84-58-2Relevant articles and documents
Electron self-exchange kinetics between 2,3-dicyano-5,6-dichloro-p-benzoquinone (DDQ) and its radical anion. Part 1. Solvent dynamical effects
Grampp, Guenter,Landgraf, Stephan,Rasmussen, Kjeld
, p. 1897 - 1899 (1999)
Rate constants of the electron self-exchange between 2,3-dicyano-5,6-dichloro-p-benzoquinone (DDQ) and its radical anion (DDQ.-) are measured by means of EPR-line-broadening effects in different solvents at T = 293 K. Solvents of different polarity like CHCl3, CH2Cl2, CH3CN, benzonitrile and acetone were used. No correlation is found in the sense of the classical Marcus theory, where In ket should depend linearly on the solvent parameter γ = 1/n2-1/εs (n = refractive index, εs = static relative permittivity of the solvent). The investigated γ-range was 0.270 ≤ γ ≤ 0.530. The diffusion corrected rate constants ket cover a range of 8.9 to 36.7 × 108 M-1 s-1 and clearly show a solvent-dynamical effect, expressed by the longitudinal relaxation time τL dependence of the solvents used. The observed dynamical friction solvent effects clearly indicate an adiabatic reaction behaviour of this electron self-exchange reaction.
Electronic, infrared, mass spectrometry and thermal studies on the reaction of 2-amino-6-methylpyridine with π-acceptors
Madrahimov, Sherzod,Mostafa, Adel,Yempally, Veeranna,Fadlallah, Joelle,AlQaradawi, Siham Y.
, (2019/09/10)
The spectrophotometric characteristics of the solid charge-transfer molecular complexes (CT) formed in the reaction of the electron donor 2-amino-6-methylpyridine (2A6MPy) with the π-acceptors tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-1,4-benzoq
Spectroscopic and thermal investigations on the charge transfer interaction between risperidone as a schizophrenia drug with some traditional π-acceptors: Part 2
El-Habeeb, Abeer A.,Al-Saif, Foziah A.,Refat, Moamen S.
, p. 464 - 477 (2013/04/23)
The focus of present investigation was to assess the utility of non-expensive techniques in the evaluation of risperidone (Ris) in solid and solution states with different traditional π-acceptors and subsequent incorporation of the analytical determination into pharmaceutical formulation for a faster release of risperidone. Charge-transfer complexes (CTC) of risperidone with picric acid (PA), 2,3-dichloro-5,6-dicyano-p-benzoquinon (DDQ), tetracyanoquinodimethane (TCNQ), tetracyano ethylene (TCNE), tetrabromo-p-quinon (BL) and tetrachloro-p-quinon (CL) have been studied spectrophotometrically in absolute methanol at room temperature. The stoichiometries of the complexes were found to be 1:1 ratio by the photometric molar ratio between risperidone and the π-acceptors. The equilibrium constants, molar extinction coefficient (εCT) and spectroscopic-physical parameters (standard free energy (ΔGo), oscillator strength (f), transition dipole moment (μ), resonance energy (RN) and ionization potential (ID)) of the complexes were determined upon the modified Benesi-Hildebrand equation. Risperidone in pure form was applied in this study. The results indicate that the formation constants for the complexes depend on the nature of electron acceptors and donor, and also the spectral studies of the complexes were determined by (infrared, Raman, and 1H NMR) spectra and X-ray powder diffraction (XRD). The most stable mono-protonated form of Ris is characterized by the formation of +NH (pyrimidine ring) intramolecular hydrogen bonded. In the high-wavenumber spectral region ～3400 cm-1, the bands of the +NH stretching vibrations and of the pyrimidine nitrogen atom could be potentially useful to discriminate the investigated forms of Ris. The infrared spectra of both Ris complexes are confirming the participation of +NH pyrimidine ring in the donor-acceptor interaction.
Anion radical formation in the reaction of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) with tribenzylamine in acetonitrile
Dworniczak,Jarczewski
, p. 1739 - 1743 (2007/10/03)
Kinetics of the reaction of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) with tribenzylamine in acetonitrile has been measured spectrophotometrically. The product of this reaction is a stable anion radical of DDQ. The reaction is relatively slow, due to a considerable steric hindrance in both quinone and amine molecule. Activation parameters indicate a charge separation in the transition state. The mechanism of the reaction has been proposed.
