Photosensitized oxidation of 9,10-dimethylanthracene with singlet oxygen by using a safranin O/silica composite under visible light

The rate of the methylene blue photosensitized oxidation of olefins increases in the order: 1-nonene < 4-methylcyclohexene < cyclohexene < 2,3-dimethyl-1-butene < 2-hexene < cyclopentene < 1-methylcyclohexene < 2,3-dimethylcyclohexene < 1-methylcyclopentene < 1,2-dimethylcyclohexene < 2,3-dimethyl-2-butene. The last compound is oxidized 5 500 times as fast as cyclohexene. Comparison of this reactivity sequence with those obtained in other reactions confirms that the reactive intermediate in the photosensitized oxidations is electrophilic. The relative rates (kA/kB) of photo-oxidation of 1-methylcyclopentene (A) and of 1-methylcyclohexene (B) are 10 and do not vary significantly with five different sensitizers. Thus the same reactive intermediate, presumably singlet oxygen, is formed using each of the five sensitizers.

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Visible-Light Triggered Templated Ligation on Surface Using Furan-Modified PNAs

10.26434/chemrxiv.12974246.v1 ◽

2020 ◽

Author(s):

Alex Manicardi ◽

Enrico Cadoni ◽

Annemieke Madder

Keyword(s):

Nucleic Acid ◽

Visible Light ◽

Singlet Oxygen ◽

Target Detection ◽

High Throughput ◽

White Light ◽

Peptide Nucleic Acids ◽

Photo Oxidation ◽

Reducing Conditions ◽

Furan Moiety

Oligonucleotide-templated reactions are frequently exploited for target detection in biosensors and for the construction of DNA-based materials and probes in nanotechnology. Translation of the specifically used template chemistry from solution to surfaces, with the final aim of achieving highly selective high-throughput systems, has been difficult to reach and poorly explored. Here, we show the first example of a visible light-triggered templated ligation on a surface, employing furan-modified peptide nucleic acids (PNAs). Tailored photo-oxidation of the pro-reactive furan moiety is ensured by the simultaneous introduction of a weak photosensitizer as well as a nucleophilic moiety in the reacting PNA strand. This allows a localized production of singlet oxygen for furan activation, which is not affected by probe dilution or reducing conditions. White light irradiation in combination with recognition of a short 22mer oligo sequence that functions as a template, allows sensitive detection of nucleic acid targets in a 96 well plate format.

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On the Involvement of Singlet Oxygen in the Biosynthesis of Oxygenation Products of the Furocoumarin Imperatorine

Zeitschrift für Naturforschung B ◽

10.1515/znb-1984-1022 ◽

1984 ◽

Vol 39 (10) ◽

pp. 1433-1441 ◽

Cited By ~ 5

Author(s):

Nicolaas J. de Mol ◽

Johannes Reisch ◽

Gerardus M. J. Beijersbergen van Henegouwen

Keyword(s):

Methylene Blue ◽

Visible Light ◽

Protective Effect ◽

Singlet Oxygen ◽

Oxidation Products ◽

Photo Oxidation ◽

Uva Light ◽

Β Carotene

The role of singlet oxygen (1O2) in the photo-oxidation of the furocoumarin im peratorine was investigated in vitro. Irradiation with visible light and sensitization with methylene blue yielded the imperatorine oxidation product isogosferol and the corresponding ketone as main products. The involvement of 1O2 was dem onstrated by studying the rate of oxidation under conditions that affect the lifetime of 1O2. Com pared to a range of other furocoumarins, im peratorine appeared to be moderately active as a 1O2 generator. The extent of 1O2 production correlated with the skin sensitizing activity. Upon irradiation of im peratorine itself with UVA light (360 nm) no isogosferol formation is observed, probably as a consequence of its photochemical instability. Irradiation with visible light (λ > 400 nm) of a chlorophyll chromophore containing sensitizer in the presence of imperatorine, yielded isogosferol and the corresponding ketone product. This dem onstrates that in the formation of 1O2 oxidation products of imperatorine in plants naturally occuring sensitizers e.g. chlorophyll and visible light are involved, rather than 1O2 produced by im peratorine or other furocoumarins and UVA light. The protective effect on the chlorophyll sensitized im peratorine oxidation by the 1O2- and chlorophyll triplet quencher β-carotene was demonstrated in a lipophilic solvent.

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meso-Carbazole substituted palladium porphyrins: Efficient catalysts for visible light induced oxidation of aldehydes

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424621500486 ◽

2021 ◽

pp. A-K

Author(s):

Anu Janaagal ◽

Vijayalakshmi Pandey ◽

Sudhir Sabharwal ◽

Iti Gupta

Keyword(s):

Visible Light ◽

Singlet Oxygen ◽

Aerobic Oxidation ◽

Aromatic Aldehydes ◽

Palladium Complexes ◽

Light Irradiation ◽

Quantum Yields ◽

Oxidation Reactions ◽

Photo Oxidation ◽

Catalytic Application

The A3B and A2B2 type porphyrins having [Formula: see text]-butylcarbazole and [Formula: see text]-cyanophenyl groups are synthesized and characterized. Their palladium complexes have also been prepared and utilized as catalysts for the photo-oxidation reactions of aromatic aldehydes in good yields. Pd(II)porphyrins displayed decent phosphorescence at [Formula: see text]670 nm and were able to generate singlet oxygen upon light irradiation. The calculated singlet oxygen quantum yields for Pd(II)porphyrins were between 57% and 73%. The photo-catalytic application of Pd(II)porphyrins for aerobic oxidation of aromatic aldehydes is demonstrated.

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Visible-Light Triggered Templated Ligation on Surface Using Furan-Modified PNAs

10.26434/chemrxiv.12974246 ◽

2020 ◽

Author(s):

Alex Manicardi ◽

Enrico Cadoni ◽

Annemieke Madder

Keyword(s):

Nucleic Acid ◽

Visible Light ◽

Singlet Oxygen ◽

Target Detection ◽

High Throughput ◽

White Light ◽

Peptide Nucleic Acids ◽

Photo Oxidation ◽

Reducing Conditions ◽

Furan Moiety

Oligonucleotide-templated reactions are frequently exploited for target detection in biosensors and for the construction of DNA-based materials and probes in nanotechnology. Translation of the specifically used template chemistry from solution to surfaces, with the final aim of achieving highly selective high-throughput systems, has been difficult to reach and poorly explored. Here, we show the first example of a visible light-triggered templated ligation on a surface, employing furan-modified peptide nucleic acids (PNAs). Tailored photo-oxidation of the pro-reactive furan moiety is ensured by the simultaneous introduction of a weak photosensitizer as well as a nucleophilic moiety in the reacting PNA strand. This allows a localized production of singlet oxygen for furan activation, which is not affected by probe dilution or reducing conditions. White light irradiation in combination with recognition of a short 22mer oligo sequence that functions as a template, allows sensitive detection of nucleic acid targets in a 96 well plate format.

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Users behaviors: The Heritage of Digital World

INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY ◽

10.24297/ijct.v13i7.2512 ◽

2014 ◽

Vol 13 (7) ◽

pp. 4675-4682

Author(s):

Atefeh Danesh Moghadam ◽

Alireza Alagha

Keyword(s):

Technology Development ◽

Second Step ◽

Information Communication ◽

The Third ◽

Digital World ◽

New Concepts ◽

Emerging Patterns ◽

History Of ◽

Fourth Step ◽

Communication And Technology

In the advent of information era, not only digital world is going to expand its territories, it is going to penetrate into the traditional notions about the meaning of the words and also valorize new concepts. According to Oxford Dictionary, the word heritage is defined: The history, tradition and qualities that a country or society has had for many years and that are considered an important part of its character. In order to present how emerging patterns, as the consequences of technology development, are going to be considered as the new concept of heritage, we follow four steps. In the first step, we present the convergence of Information, Communication and Technology (ICT) and a concise history of its convergence. In the second step, we argue how convergence has culminated in emerging patterns and also has made changes in digital world. In the third step, the importance of users behaviors and its mining is surveyed. Finally, in the fourth step; we illustrate User Generated Contents (UGC) as the most prominent users behaviors in digital world.

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

10.26434/chemrxiv.12118917.v2 ◽

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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The Kinney Three Paragraphs (and More) for Accounting Ph.D. Students

Accounting Horizons ◽

10.2308/acch-52451 ◽

2019 ◽

Vol 33 (4) ◽

pp. 1-14 ◽

Cited By ~ 9

Author(s):

William R. Kinney

Keyword(s):

Review Process ◽

Student Experiences ◽

Second Step ◽

Practical Relevance ◽

The Third ◽

Validity Assessment ◽

Essential Components ◽

Potential Problems ◽

Empirical Accounting Research

SYNOPSIS This Commentary is intended to help beginning Ph.D. students identify, evaluate, and communicate essential components of proposed empirical accounting research using a three-step process. The first step is a structured top-down approach of writing answers to three related questions—What, Why, How—that emphasize the central role of conceptual thinking in research design, as well as practical relevance. The second step is a predictive validity assessment that anticipates concerns likely to arise in the scholarly review process, and the third is consideration of the likely outcome and potential problems to be encountered if the proposal is implemented as planned. First-hand accounts of Ph.D. student experiences using the three paragraphs and three-step approach are presented, along with an exercise that beginners can use to help themselves identify, analyze, and anticipate problems to improve chances for research success ex ante.

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