Photochemical Reactions between C60and Aromatic Thiols. Protonation of C60via Photoinduced Electron Transfer

1998 ◽  
Vol 102 (38) ◽  
pp. 7447-7451 ◽  
Author(s):  
Maksudul M. Alam ◽  
Masahiro Sato ◽  
Akira Watanabe ◽  
Takeshi Akasaka ◽  
Osamu Ito
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Photochemical Reactions ◽  
Aromatic Thiols

Article

1999 ◽  
Vol 77 (10) ◽  
pp. 1655-1670 ◽  
Author(s):  
Dino Mangion ◽  
Donald R Arnold
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Photochemical Reactions ◽  
Transfer Mechanism ◽  
Radical Ions ◽  
Reaction Conditions ◽  
Electron Transfer Mechanism ◽  
Photochemical Reactivity ◽  
Bond Homolysis

The photochemical reactivity of a series of 4-halobenzonitriles and 4-haloanisoles with 1,1-diphenylethene in a nucleophilic solvent (methanol) has been investigated. Analysis of the photochemical reactions involving the 4-halobenzonitriles revealed formation of alkene-methanol adducts, such as 1-methoxy-2,2-diphenylethane, 1-methoxy-2,2-diphenylethene, and 1,1-dimethoxy-2,2-diphenylethane, indicative of a photochemical electron-transfer mechanism. These products were not significant in the photochemical reactions involving the 4-haloanisoles. Both the 4-halobenzonitriles and the 4-haloanisoles produced an arene-alkene-methanol Markovnikov adduct, 1-aryl-2-methoxy-2,2-diphenylethane (aryl = 4-cyanophenyl or 4-methoxyphenyl). This compound was shown to undergo an acid-catalysed elimination to 1-aryl-2,2-diphenylethene under the reaction conditions, which subsequently underwent a 6pi-electrocyclization to the 3-substituted(cyano or methoxy)-9-phenylphenanthrene. Possible mechanisms for the observed reactivity are discussed and evaluated.Key words: photochemistry, photoinduced electron transfer, bond homolysis, radical ions, radicals, exciplexes.

scholarly journals Environment-friendly organic synthesis. The photochemical approach

2000 ◽  
Vol 72 (7) ◽  
pp. 1321-1326 ◽  
Author(s):  
Angelo Albini ◽  
Maurizio Fagnoni ◽  
Mariella Mella
Keyword(s):  
Electron Transfer ◽  
Organic Synthesis ◽  
Photoinduced Electron Transfer ◽  
Photochemical Reactions ◽  
Environment Friendly

Photochemical reactions are expected to have an increasing role in organic synthesis with the drive towards environment-friendly reactions. Some examples illustrating the scope and versatility of radical alkylation of electrophilic alkenes via photoinduced electron transfer are presented. A few applications in special fields are mentioned.

Products from photochemical reactions and electrochemical oxidation of methylenecyclopropane

1997 ◽  
Vol 75 (12) ◽  
pp. 1795-1809 ◽  
Author(s):  
H.J.P. de Lijser ◽  
T. Stanley Cameron ◽  
Donald R. Arnold
Keyword(s):  
Electron Transfer ◽  
Ionization Potential ◽  
Radical Cation ◽  
Photoinduced Electron Transfer ◽  
Nucleophilic Addition ◽  
Major Product ◽  
Oxidation Potential ◽  
Photochemical Reactions ◽  
Tert Butyl ◽  
Adiabatic Ionization Potential

The reactivity of methylenecyclopropane (MCP, 1) and its radical cation (1+•) have been studied in the presence and absence of a nucleophile (methanol). Photochemical reactions of 1 in the presence of an electron-acceptor (1,4-dicyanobenzene, 6) and a codonor (biphenyl, 7) in acetonitrile (with and without methanol present) or chloroform lead to cycloadditions (ortho, meta, and para; products 12–17) rather than products from photoinduced electron transfer (PET). Based on the measured (cyclic voltammetry, CV) oxidation potential, using the Weller equation, electron transfer (ET) was predicted to occur. It was shown that the measured oxidation potential of 1 represents the adiabatic ionization potential. For PET processes the value for the vertical ionization potential must be used. Electrochemical (EC) generation of 1+• without a nucleophile present results in the formation of one major product: tert-butyl acetamide (25). A series of rearrangements leading to the tert-butyl cation is proposed. Addition of a nucleophile (methanol) to the mixture leads to the formation of 3-methoxy-2-(methoxymethyl)-1-propene (26). This product may arise from trapping of the initially formed ring-opened (trimethylenemethane) radical cation (1a+•), which undergoes a second oxidation and nucleophilic addition (ECE). Keywords: methylenecyclopropane, radical cation, photochemistry, electrochemistry, photocycloaddition.

Photochemical Reactions of Coenzyme PQQ (Pyrroloquinolinequinone) and Analogues with Benzyl Alcohol Derivatives via Photoinduced Electron Transfer

2000 ◽  
Vol 122 (35) ◽  
pp. 8435-8443 ◽  
Author(s):  
Shunichi Fukuzumi ◽  
Shinobu Itoh ◽  
Takashi Komori ◽  
Tomoyoshi Suenobu ◽  
Akito Ishida ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Benzyl Alcohol ◽  
Photoinduced Electron Transfer ◽  
Photochemical Reactions

Enhanced Reactivity of C70in the Photochemical Reactions with NADH and NAD Dimer Analogues As Compared to C60via Photoinduced Electron Transfer

1999 ◽  
Vol 103 (30) ◽  
pp. 5935-5941 ◽  
Author(s):  
Shunichi Fukuzumi ◽  
Tomoyoshi Suenobu ◽  
Takeomi Hirasaka ◽  
Norio Sakurada ◽  
Ryuichi Arakawa ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Photochemical Reactions

Computationally Assisted Design of High Signal-to-Noise Photoinduced Electron Transfer-Based Voltage-Sensitive Dyes

2020 ◽  
Author(s):  
Rishikesh Kulkarni ◽  
Anneliese Gest ◽  
Chun Kei Lam ◽  
Benjamin Raliski ◽  
Feroz James ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dft Calculations ◽  
Photoinduced Electron Transfer ◽  
Density Functional ◽  
Embryonic Stem ◽  
High Sensitivity ◽  
Md Simulations ◽  
High Signal ◽  
Signal To Noise ◽  
Green Fluorescent

<p>High signal-to-noise optical voltage indicators will enable simultaneous interrogation of membrane potential in large ensembles of neurons. However, design principles for voltage sensors with high sensitivity and brightness remain elusive, limiting the applicability of voltage imaging. In this paper, we use molecular dynamics (MD) simulations and density functional theory (DFT) calculations to guide the design of a bright and sensitive green-fluorescent voltage-sensitive fluorophore, or VoltageFluor (VF dye), that uses photoinduced electron transfer (PeT) as a voltage-sensing mechanism. MD simulations predict an 11% increase in sensitivity due to membrane orientation, while DFT calculations predict an increase in fluorescence quantum yield, but a decrease in sensitivity due to a decrease in rate of PeT. We confirm these predictions by synthesizing a new VF dye and demonstrating that it displays the expected improvements by doubling the brightness and retaining similar sensitivity to prior VF dyes. Combining theoretical predictions and experimental validation has resulted in the synthesis of the highest signal-to-noise green VF dye to date. We use this new voltage indicator to monitor the electrophysiological maturation of human embryonic stem cell-derived medium spiny neurons. </p>

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