Showing papers by "Takashi Kubo published in 1998"
TL;DR: In this paper, a four-stage amphoteric redox hydrocarbon (5) containing two phenalenyl units was prepared and four reversible redox waves with a small numerical sum of first oxidation (E1ox) and reduction potentials were successfully generated from the neutral 5 and were characterized by NMR, ESR, and UV−vis−near-IR spectroscopies.
Abstract: A four-stage amphoteric redox hydrocarbon (5) containing two phenalenyl units was prepared. X-ray crystallography of 5 reveals a delocalized D2h structure, which is consistent with the presence of only five signals in the 1H NMR spectrum of 5 at −60 °C. The cyclic voltammogram of 5 exhibits four reversible redox waves with a small numerical sum (E1sum) of first oxidation (E1ox) and reduction (E1red) potentials. Four redox states of 5 were successfully generated from the neutral 5 and were characterized by NMR, ESR, and UV−vis−near-IR spectroscopies and theoretical calculations. These spectral data reveal that phenalenyl units play an important role in the high amphotericity of 5 and the stability of the redox states generated.
108 citations
TL;DR: In this article, a spin-parity assignment has been made for several states in the nuclear reaction at 70 MeV, based on the observed transferred angular momentum dependence of the angular distributions, and the level shifts in these states were analyzed in terms of the isobaric multiplet mass equation.
Abstract: The nuclear structure of ${}^{17}\mathrm{Ne}$ has been studied by the ${}^{20}{\mathrm{N}\mathrm{e}(}^{3}{\mathrm{H}\mathrm{e},}^{6}{\mathrm{H}\mathrm{e})}^{17}\mathrm{Ne}$ reaction at 70 MeV. Thirteen levels were identified in ${}^{17}\mathrm{Ne},$ and angular distributions have been measured for the first time for this reaction. Based on the observed transferred angular momentum dependence of the angular distributions, a spin-parity assignment has been made for several states in ${}^{17}\mathrm{Ne}.$ With the inclusion of the data on ${}^{17}\mathrm{Ne},$ $T=\frac{3}{2}$ quartet analog states have been completed for six levels in the $A=17$ isobar system. The level shifts in these $A=17$ nuclei are analyzed in terms of the isobaric multiplet mass equation (IMME). The results of such an analysis show a slight linear dependence of the $b$ and $c$ coefficients of the equation on the excitation energy. The coefficients for the positive parity states seem to follow a different systematics than the negative parity states, suggesting that these parity-dependent level shifts are reflecting the structure change. These coefficients of the IMME are discussed.
12 citations