A Reaction Intermediate Involved in Oxygenation of Catecholatoiron(III) Complexes with Molecular Oxygen — Relevance to Catechol Dioxygenases

2004 ◽  
Vol 33 (3) ◽  
pp. 316-317 ◽  
Author(s):  
Yutaka Hitomi ◽  
Yuichiro Tase ◽  
Masakazu Higuchi ◽  
Tsunehiro Tanaka ◽  
Takuzo Funabiki
Keyword(s):  
Molecular Oxygen ◽  
Reaction Intermediate ◽  
Catechol Dioxygenases

Cooxidation reactions of ascorbic acid

1979 ◽  
Vol 44 (10) ◽  
pp. 2893-2903 ◽  
Author(s):  
Eva Schwertnerová ◽  
Dana M. Wagnerová ◽  
Josef Vepřek-Šiška
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Salicylic Acid ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Catalytic Effect ◽  
Metal Chelates ◽  
Dihydroxybenzoic Acid ◽  
Reaction Intermediate ◽  
Kinetics Of

Catalytic oxidation of salicylic acid by molecular oxygen, induced by the oxidation of ascorbic acid, leads to the formation of a mixture of isomers of dihydroxybenzoic acid. The reaction is catalyzed by a series of metal chelates, especially Fe(II) and Co(II), the most marked catalytic effect having been found in the case of tetrasulphophthalocyanine of cobalt (CoTSP). The kinetics of the oxidation of ascorbic acid in the presence of salicylic acid was followed, and the formation of hydrogen peroxide as reaction intermediate was proved.

Interaction of Molecular Oxygen with Si(001) Surface Covered with a Chromium or Titanium Monolayer

2015 ◽  
Vol 60 (1) ◽  
pp. 46-51 ◽  
Author(s):  
I.P. Koval ◽  
◽  
Yu.A. Len ◽  
M.G. Nakhodkin ◽  
M.O. Svishevs’kyi ◽  
...  
Keyword(s):  
Molecular Oxygen

Energetic Control of Redox-Active Polymers Towards Safe Organic Bioelectronic Materials

2019 ◽  
Author(s):  
Alexander Giovannitti ◽  
Reem B. Rashid ◽  
Quentin Thiburce ◽  
Bryan D. Paulsen ◽  
Camila Cendra ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Organic Semiconductors ◽  
Side Reaction ◽  
Semiconducting Polymers ◽  
Side Reactions ◽  
Redox Active ◽  
Donor Acceptor ◽  
Electrochemical Devices ◽  
Biological Environment ◽  
Device Operation

<p>Avoiding faradaic side reactions during the operation of electrochemical devices is important to enhance the device stability, to achieve low power consumption, and to prevent the formation of reactive side‑products. This is particularly important for bioelectronic devices which are designed to operate in biological systems. While redox‑active materials based on conducting and semiconducting polymers represent an exciting class of materials for bioelectronic devices, they are susceptible to electrochemical side‑reactions with molecular oxygen during device operation. We show that this electrochemical side reaction yields hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), a reactive side‑product, which may be harmful to the local biological environment and may also accelerate device degradation. We report a design strategy for the development of redox-active organic semiconductors based on donor-acceptor copolymers that prevent the formation of H<sub>2</sub>O<sub>2</sub> during device operation. This study elucidates the previously overlooked side-reactions between redox-active conjugated polymers and molecular oxygen in electrochemical devices for bioelectronics, which is critical for the operation of electrolyte‑gated devices in application-relevant environments.</p>

Optical Properties of Photodynamic Therapy Drugs in Different Environments: The Paradigmatic Case of Temoporfin

2020 ◽  
Author(s):  
busenur Aslanoglu ◽  
Ilya Yakavets ◽  
Vladimir Zorin ◽  
Henri-Pierre Lassalle ◽  
Francesca Ingrosso ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Optical Properties ◽  
Photodynamic Therapy ◽  
Minimally Invasive ◽  
Visible Light ◽  
Cancer Treatment ◽  
Singlet Oxygen ◽  
Tumor Cells ◽  
Molecular Oxygen ◽  
Computational Tools

Computational tools have been used to study the photophysical and photochemical features of photosensitizers in photodynamic therapy (PDT) –a minimally invasive, less aggressive alternative for cancer treatment. PDT is mainly based by the activation of molecular oxygen through the action of a photoexcited sensitizer (photosensitizer). Temoporfin, widely known as mTHPC, is a second-generation photosensitizer, which produces the cytotoxic singlet oxygen when irradiated with visible light and hence destroys tumor cells. However, the bioavailability of the mostly hydrophobic photosensitizer, and hence its incorporation into the cells, is fundamental to achieve the desired effect on malignant tissues by PDT. In this study, we focus on the optical properties of the temoporfin chromophore in different environments –in <i>vacuo</i>, in solution, encapsulated in drug delivery agents, namely cyclodextrin, and interacting with a lipid bilayer.

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