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• 603-48-5 tris[4-(dimethylamino)phenyl]methane 
• 1518-16-7 7,7',8,8'-tetracyanoquinodimethane 
• 370-14-9 pholedrine 
• 1518-16-7 7,7,8,8-tetracyanoquinodimethane radical anion 
• 1518-16-7 7,7,8,8-tetracyanoquinodimethane radical anion 

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• 1518-16-7 7,7,8,8-tetracyanoquinodimethane radical anion 

Relevant academic research and scientific papers

Electrochemical studies of heterogeneous reduction of tetracyanoquinodimethane in poly(ethylene oxide) electrolytes using ac impedance and cyclic voltammetry at an ultramicroelectrode

Electrochemical studies of the TCNQ0/TCNQ- couple have been carried out using ac impedance spectroscopy and cyclic voltammetry at platinum ultramicroelectrodes (UME). Liquid poly(ethylene oxide) (PEO) CH3-O-(CH2-CH2-O4)-CH3 has been used as the solvent with different concentrations of the TCNQ0/TCNQ- couple and LiClO4 as the supporting electrolyte. On the basis of the ac impedance results at the UME it has been found that the double layer capacitance and standard heterogeneous rate constant are independent of the presence of electroactive species and supporting electrolyte concentrations, indicating that adsorption of electroactive species onto the electrode is not significant. The standard heterogeneous rate constant ks was found to be 0.109 ± 0.005 cm s-1. A similar value of k(s) = 0.094 cm s-1 was obtained for the second reduction step TCNQ-/TCNQ2-. Diffusion coefficients of both TCNQ and TCNQ- are equal, D = 1.0 x 10-6 cm2 s-1 for a 0.5 M LiClO4 solution. Higher diffusion coefficients are obtained in less concentrated supporting electrolyte. Comparison is made between these results and those reported previously for PEO-400 HO-(CH3CH2O)8-OH. The different end groups significantly influence the viscosity and hence k(s).

Ultrafast exciton decay in PbS quantum dots through simultaneous electron and hole recombination with a surface-localized ion pair

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.

Effect of comproportionation on voltammograms for two-electron reactions with an irreversible second electron transfer

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.

In Situ Electrochemical EPR Studies of Charge Transfer across the Liquid/Liquid Interface

The in situ measurement of EPR spectra of radical ions generated at the polarized liquid/liquid interface is described in relation to the 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3,5,6-tetrachloro-p-benzoquinone (TCBQ), and 2,3,5,6-tetrafluoro-p-benzoquinone (TFBQ) radical anions and the tetrathiafulvalene (TTF) radical cation. TCNQ and TTF were chosen as model compounds with which to quantify the performance of a novel liquid/ liquid electrochemical EPR cell. The anion radical of TCNQ and the cation radical of TTF in 1,2-dichloroethane (DCE) were produced at the water interface by electron transfer from/to the aqueous-phase ferricyanide/ferrocyanide redox couple by applying a potential difference between the two phases with a four-electrode potentiostat. The EPR signal intensity (at constant magnetic field) of the resultant organic radicals was monitored during potential step experiments which indicated that the EPR data could be modeled in terms of diffusional transport. TCBQ and TFBQ were chosen as compounds to model the electron transfer behavior of biologically important quinones at the oil/water interface. The EPR and voltammetric data obtained from TCBQ/TCBQ-· and TFBQ/ TFBQ-· indicated unambiguously that the two semiquinones are stable at the DCE/water interface and do not undergo immediate protonation.

Spectroscopic studies of molecular interaction of 2-thiouracil and dithiouracil donors with 7,7,8,8-tetracyanoquinodimethane as an electron acceptor

The electronic absorption and electron spin resonance studies on the interaction of thiouracil and dithiouracil as donors with 7,7,8,8-tetracyanoquinodimethane (TCNQ) as an acceptor reveal that the absorption bands in these systems are not due to the charge transfer complex but are due to the formation of products (free radical in nature). The equilibrium constants, K, for the D-A systems as determined from the Benesi Hildebrand model follow the direct trend of pKH of the donors and K(dithiouracil) > · K(thiouracil).

MECHANISM OF THE HYDRIDE TRANSFER REACTION OF LEUCO CRYSTAL VIOLET WITH CYANOMETHYLENE ACCEPTORS

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.