Elastic and Inelastic Electron Tunneling Spectroscopy of a New Rectifying Monolayer
摘要:
Rectification of electrical current was observed in a Langmuir-Schaefer monolayer of fullerene-bis[ethylthio-tetrakis(3,4-dibutyl-2-thiophene-5-ethenyl)-5-bromo-3,4-dibutyl-2-thiophene] malonate, Au electrodes at room temperature (there are two regimes of asymmetry, at lower bias, i.e., between 0 and +/- 2 V, and at higher bias), and also between Pb and Al electrodes at 4.2 K. The latter experiment was coupled with second harmonic detection of the second derivative of the current with respect to voltage (d(2)I/dV(2)). The d(2)I/dV(2) spectrum shows intramolecular vibrations, and also two antisymmetric broad bands, centered at +/- 0.65 V, due to resonant electron tunneling between the Fermi level(s) of the electrodes and the lowest unoccupied molecular orbital of the molecule.
Thienylenevinyleneoligomers (nTVs) containing up to 10 thiophene rings and bearing solubilizing hexyl groups at the α-position of the end thiophene rings or octyl or dibutyl chains at the 3-position or the 3- and 4-positions of the thiophene rings have been synthesized by a combination of formylation reaction, Wittig−Horner olefination, and McMurry dimerization. Owing to the good solubility imparted
Elastic and Inelastic Electron Tunneling Spectroscopy of a New Rectifying Monolayer
作者:Andrei Honciuc、Robert M. Metzger、Aijun Gong、Charles W. Spangler
DOI:10.1021/ja068729g
日期:2007.7.1
Rectification of electrical current was observed in a Langmuir-Schaefer monolayer of fullerene-bis[ethylthio-tetrakis(3,4-dibutyl-2-thiophene-5-ethenyl)-5-bromo-3,4-dibutyl-2-thiophene] malonate, Au electrodes at room temperature (there are two regimes of asymmetry, at lower bias, i.e., between 0 and +/- 2 V, and at higher bias), and also between Pb and Al electrodes at 4.2 K. The latter experiment was coupled with second harmonic detection of the second derivative of the current with respect to voltage (d(2)I/dV(2)). The d(2)I/dV(2) spectrum shows intramolecular vibrations, and also two antisymmetric broad bands, centered at +/- 0.65 V, due to resonant electron tunneling between the Fermi level(s) of the electrodes and the lowest unoccupied molecular orbital of the molecule.
Protonation behavior of thiaporphyrin and thiabenzoporphyrin
作者:Kazunari Tagawa、Shigeki Mori、Tetsuo Okujima、Masayoshi Takase、Hidemitsu Uno
DOI:10.1016/j.tet.2016.12.067
日期:2017.2
The protonation behavior of bicyclo[2.2.2]octadiene (BCOD)-fused thiaporphyrin and thiabenzoporphyrin was examined by titration with trifluoroacetic acid. Neutral, monorotonated, and diprotonated species of thiaporphyrins were easily detected by UV–vis spectral measurement. The first (K1) and second (K2) equilibrium constants were found to be K1 = 520 and K2 ≈ 7.1 for BCOD-fused thiaporphyrin and K1 = 1