1518-16-7Relevant articles and documents
Photoinduced charge-separation using 10-methylacridinium ion loaded in zeolite Y as a photocatalyst with negligible back electron transfer across the zeolite-solution interface
Fukuzumi, Shunichi,Urano, Tsutomu,Suenobu, Tomoyoshi
, p. 213 - 214 (1996)
Photoinduced electron transfer from Fe2+ loaded in zeolite Y to the singlet excited state of 10-methylacridinium ion in the zeolite occurs to give the acridinyl radical which reduces 7,7,8,8-tetracyanoquinodimethane in acetonitrile solution to yield the radical anion; the back electron transfer from the radical anion to Fe3+ across the zeolite-solution interface is shown to be negligibly slow.
MECHANISM OF THE HYDRIDE TRANSFER REACTION OF LEUCO CRYSTAL VIOLET WITH CYANOMETHYLENE ACCEPTORS
Nishimura, Norio,Zaman, Khan M.,Yamamoto, Shunzo
, p. 218 - 220 (1994)
In the hydride transfer reaction of Leuco Crystal Violet to form the Crystal Violet cation, the role of cyanomethylene acceptors was found to be essentially different from that of p-benzoquinones, both previously believed to act as ?-acceptors in the same manner.
Ultrafast exciton decay in PbS quantum dots through simultaneous electron and hole recombination with a surface-localized ion pair
Edme, Kedy,Bettis Homan, Stephanie,Nepomnyashchii, Alexander B.,Weiss, Emily A.
, p. 46 - 53 (2016)
This paper describes the ultrafast decay of the band-edge exciton in PbS quantum dots (QDs) through simultaneous recombination of the excitonic hole and electron with the surface localized ion pair formed upon adsorption of tetracyanoquinodimethane (TCNQ). Each PbS QD (R = 1.8 nm) spontaneously reduces up to 17 TCNQ molecules upon adsorption of the TCNQ molecule to a sulfur on the QD surface. The photoluminescence of the PbS QDs is quenched in the presence of the reduced TCNQ species through ultrafast (≤15-ps) non-radiative decay of the exciton; the rate constant for the decay process increases approximately linearly with the number of adsorbed, reduced TCNQ molecules. Near-infrared and mid-infrared transient absorption show that this decay occurs through simultaneous transfer of the excitonic electron and hole, and is assigned to a four-carrier, concerted charge recombination mechanism based on the observations that (i) the PL of the QDs recovers when spontaneously reduced TCNQ1- desorbs from the QD surface upon addition of salt, and (ii) the PL of the QDs is preserved when another spontaneous oxidant, ferrocinium, which cannot participate in charge transfer in its reduced state, is substituted for TCNQ.
Microelectrochemical measurements of electron transfer rates at the interface between two immiscible electrolyte solutions: Potential dependence of the ferro/ferricyanide-7,7,8,8-tetracyanoquinodimethane (TCNQ)/TCNQ?- system
Unwin,Zhang
, p. 3820 - 3827 (2002)
The reduction of 7,7,8,8-tetracyanoquinodimethane (TCNQ) in 1,2-dichloromethane (DCE) and nitrobenzene (NB), by aqueous ferrocyanide, and the back reaction were studied by scanning electrochemical microscopy. The effect of galvanic potential at the interface between two immiscible electrolyte solutions (ITIES) on electron transfer (ET) rates, with different electrolyte concentrations in the organic phase was evaluated. The ET rate constants for the forward and back reaction depended strongly on the interfacial potential drop, with an apparent ET coefficient close to 0.5. TCNQ?- was confined to DCE, but transferred from NB to water under certain experimental conditions, which could complicate kinetic analysis. The ET kinetics for the water/DCE system were analyzed further using Marcus theory. Close to zero driving force, the rate constants for the forward and back reaction were similar and in good agreement with predictions from Marcus theory with a sharp liquid/liquid interface. At equilibrium (when the forward and back ET rate constants were equal), the sharp boundary model for the ITIES predicted a bimolecular rate constant close to that measured experimentally.
Electron Transfer Reaction between Δ2,2'-Bi-1,3-dithiole (TTF) and 7,7,8,8-Tetracyanoquinodimethane (TCNQ). Electron Donating Property of TTF
Yamagishi, Akihiko,Iida, Yoichi
, p. 1340 - 1343 (1980)
The reaction between Δ2.2'-bi-1,3-dithiole (TTF) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) in acetonitrile solution, TTF + TCNQ = TTF +. =TCNQ -., was analyzed spectrophotometrically.The thermodynamical data of chemical equilibrium were determined to be K=(2.8 +/- 0.1)*10-3 at 11 deg C, ΔH=-6.7 +/-1.3 kJ mol -1 and Σ=-72.8 +/- 17 JK-1mol-1.The reaction-rate study of the equilibrium in several solvents was also made by temperature-jump technique.The difference in the electron-donating properties between TTF and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) is discussed by comparing the results with those of the reaction between TMPD and TCNQ.
Electrically conducting TCNQ Derivatives of Copper Sulphur/Nitrogen Chelates; Structure of a Novel Semiconducting Complex 2 which contains N-bonded TCNQ (pdto=1,8-di-2-pyridyl-3,6-dithiaoctane; TCNQ=7,7,8,8-tetracyanoquinodimethane)
Humphrey, David G.,Fallon, Gary D.,Murray, Keith S.
, p. 1356 - 1358 (1988)
Reaction in water of Cu(pdto)(ClO4)2 with Li(TCNQ)/TCNQ mixtures yields solid crystalline materials of formulae Cu(pdto)(TCNQ)x (x=2, 2.5, or 3) which display high electrical conductivities ; reaction of Cu(pdto)(ClO4) with Li(TCNQ) yields Cu(pdto)(TCNQ), a poor conductor which has been shown by X-ray crystallography to have a novel dimeric structure involving ?-? interaction between TCNQ units and which possesses Cu-TCNQ bonding.
Positive dendritic effects on the electron-donating potencies of poly(propylene imine) dendrimers
Ong, Winston,McCarley, Robin L.
, p. 1287 - 1290 (2005)
(Chemical Equation Presented) Two series of poly(propylene imine), PPI, dendrimers terminated with a redox-active donor, 4-dimethylaminobenzyl (4-DMAB), including their respective nondendronized model compounds, are reported. In these two series, a positive dendritic effect was observed for the formation of charge-transfer (CT) complexes between the dendrimers and 7,7,8,8- tetracyanoquinodimethane (TCNQ). However, the nondendronized compounds did not form CT complexes with TCNQ, even though their redox potentials are similar to those of the 4-DMAB units attached to the dendrimers.
Effect of comproportionation on voltammograms for two-electron reactions with an irreversible second electron transfer
Lehmann, Mark W.
, p. 1947 - 1950 (1999)
Many organic and organometailic compounds are reduced or oxidized in two steps with the addition or removal of the second electron occurring with greater difficulty than the first In such EE reactions, a comproportionation reaction can occur in solution near the electrode by which the final product exchanges an electron with the reactant to form two molecules of the intermediate species. Normally, this comproportionation reaction has little or no effect in voltammetry. In this paper, a substantial effect of comproportionation is predicted for the case where the second electron-transfer reaction is irreversible. In steady-state voltammetry, the normally symmetric, sigmoid-shaped second wave is predicted to rise more sharply near its base than is observed in the absence of comproportionation and, in the limit of a very fast comproportionation reaction, an "onset potential" develops at which the current at the second wave increases abruptly from the limiting current of the first plateau. Experimental examples of these effects are presented for the reduction of tetracyanoquinodimethane in acetonitrile by steady-state microelectrode voltammetry, normal-pulse voltammetry, and cyclic voltammetry.
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.
Controlled nanoscale mechanical phenomena discovered with ultrafast electron microscopy
Flannigan, David J.,Lobastov, Vladimir A.,Zewail, Ahmed H.
, p. 9206 - 9210 (2008/12/22)
On again, off again: The reversible expansion and contraction of single crystals of [Cu(TCNQ)] induced by near-infrared laser pulses was studied with ultrafast electron microscopy (TCNQ = 7,7,8,8-tetracyanoquinodimethane). The crystal expands along the σ-
