Catalytic control of electron-transfer processes

Fukuzumi, Shunichi

doi:10.1351/pac200375050577

Cited by 33 publications

(17 citation statements)

References 26 publications

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“…Redox-inactive metal ions can both act as a Lewis acid and play a pivotal role in promoting various reactions [ 44 ]. Previous studies have shown that the binding of ionic metal species with radical anions plays an important role in mediating the electron-transfer reactivity of the substrate [ 45 ]. The complexation of

to metal ions can be achieved by photo-induced electron transfer from the excited state of a dimeric organic compound, in which the catalytic process acts as a unique two-electron donor and then yields two monomeric cations along with two

–metal ion complex radical ions [ 44 , 46 ].…”

Section: Discussionmentioning

confidence: 99%

Catechin Photolysis Suppression by Aluminum Chloride under Alkaline Conditions and Assessment with Liquid Chromatography–Mass Spectrometry

et al. 2020

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Tea is rich in catechins and aluminum. In this study, the process of catechin photolysis was applied as a model for examining the effects of aluminum chloride (AlCl3) on the structural changes of catechin and the alteration of aluminum complexes under blue light irradiation (BLI) at pH 8 using liquid chromatography and mass spectrometry techniques. Additionally, the effects of anions on catechin upon the addition of AlCl3 and treatment with BLI were also studied. In this study, when 1 mM catechin was treated with BLI, a superoxide anion radical (O2•−) was generated in an air-saturated aqueous solution, in addition to forming a dimeric catechin (proanthocyanidin) via a photon-induced redox reaction. The relative percentage of catechin was found to be 59.0 and 95.7 for catechin treated with BLI and catechin upon the addition of 1 mM AlCl3 treated with BLI, respectively. It suggested that catechin treated with BLI could be suppressed by AlCl3, while AlCl3 did not form a complex with catechin in the photolytic system. However, under the same conditions, it was also found that the addition of AlCl3 inhibited the photolytic formation of O2•−, and reduced the generation of proanthocyanidin, suggesting that the disconnection of proanthocyanidin was achieved by AlCl3 acting as a catalyst under treatment with BLI. The influence of 1 mM fluoride (F−) and 1 mM oxalate (C2O42−) ions on the photolysis of 1 mM catechin upon the addition of 1 mM AlCl3 and treatment with BLI was found to be insignificant, implying that, during the photolysis of catechin, the Al species were either neutral or negatively charged and the aluminum species did not form a complex with anions in the photolytic system. Therefore, aluminum, which is an amphoteric species, has an inherent potential to stabilize the photolysis of catechin in an alkaline conditions, while suppressing the O2•− and proanthocyanidin generation via aluminum ion catalysis in the catechin/Al system under treatment with BLI.

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–metal ion complex radical ions [ 44 , 46 ].…”

Section: Discussionmentioning

confidence: 99%

Catechin Photolysis Suppression by Aluminum Chloride under Alkaline Conditions and Assessment with Liquid Chromatography–Mass Spectrometry

et al. 2020

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“…This review focuses on acid catalysis of both Brønsted acids and metal ions acting as Lewis acids by binding these acids to A to accelerate ET reactions from D to A. [32][33][34][35][36][37][38][39][40][41][42] The fundamental concept of acid catalysis in ET chemistry is shown in Scheme In the presence of a Lewis acid (LA: H + or metal ions), a LA binds to a base (A •-) to produce A •--LA. Because of the strong binding in A •--LA, ET from D to A becomes exergonic to produce D •+ and A •--LA, [32][33][34][35][36][37][38][39][40][41][42] followed by C C bond formation to produce D-A after releasing LA.…”

Section: Introductionmentioning

confidence: 99%

Acid Catalysis via Acid‐Promoted Electron Transfer

Fukuzumi

Lee

Nam

2020

Bulletin Korean Chem Soc

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This feature article focuses on acid catalysis in various redox reactions of not only organic compounds but also metal complexes, in particular metal-oxygen complexes via acid-promoted electron transfer (APET). On the other hand, proton-coupled electron transfer (PCET) has been extensively studied in relation with important biological PCET reactions such as O 2 reduction in respiration and water oxidation in photosynthesis. Because PCET is normally defined as simultaneous electron and proton transfer from the same substrate, acid-promoted electron transfer using external acids is called APET in this article. Various types of chemical transformations exhibiting acid catalysis via APET discussed in this article include C C bond formation, C H bond oxidation, aromatic hydroxylation, and oxygen atom transfer reactions such as sulfoxidation and epoxidation reactions.

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“…They are readily synthesized, and their properties are easily tuned by substitution and metalation. In addition, the aggregated state guarantees increased absorption cross-sections and an efficient use of the solar spectrum for energy conversion [24][25][26]. Based on the above concept, numerous reports have appeared discussing photoinduced charge separation and light energy conversion in porphyrin-CNT and porphyrin-fullerene assemblies, so far [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Molecular nanoarchitectures composed of porphyrins and carbon nanomaterials for light energy conversion

Hasobe

Sakai

2011

J. Porphyrins Phthalocyanines

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In this review, we report the recent advances in the construction of composite molecular nanoarchitectures of porphyrins and nanoscale carbon materials such carbon nanotubes (CNT), graphenes and polycyclic aromatic hydrocarbons (PAH) for photoinduced electron transfer and light energy conversion. First, we state novel single-wall carbon nanotubes (SWCNT)-driven aggregation of protonated porphyrins to produce supramolecular assemblies in the form of macroscopic bundles. Then, photoinduced electron transfer in self-assembled single-walled carbon nanotube (SWCNT)/ zinc porphyrin (ZnP) hybrids utilizing (7,6)-and (6,5)-enriched SWCNTs having different band gaps is reported. Further, we discuss the structural and photoelectrochemical properties of porphyrin-based molecular assemblies of other carbon materials such as stacked-cup carbon nanotubes (SCCNT), carbon nanohorns (CNH) and graphenes. Finally, novel supramolecular patterning formation composed of triphenylene core-centered porphyrin hexamers for electronics is discussed.

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Catalytic control of electron-transfer processes

Cited by 33 publications

References 26 publications

Catechin Photolysis Suppression by Aluminum Chloride under Alkaline Conditions and Assessment with Liquid Chromatography–Mass Spectrometry

Catechin Photolysis Suppression by Aluminum Chloride under Alkaline Conditions and Assessment with Liquid Chromatography–Mass Spectrometry

Acid Catalysis via Acid‐Promoted Electron Transfer

Molecular nanoarchitectures composed of porphyrins and carbon nanomaterials for light energy conversion

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