Photoaddition of α-diketones to olefins. Stereospecificity of the addition reaction

1970 ◽  
Vol 48 (19) ◽  
pp. 3045-3052 ◽  
Author(s):  
Y. L. Chow ◽  
T. C. Joseph ◽  
H. H. Quon ◽  
J. N. S. Tam
Keyword(s):  
Charge Transfer ◽  
Addition Reaction ◽  
Reactive Species ◽  
Large Excess ◽  
Transfer Structure ◽  
A Charge ◽  
Cis And Trans

Phenanthraquinone (PQ) photolytically adds to cis- and trans-alkenes to give a mixture of cis- and trans-1,4-dioxenes and two reduction products. The ratios of cis- to trans- 1,4-dioxenes remain the same irrespective of the photoaddition to cis- or trans-alkenes and are 1:1 for 2-butenes, 6:4 for 3-hexenes, and 8:2 for cyclohexene. A triplet excited phenanthraquinone is proposed as the reactive species which initiates the addition leading to the intermediate diradical 10. Depending on the nature of addenda the diradical 10 may be stabilized by a charge transfer structure in different conformations leading to the observed stereochemistry of the adducts. The PQ fails to add to fumaronitrile photolytically or thermally and thermally adds to 2-butenes only inefficiently. Biacetyl undergoes photoreduction readily in the presence of a large excess of cyclohexene.

Determination of Epsilon Aminocaproic Acid Based on Charge Transfer Complexation with p-Nitrophenlol by Spectrophotometry

2020 ◽  
Vol 16 ◽  
Author(s):  
Sheng-Yun Li ◽  
Fang Tian
Keyword(s):  
Charge Transfer ◽  
Aminocaproic Acid ◽  
Concentration Limit ◽  
Official Method ◽  
Good Precision ◽  
Pharmaceutical Dosage Forms ◽  
Relative Standard ◽  
A Charge ◽  
Epsilon Aminocaproic Acid

: A spectrophotometry was investigated for the determination of epsilon aminocaproic acid (EACA) with p-nitrophenol (PNP). The method was based on a charge transfer (CT) complexation of this drug as n-electron donor with π-acceptor PNP. Experiment indicated that the CT complexation was carried out at room temperature for 10 minutes in dimethyl sulfoxide solvent. The spectrum obtained for EACA/PNP system showed the maximum absorption band at wavelength of 425 nm. The stoichiometry of the CT complex was found to be 1:1 ratio by Job’s method between the donor and the acceptor. Different variables affecting the complexation were carefully studied and optimized. At the optimum reaction conditions, Beer’s law was obeyed in a concentration limit of 1～6 µg mL-1. The relative standard deviation was less than 2.9%. The apparent molar absoptivity was determined to be 1.86×104 L mol-1cm-1 at 425 nm. The CT complexation was also confirmed by both FTIR and 1H NMR measurements. The thermodynamic properties and reaction mechanism of the CT complexation have been discussed. The developed method could be applied successfully for the determination of the studied compound in its pharmaceutical dosage forms with a good precision and accuracy compared to official method as revealed by t- and F-tests.

Fluorescence Quenching of Aminodiphenylamines with Chloromethanes

2002 ◽  
Vol 67 (8) ◽  
pp. 1154-1164 ◽  
Author(s):  
Nachiappan Radha ◽  
Meenakshisundaram Swaminathan
Keyword(s):  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Ground State ◽  
Rate Constants ◽  
Quenching Mechanism ◽  
Quenching Rate ◽  
Charge Transfer Interaction ◽  
Electronically Excited ◽  
A Charge

The fluorescence quenching of 2-aminodiphenylamine (2ADPA), 4-aminodiphenylamine (4ADPA) and 4,4'-diaminodiphenylamine (DADPA) with tetrachloromethane, chloroform and dichloromethane have been studied in hexane, dioxane, acetonitrile and methanol as solvents. The quenching rate constants for the process have also been obtained by measuring the lifetimes of the fluorophores. The quenching was found to be dynamic in all cases. For 2ADPA and 4ADPA, the quenching rate constants of CCl4 and CHCl3 depend on the viscosity, whereas in the case of CH2Cl2, kq depends on polarity. The quenching rate constants for DADPA with CCl4 are viscosity-dependent but the quenching with CHCl3 and CH2Cl2 depends on the polarity of the solvents. From the results, the quenching mechanism is explained by the formation of a non-emissive complex involving a charge-transfer interaction between the electronically excited fluorophores and ground-state chloromethanes.

Charge-transfer induced multifunctional BCP:Ag complexes for semi-transparent perovskite solar cells with a record fill factor of 80.1%

2021 ◽  
Author(s):  
Zhiqin Ying ◽  
Xi Yang ◽  
Jingming Zheng ◽  
Yudong Zhu ◽  
Jingwei Xiu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Buffer Layer ◽  
Fill Factor ◽  
Perovskite Solar Cells ◽  
A Charge

A charge-transfer induced BCP:Ag complex is employed as a multifunctional buffer layer for efficient inverted semi-transparent perovskite solar cells.

scholarly journals Multi-configurational Ehrenfest simulations of ultrafast nonadiabatic dynamics in a charge-transfer complex

2018 ◽  
Vol 149 (24) ◽  
pp. 244107 ◽  
Author(s):  
Tianji Ma ◽  
Matteo Bonfanti ◽  
Pierre Eisenbrandt ◽  
Rocco Martinazzo ◽  
Irene Burghardt
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complex ◽  
Nonadiabatic Dynamics ◽  
A Charge

scholarly journals Synthesis and Photobehavior of a NewDehydrobenzoannulene-Based HOF with Fluorine Atoms: From Solution to Single Crystals Observation

2021 ◽  
Vol 22 (9) ◽  
pp. 4803
Author(s):  
Eduardo Gomez ◽  
Ichiro Hisaki ◽  
Abderrazzak Douhal
Keyword(s):  
Charge Transfer ◽  
Single Crystals ◽  
Parent Compound ◽  
Time Resolved ◽  
Strong Basis ◽  
Triplet Structure ◽  
Carboxylic Groups ◽  
Potential Applications ◽  
A Charge ◽  
Further Development

Hydrogen-bonded organic frameworks (HOFs) are the focus of intense scientific research due their potential applications in science and technology. Here, we report on the synthesis, characterization, and photobehavior of a new HOF (T12F-1(124TCB)) based on a dehydrobenzoannulene derivative containing fluorine atoms (T12F-COOH). This HOF exhibits a 2D porous sheet, which is hexagonally networked via H-bonds between the carboxylic groups, and has an interlayers distance (4.3 Å) that is longer than that of a typical π–π interaction. The presence of the fluorine atoms in the DBA molecular units largely increases the emission quantum yield in DMF (0.33, T12F-COOH) when compared to the parent compound (0.02, T12-COOH). The time-resolved dynamics of T12F-COOH in DMF is governed by the emission from a locally excited state (S1, ~ 0.4 ns), a charge-transfer state (S1(CT), ~ 2 ns), and a room temperature emissive triplet state (T1, ~ 20 ns), in addition to a non-emissive triplet structure with a charge-transfer character (T1(CT), τ = 0.75 µs). We also report on the results using T12F-ester. Interestingly, FLIM experiments on single crystals unravel that the emission lifetimes of the crystalline HOF are almost twice those of the amorphous ones or the solid T12F-ester sample. This shows the relevance of the H-bonds in the photodynamics of the HOF and provides a strong basis for further development and study of HOFs based on DBAs for potential applications in photonics.

The Reagent Diphenyldiselane/Iodine: No Phenylselenenyl Iodide but a Charge Transfer Complex with Cyclic Moieties

1988 ◽  
Vol 27 (3) ◽  
pp. 431-433 ◽  
Author(s):  
Silvia Kubiniok ◽  
Wolf-Walther du Mont ◽  
Siegfried Pohl ◽  
Wolfgang Saak
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complex ◽  
A Charge
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