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A quantum chemical study of interchain hopping model of negatively charged solitons in polyacetylene
Akitomo Tachibana Shigeru Ishikawa Yoshihiro Asai Hideki Katagiri Tokio Yamabe 《International journal of quantum chemistry》1992,41(3):461-474
Phonon-assisted interchain hopping of negatively charged solitons in polyacetylene has been studied using a local chemical reaction model CH + CH4 → CH4 + CH. Quantum chemical characteristics of the electron transfer process have been analyzed in terms of the dynamic electron density and the mutual polarization moment. The CH stretching vibrational motion of CH4, which is a local model of the sp3 defect, has been found to play a significant role for the electron transfer. The excitation of the corresponding vibrational mode of the sp3 defect would promote the interchain hopping of the charged soliton. The electron transfer process has also been studied in terms of the “regional” density functional theory. It has been shown that the driving force of the electron transfer is represented by the regional chemical potentials. 相似文献
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[structure: see text] A highly convergent synthetic route to the FGHIJKLM ring fragment of ciguatoxins has been developed, which relied on extensive use of the B-alkyl Suzuki-Miyaura coupling reaction. 相似文献
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Akimoto Tachibana Masahiko Koizumi Iwao Okazaki Hiroyuki Teramae Tokio Yamabe 《Theoretical chemistry accounts》1987,71(1):7-19
The non- and fluorine-substituted singlet carbonyl ylides are studied by using ab initio MCSCF calculations. The thermodynamic stability of the carbonyl ylides and the intramolecular stability to isomerization or fragmentation reaction coordinates is demonstrated in terms of the topological structure of the ab initio potential energy surfaces. The allylic resonance is found to be dynamically unstable, considering out-of-plane vibrational mode. The instability is studied by the symmetries of the low-lying excitations out of the MCSCF wave function. 相似文献
5.
Anna Miyazaki Yoshifumi Tachibana Eibai Lee Gyongyi Bokonyi Yuko Tsuda Yoshio Okada 《Tetrahedron letters》2004,45(33):6323-6327
It was reported that the somatostatin analog TT-232, d-Phe-c(Cys-Tyr-d-Trp-Lys-Cys)-Thr-NH2, exhibited a highly potent antitumor activity in vitro and in vivo. Using pyrazinone analogs and aliphatic amino acids instead of the disulfide bond, we prepared novel type somatostatin analogs including the sequence essential for antitumor activities, Tyr-d-Trp-Lys. These analogs exhibited antiproliferative effect on A431 tumor cells. 相似文献
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F Oka H Sagawa K Yabe A Okuyama M Tachibana T Noge K Torizumi S Okamoto M Yasui T Tuda 《Radioisotopes》1988,37(10):572-575
The patients receiving maintenance hemodialysis were divided into two groups in the absence and the presence of bone pain and investigated the markers of bone pain in these patients. These results suggested that the duration of receiving hemodialysis, serum concentrations of alkaline phosphatase, osteocalcin and parathyroid hormone became to be the markers of bone pain. 相似文献
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Yasuhiko Kawamura Kohji Akitomo Masaaki Oe Tokunaru Horie Masao Tsukayama 《Tetrahedron letters》1997,38(52):3610-8992
Upon irradiation (>340 nm) of a benzene solution of diazofluorene with di-p-tolyl- or di-p-anisyl disulfide, the corresponding 9,9′-bis(arylmercapto)bifluorenyl was afforded in moderate to good yield accompanied by formation of 9,9′-bis(arylmercapto)fluorene. The major reaction pathway is considered to be a disulfur ylide formation followed by two times of successive Stevens rearrangement or by concerted electron redistribution via [2,3]sigmatropic rearrangement. 相似文献
9.
The spin torque and zeta force, which govern spin dynamics, are studied by using monoatoms in their steady states. We find nonzero local spin torque in transition metal atoms, which is in balance with the counter torque, the zeta force. We show that d-orbital electrons have a crucial effect on these torques. Nonzero local chirality density in transition metal atoms is also found, though the electron mass has the effect to wash out nonzero chirality density. Distribution patterns of the chirality density are the same for Sc–Ni atoms, though the electron density distributions are different. 相似文献
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