complex with a Redox-Innocent Metal Center

A review on the state-of-the-art advances for CO2 electro-chemical reduction using metal complex molecular catalysts

Spectroscopic properties and the nature of reduction products of bacteriochlorophyll in solution and in the photosynthetic reaction center of Rhodobacter Sphaeroides

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Study of the structure and spectral properties of radical anions of Zn complexes of porphyrins by the method of density functional theory

Cited by 6 publications

References 17 publications

Electroreduction of CO2 Catalyzed by a Heterogenized Zn–Porphyrin Complex with a Redox-Innocent Metal Center

Electroreduction of CO2 Catalyzed by a Heterogenized Zn–Porphyrin Complex with a Redox-Innocent Metal Center

A review on the state-of-the-art advances for CO2 electro-chemical reduction using metal complex molecular catalysts

Spectroscopic properties and the nature of reduction products of bacteriochlorophyll in solution and in the photosynthetic reaction center of Rhodobacter Sphaeroides

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Electroreduction of CO₂ Catalyzed by a Heterogenized Zn–Porphyrin Complex with a Redox-Innocent Metal Center

Electroreduction of CO₂ Catalyzed by a Heterogenized Zn–Porphyrin Complex with a Redox-Innocent Metal Center