The photochemistry of electron donor–acceptor (EDA) complexes in micellar solutions. I. The stilbene–methylviologen system

1988 ◽  
Vol 66 (7) ◽  
pp. 1552-1557 ◽  
Author(s):  
M. Hamity ◽  
R. H. Lema
Keyword(s):  
Electron Donor ◽  
Sodium Dodecyl ◽  
Reaction Scheme ◽  
Local Concentration ◽  
Micellar Solutions ◽  
Yield Value ◽  
Trans Stilbene ◽  
Donor Acceptor ◽  
Volmer Plot ◽  
Upward Curvature

The association constants for the electron donor–acceptor (EDA) complexes formed between both cis-stilbene (cS) and trans-stilbene (tS) as donors and methylviologen (MV+2) as acceptor were determined in ethanol and micellar sodium dodecyl sulfate (SDS) solutions in the range of SDS concentration 0.05–0.1 M. The values obtained in micellar solutions were much higher than those in ethanol and were heavily dependent upon SDS concentration. This effect is due to an increase in the local concentration of the reactants in the micellar pseudophase. The tS fluorescence quenching by MV+2 was also studied in the same solvent media. In ethanol, the Stern–Volmer plot was found to be linear, with quenching constant (KSV) similar to the association constant determined by the absorption method. In micellar solutions, although upward curvature of the Stern–Volmer plots was observed, a reaction scheme based on static quenching via ground state EDA complex is proposed, which explains the experimental results. Irradiation in the absorption band of the EDA complexes formed by tS or cS and MV+2 was carried out in ethanol and SDS solutions, in the absence of oxygen. Only cis–trans isomerization of cS in SDS solution was observed, with a quantum yield value of Φcis = 0.012.

The photochemistry of EDA complexes in micellar solutions. II. The stilbene–methylviologen system in the presence of oxygen

1991 ◽  
Vol 69 (1) ◽  
pp. 146-150 ◽  
Author(s):  
M. Hamity ◽  
R. H. Lema
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Key Words ◽  
Methyl Viologen ◽  
Sodium Dodecyl ◽  
Cation Radical ◽  
Reaction Scheme ◽  
Quantum Yields ◽  
Micellar Solutions ◽  
Trans Stilbene ◽  
Donor Acceptor

The photolyses of electron donor–acceptor (EDA) complexes formed between both cis-stilbene (cS) and trans-stilbene (tS) as donors and mefhylviologen (MV+2) as acceptor have been carried out in homogeneous ethanolic and in micellar sodium dodecyl sulfate (SDS) solutions, in the presence of oxygen. The stilbene loss quantum yields (Φ−S) have been determined in both media. Quantum yields were observed to be dependent upon methylviologen concentration and the acidity of media. A reaction scheme is proposed, which accounts for experimental results and can be related to the photochemistry of MV+2 and its cation radical MV•+. Key words: EDA complexes, micelles, methyl viologen, stilbene.

scholarly journals Electron donor–acceptor complexes between naphthylamines and methyl viologen in aqueous sodium dodecyl sulphate solution

1986 ◽  
Vol 64 (5) ◽  
pp. 845-848 ◽  
Author(s):  
S. G. Bertolotti ◽  
J. J. Cosa ◽  
H. E. Gsponer ◽  
M. Hamity ◽  
C. M. Previtali
Keyword(s):  
Electron Donor ◽  
Sodium Dodecyl Sulphate ◽  
Methyl Viologen ◽  
Sodium Dodecyl ◽  
Local Concentration ◽  
Detergent Concentration ◽  
Aqueous Sodium ◽  
Sds Micelles ◽  
Donor Acceptor ◽  
Experimental Values

The electron donor–acceptor (EDA) interaction between methyl viologen (MV2+) and 1-naphthylamine (1NA), 2-naphthylamine (2NA), and N,N-dimethyl-1-naphthylamine (DMA) was studied in water and in aqueous sodium dodecyl sulphate (SDS). The experimental values of the association constants in water were 8.9, 9.8, and 2.8 M−1 for 1NA, 2NA, and DMA, respectively. In the presence of SDS the observed values were very much higher and strongly dependent upon the detergent concentration. The enhancement in the interaction is due to an increase in the local concentration of the partners in the micellar pseudophase. MV2+ itself was shown to strongly interact with the micelles. A new absorption is present at the red tail of the spectrum of MV2+ in the presence of SDS micelles. An association constant of 1700 M−1 was obtained from this absorption.

Interaction between tetracyanoethylene and naphthalene in reverse micelles of AOT in n-hexane. The electron-donor properties of AOT

1996 ◽  
Vol 74 (9) ◽  
pp. 1603-1608 ◽  
Author(s):  
M. A. Biasutti ◽  
Juana J. Silber
Keyword(s):  
Electron Donor ◽  
Reverse Micelles ◽  
Formation Constants ◽  
Local Concentration ◽  
Micellar Media ◽  
Visible Spectroscopy ◽  
Donor Acceptor ◽  
Uv Visible ◽  
The Stability ◽  
Homogeneous Media

The electron donor–acceptor (EDA) interaction between TCNE and naphthalene (Naph) in n-hexane and reverse micelles of AOT in n-hexane was studied by UV–visible spectroscopy with the aim of determining the influence of the micellar media on the EDA interaction. The spectra of the mixtures of TCNE–Naph in n-hexane show two typical maxima at 418 and 534 nm, assigned to the formation of a π–π EDA complex. In the micellar media a new band is observed at 398 nm. When the spectra of TCNE in n-hexane are studied in the presence of AOT two new bands at 398 and 418 nm are detected. These bands are consistent with an EDA interaction between TCNE and AOT as n-donor. The stability constants of this interaction were calculated for AOT concentrations below the CMC and in the micellar media at different W(W = [H2O]/[AOT]). The results give evidence of the tendency of AOT to interact very strongly with electron acceptors. Moreover, in the system TCNE–Naph in the micellar media it is shown that Naph and AOT compete to form a complex with TCNE. The formation constants of the complexes of AOT–Naph in the micelle system were determined at W = 0 and 5. Despite the competition of AOT for TCNE the stability constant for the complex TCNE–Naph is higher than in homogeneous media, probably due to the high local concentration of the acceptor in the micelle. Key words: reverse micelles, aerosol-OT, tetracyanoethylene, naphthalene, electron donor–acceptor complexes.

Metal-Free Photoinduced Hydroalkylation Cascade Enabled by an Electron-Donor-Acceptor Complex

2020 ◽  
Author(s):  
José Tiago Menezes Correia ◽  
Gustavo Piva da Silva ◽  
Camila Menezes Kisukuri ◽  
Elias André ◽  
Bruno Pires ◽  
...  
Keyword(s):  
Electron Donor ◽  
Functional Group ◽  
Photoexcited Electron ◽  
One Pot ◽  
Quaternary Centers ◽  
Metal Free ◽  
Acceptor Complex ◽  
Catalyst Free ◽  
Donor Acceptor ◽  
Radical Cascade

A metal- and catalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a SET event involving a photoexcited electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and step-economical approach to the construction of diversely functionalized dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization approach is also allowed giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.

Capturing polycyclic aromatic sulfur heterocycles in electron donor–acceptor complexes

2021 ◽  
Vol 31 (3) ◽  
pp. 326-329
Author(s):  
Olga E. Eremina ◽  
Mariia V. Samodelova ◽  
Mariia V. Ferree ◽  
Tatyana N. Shekhovtsova ◽  
Irina A. Veselova
Keyword(s):  
Electron Donor ◽  
Polycyclic Aromatic Sulfur Heterocycles ◽  
Polycyclic Aromatic ◽  
Donor Acceptor ◽  
Sulfur Heterocycles
Sign in / Sign up

Export Citation Format

Share Document