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.

Arrhenius Parameter for Some Gas-phase Cycloaddition Reactions of Singlet Molecular Oxygen

1974 ◽  
Vol 52 (20) ◽  
pp. 3544-3548 ◽  
Author(s):  
R. D. Ashford ◽  
E. A. Ogryzlo
Keyword(s):  
Charge Transfer ◽  
Transition State ◽  
Gas Phase ◽  
Molecular Oxygen ◽  
Rate Constants ◽  
Arrhenius Equation ◽  
Arrhenius Parameter ◽  
Singlet Molecular Oxygen ◽  
Charge Transfer Interaction ◽  
A Charge

Rate constants have been determined for several reactions of O2(1Δg) in the gas phase, at temperatures between 300 and 550 °K. The following values were obtained when the data was fitted to the Arrhenius equation:[Formula: see text]A charge-transfer interaction in the transition-state is invoked to account for the data available for such reactions.

Fluorescence Lifetime and Quenching Rates for N,N,N′,N′-Tetramethyl-P-Phenylenediamine in the Vapor Phase

1989 ◽  
Vol 43 (8) ◽  
pp. 1406-1409 ◽  
Author(s):  
S. K. Nickle ◽  
L. A. Melton
Keyword(s):  
Vapor Phase ◽  
Fluorescence Lifetime ◽  
Ground State ◽  
Rate Constants ◽  
Quenching Rate ◽  
Electronically Excited ◽  
Visualization Systems ◽  
Fuel Evaporation ◽  
Vapor Liquid

The fluorescence lifetime of N,N,N′,N′-tetramethyl- p-phenyIenediamine (TMPD) in the vapor phase has been determined to be 3.2 ± 0.3 ns for excitation at 337 nm. The rate constants for quenching of electronically excited TMPD by ground-state TMPD, O2, and CO2 have been determined to be <1 × 10−10 cm3/s, (9.9 ± 1.0) × 10−10 cm3/s, and <4 × 10−13 cm3/s, respectively. The rate for TMPD implies that self-quenching is negligible up to pressures of at least 10 Torr. The quenching rate by oxygen is sufficiently high to ensure that use of TMPD as a quantitative marker for fuel evaporation in exciplex-based vapor/liquid visualization systems is probably not possible if significant quantities of oxygen—as would be the case in combustion environments—are present.

Spectra of the 1:1 and 3:1 solid complexes of coronene-TCNQ

1977 ◽  
Vol 55 (21) ◽  
pp. 3712-3716 ◽  
Author(s):  
Kim Doan Truong ◽  
André D. Bandrauk
Keyword(s):  
Charge Transfer ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Ground State ◽  
Electronic Absorption Spectra ◽  
Charge Transfer Band ◽  
Out Of Plane ◽  
The Individual ◽  
A Charge ◽  
Solid Complexes

Two new solid TCNQ complexes have been isolated, coronene–TCNQ 1:1 and 3:1. The infrared and electronic absorption spectra are presented for the two different stoichiometries. From these spectra we infer that the complexes are covalent in the ground state with a charge transfer band appearing at 730 nm. The out of plane vibrations of the individual molecules are noticeably perturbed upon complexation.

Collisional Deactivation Rates of N2+ (B2Σu+)

1971 ◽  
Vol 49 (8) ◽  
pp. 1268-1271 ◽  
Author(s):  
G. I. Mackay ◽  
R. E. March
Keyword(s):  
Electron Beam ◽  
Charge Transfer ◽  
Rate Constants ◽  
Electron Beam Excitation ◽  
Vibrational Levels ◽  
Most Probable Mode ◽  
Electronically Excited ◽  
State Charge ◽  
Beam Excitation

Electron beam excitation of nitrogen was utilized to produce ions in the zeroth and first vibrational levels of the B2Σu+ state. The rate constants for the collisional deactivation of electronically excited N2+, for each of N2 and NO, were determined individually for the v′ = 0 and v′ = 1 vibrational levels of the N2+(B2Σu+) state. Charge transfer is the most probable mode of deactivation.

CHAMELEON GROUND STATE AND EXCITED STATES OF EDT-TTF-IM-F4TCNQ RADICAL DYAD IN DIFFERENT ENVIRONMENTS

2012 ◽  
Vol 11 (03) ◽  
pp. 505-525 ◽  
Author(s):  
YUHUA ZHOU ◽  
KAI TAN ◽  
XIN LU
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Excited States ◽  
Ground State ◽  
Density Functional ◽  
Solvent Polarity ◽  
Functional Study ◽  
Polar Solvents ◽  
Model Calculations ◽  
A Charge

We have performed a systematic density functional study on the ground-state electronic structure and excited states of a representative D-σ-A dyad, i.e. EDT-TTF-Im-F4TCNQ π-radical, in vacuo and in different conventional solvents (toluene, THF, DMF and DMSO) by using some popular hybrid density functionals (B3LYP, M05, M05-2X, PBE0 and BMK). It has been shown that the M05 and B3LYP functionals perform the best in predicting the intramolecular charge-transfer (ICT) pertaining to both the ground state and excited states of the dyad. The amphoteric dyad is liable to solvent-promoted ICT from its EDT-TTF-Im donor (D) to F4TCNQ acceptor (A), adopting a charge-unseparated ground state D-A• in vacuo, a partially zwitterionic ground state [D-A]• in nonpolar toluene solvent, and a fully zwitterionic ground state D•+-A- in such polar solvents as THF, DMF and DMSO. Owing to its solvent-dependent chameleon ground state, excited states of the dyad in solvents also exhibit remarkable dependence on solvent polarity, as revealed by TDDFT calculations. Furthermore, cluster model calculations revealed that intermolecular charge-transfer readily occurs between the dyads, accounting for the observed zwitterionic charge state in solid state and solid-state semiconductivity.

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