A study of the donor properties of the phenoxachalcogenines II: 7,7,8,8-tetracyanoquinodimethane as the acceptor

1980 ◽  
Vol 58 (11) ◽  
pp. 1133-1137 ◽  
Author(s):  
David P. Rainville ◽  
Ralph A. Zingaro ◽  
John P. Ferraris
Keyword(s):  
Free Energy ◽  
Charge Transfer ◽  
Room Temperature ◽  
Charge Transfer Complex ◽  
Equilibrium Constants ◽  
Entropy Change ◽  
Charge Transfer Complexes ◽  
Chalcogen Atom ◽  
Dc Conductivities ◽  
Type Interaction

The phenoxachalcogenines have been studied as donors towards 7,7,8,8-tetracyanoquinodimethane. For the 1:1 complexes studied, the equilibrium constants, K, vary over the range 4–6; the enthalpy, ΔH0, is about −2.0 kcal/mol; the free energy, ΔG0, is −1.4 to −1.0 kcal/mol, and the entropy change, ΔS0, is −7.3 to −3.5 eu. The entropy change is greatest in the case of the dibenzo-1,4-dioxane – 7,7,8,8-tetracyanoquinodimethane charge-transfer complex. This is attributed to the planarity of the dibenzo-1,4-dioxane molecule. The extinction coefficient, εc, for the series studied varies from 115 to 230, and no regularity in the trend has been noted.The lack of any significant changes (with change in the chalcogen atom) in the thermodynamic values for the phenoxachalcogenine – 7,7,8,8-tetracyanoquinodimethane charge-transfer complexes is interpreted in terms of a similar π to π type interaction involving a delocalized π orbital of the phenoxachalcogenine rather than a localized n orbital of the hetero atom.The room temperature four-probe dc conductivities of single crystals of PSe–TCNQ and PS–TCNQ were found to be 4 × 10−8 and 3 × 10−7 ohm−1 cm−1, respectively.

scholarly journals Investigation of Charge Transfer Complexes Formed between Mirtazapine and Someπ-Acceptors

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Hulya Demirhan ◽  
Mustafa Arslan ◽  
Mustafa Zengin ◽  
Mustafa Kucukislamoglu
Keyword(s):  
Charge Transfer ◽  
Dosage Form ◽  
Room Temperature ◽  
Equilibrium Constants ◽  
Formation Constants ◽  
Electron Acceptors ◽  
Spectral Studies ◽  
Charge Transfer Complexes ◽  
Ir And Nmr Spectroscopy ◽  
Ft Ir

Charge transfer complexes (CTC) of mirtazapine with tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), and tetracyanoquinodimethane (TCNQ) have been studied spectrophotometrically in dichloromethane at room temperature. The stoichiometries of the complexes were found to be 1 : 1 ratio by the Job Method between mirtazapine and the acceptors. The equilibrium constants and thermodynamic parameters of the complexes were determined by the Benesi-Hildebrand and Van't Hoff equations. Mirtazapine in pure and dosage 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 FT-IR and NMR spectroscopy.

CHARGE-TRANSFER COMPLEXES OF BIPHENYLENE

1966 ◽  
Vol 44 (1) ◽  
pp. 9-12 ◽  
Author(s):  
P. H. Emslie ◽  
R. Foster ◽  
R. Pickles
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complex ◽  
Equilibrium Constants ◽  
Charge Transfer Complexes ◽  
Kcal Mole ◽  
Dichloromethane Solution ◽  
Entropy Of Formation ◽  
Charge Transfer Transitions ◽  
Different Temperatures ◽  
Enthalpy And Entropy

An attempt has been made to redetermine the enthalpy and entropy of formation of the charge-transfer complex between tetracyanoethylene and biphenylene in dichloromethane solution from measurements of the equilibrium constant at different temperatures. The results obtained under conditions where biphenylene is in excess differ from those previously published in which tetracyanoethylene was in excess. It is argued that the optimum condition for determining equilibrium constants of a 1:1 complex is when the reactants are mixed in solution in this ratio. Determinations under this condition yield ΔH = −2.6 kcal mole−1 and ΔS = −4.1 e.u.The energies of the intermolecular charge-transfer transitions of biphenylene with several different acceptors suggest that the ionization potential of biphenylene is ~7.4 eV.

Charge-Transfer Complexes of Brominated Polycyclic Aromatic Hydrocarbons

1962 ◽  
Vol 15 (2) ◽  
pp. 278 ◽  
Author(s):  
TM Spotswood
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Charge Transfer ◽  
Aromatic Hydrocarbons ◽  
Charge Transfer Complex ◽  
Equilibrium Constants ◽  
Molecular Complexes ◽  
Charge Transfer Complexes ◽  
Extinction Coefficients ◽  
Polycyclic Aromatic ◽  
Molar Extinction Coefficients

Charge-transfer complex formation between the donors 1-bromonaphthalene. 9-bromophenanthrene, 9-bromoanthracene, 3-bromopyrene, and 7-bromobenz[a]-anthracene and the acceptors iodine, tetrachlorophthalic anhydride, 1,3,5-trinitrobenzene, and 2,4,7-trinitrofluorenone has been investigated. The positions of the charge-transfer absorption maxima, apparent molar extinction coefficients, and equilibrium constants have been determined in carbon tetrachloride solution and the results compared with those for the corresponding unsubstituted polycyclic aromatic hydrocarbons. The positions of the absorption maxima of the charge-transfer bands of the brominated hydrocarbons were anomalous but the apparent molar extinction coefficients and equilibrium constants were similar to those obtained for the parent hydrocarbons. The strength of charge-transfer bonding in molecular complexes of brominated polycyclic aromatic hydrocarbons is shown to be of the same order as that in molecular complexes of the unsubstituted hydrocarbons.

Chemical shifts of charge-transfer complexes and Buckingham equation

1990 ◽  
Vol 55 (9) ◽  
pp. 2131-2137
Author(s):  
Mahboob Mohammad ◽  
Ather Yaseen Khan ◽  
Tariq Mahmood ◽  
Ismat Fatima ◽  
Riffat Shaheen ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Nmr Spectra ◽  
Charge Transfer Complex ◽  
Chemical Shifts ◽  
Charge Transfer Complexes ◽  
Aprotic Solvents ◽  
Reaction Field ◽  
H Nmr ◽  
Spherical Cavities ◽  
Dipolar Aprotic Solvents

The 1H NMR spectra of the charge-transfer complex of 1-ethyl-4-methoxycarbonylpyridinium iodide have been recorded in various dipolar aprotic solvents. An attempt is made to interpret the chemical shifts in terms of Buckingham's reaction field equation for spherical cavities. A linear dependence has been found between the δ(2,6) values and the square of dielectric function for a spherical cavity, which confirms the validity of the Buckingham equation for this class of compounds.

Gelification Effects on the Structure and Birefringence of Charge Transfer Complex Terthiophene Bisililated – TCNQ Hybrid Materials

2006 ◽  
Vol 517 ◽  
pp. 257-261
Author(s):  
N. Kancono ◽  
H.B. Senin
Keyword(s):  
Charge Transfer ◽  
Detection Limit ◽  
Hybrid Materials ◽  
Vibrational Spectra ◽  
Lamellar Structure ◽  
Radical Anion ◽  
Charge Transfer Complex ◽  
Visible Spectrum ◽  
Charge Transfer Complexes

Charge transfer complexes (CTC) can be readily introduced into materials by cohydrolysis-copolymerisation of bis-silylated ter-thiophenes as precursors with TMOS and TEOS in the presence of TCNQ. CTC formation is shown in the visible spectrum of the xerogel by the band at 850 nm characteristic of the TCNQ·- radical anion. Vibrational spectra have shown that strong vibration of C≡N bond at 2184, 2120 and 1595 cm-1 as peaks characteristics of CTC. The CTC bands are weak and the complex is easily destroyed by washing with acetone, which removes the TCNQ. The gelification effect of the charge transfer complexes on the hybrid materials of 2,5’’- bis(trime thoxysilyl)terthiophene/TCNQ/ TMOS showed that the peak with distance of more than 11.68 Å, formed by precursors and matrices, as a lamellar structure. The birefringence of xerogel BTS3T in presence of alkoxysilane showed that the value is near the detection limit of 0.1 – 0.4 x 10-3, which is weaker than BTS3T / THF with the birefringence value of 4.5 x 10-3.

scholarly journals Fermi level pinned molecular donor/acceptor junctions: reduction of induced carrier density by interfacial charge transfer complexes

2020 ◽  
Vol 8 (43) ◽  
pp. 15199-15207
Author(s):  
Paul Beyer ◽  
Eduard Meister ◽  
Timo Florian ◽  
Alexander Generalov ◽  
Wolfgang Brütting ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Fermi Level ◽  
Carrier Density ◽  
Charge Transfer Complex ◽  
Charge Transfer Complexes ◽  
Interfacial Charge Transfer ◽  
Fermi Level Pinning ◽  
Donor Acceptor ◽  
Interfacial Charge

Charge transfer complex (CPX) formation at a donor–acceptor interface reduces the amount of Fermi-level pinning induced interfacial charge transfer.

Determination of Equilibrium Constants for Weakly Bound Charge-transfer Complexes

1999 ◽  
Vol 69 (4) ◽  
pp. 443-447 ◽  
Author(s):  
Ramona Zaini ◽  
Andrew C. Orcutt ◽  
Bradley R. Arnold
Keyword(s):  
Charge Transfer ◽  
Equilibrium Constants ◽  
Charge Transfer Complexes ◽  
Weakly Bound

Room-temperature fluorescence of a charge-transfer complex of reserpine in aqueous and aqueous–ethanol media

2011 ◽  
Vol 109 (14) ◽  
pp. 1805-1811 ◽  
Author(s):  
Bankim Chandra Ghosh ◽  
Asok K. Mukherjee
Keyword(s):  
Charge Transfer ◽  
Room Temperature ◽  
Aqueous Ethanol ◽  
Charge Transfer Complex ◽  
A Charge

Electrical Properties of CuTCNQ Based Organic Memories Targeting Integration in the CMOS Back End-of-Line

2007 ◽  
Vol 997 ◽  
Author(s):  
Robert Mueller ◽  
Joris Billen ◽  
Rik Naulaerts ◽  
Olivier Rouault ◽  
Ludovic Goux ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Thermogravimetric Analysis ◽  
Electrical Properties ◽  
Room Temperature ◽  
Charge Transfer Complex ◽  
Temperature Dependent ◽  
Electrical Switching ◽  
Nonvolatile Memories ◽  
Threshold Voltages ◽  
Organic Memories

AbstractCuTCNQ (TCNQ=7,7,8,8-tetracyanoquinodimethane) is a resistive switching charge-transfer complex which can be used for organic nonvolatile memories. In this contribution we report on a thorough investigation of the electrical switching of CuTCNQ memories. Our memories currently achieve an endurance of up to 10000 write/erase cycles with a clear distinction between ON and OFF reading currents. ON and OFF threshold voltages follow a Gaussian distribution. Temperature dependent measurements of CuTCNQ based organic memories show a semiconductor like behavior for the ON state. The retention time of the ON state exceeded 60 hours at room temperature. Electrical switching of CuTCNQ memories in air was virtually not affected by temperatures up to 80°C, but becomes erratic at 120°C. The CuTCNQ material itself already starts to decompose around 200°C in presence of oxygen as shown by thermogravimetric analysis.

Chemical and spectroscopic studies in metal β-diketonates. IX. A novel intermolecular charge-transfer system involving metal acetylacetonate (donor) and iodine (acceptor)

1970 ◽  
Vol 23 (2) ◽  
pp. 269 ◽  
Author(s):  
PR Singh ◽  
R Sahai
Keyword(s):  
Charge Transfer ◽  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Spectroscopic Studies ◽  
Charge Transfer Complexes ◽  
Transfer System ◽  
Metal Acetylacetonates ◽  
Iodine Complex ◽  
Straight Line ◽  
Metal Acetylacetonate

A spectrophotometric study of 1 : 1 charge-transfer complexes derived from five metal acetylacetonates (donor) and iodine (acceptor) has been carried out. Iomzation potential of each metal acetylacetonate and the equilibrium constants for the formation of the chelate-iodine complex have been evaluated. The plot of ionization potential of donors against hvCt values gave a straight line.

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