| Project/Area Number |
12640490
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | The University of Electro-Communications |
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Principal Investigator |
IWASAKI Fujiko The University of Electro-Communications, faculty of Electro-communications Dept.of Applied Physics and Chemistry, Professor, 電気通信学部, 教授 (10017329)
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| Co-Investigator(Kenkyū-buntansha) |
HASHIZUME Daisuke RIKEN, Institute of Physical and Chemical research, Molecular Characterization Division, Researcher, 物質基盤研究部, 研究員 (00293126)
YASUI Masanori The University of Electro-Communications, Faculty of Electro-Communications, Dept.of Applied Physics and Chemistry, Associate professor, 電気通信学部, 助教授 (00201822)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | X-ray crystal structure analysis / temperature-resolved X-ray structure analysis / phase transition / organic crystals / powder diffraction method / acylurea / acridin-N-oxyl derivatives / pentacoordinated boron compound / 銅錯体 / 超原子価B化合物 / フェナントリジンニトロキシド / アルキル鎖のコンホメーション |
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| Research Abstract |
Very few studies have been done on the detailed structural changes during transitions, because of the crystal damage and difficulties of intensity measurements for single crystal structure analyses at various temperatures. Recently, temperature-resolved structure analyses became possible through the development of diffractometers with two-dimensional detectors. Crystals of acridin-N-oxyl derivatives with a long alkyl chain (CnH2n+1, n=12, 13) showed that the first order. In the case of the n=13, the single crystalline states were kept during the transition. Structure analyses were carried out every 2 K during the transition from 264 to 252 K and at 295, 280, 273, 244 and 100 K. Crystals of a acylurea derivative, iso-C_5H_<11>-CO-NH-CO-NH-C_2H_5 showed a phase transition at 367K (mp=378 K) and also kept single-crystalline-state during the transition. Structure analyses were performed at 98, 298, 328 K and in the range of 348 ~ 374 K every 2 K. For Crystals ClCH_2-CO-NH-CO-NH-C_5H_<11>,
… More
powder diffraction method was performed because of crystalline damage. In these crystals, intermediate stages and mechanism of phase transitions caused by the conformational changes of alkyl groups induced by the thermal expansion was revealed. A pentacoordinated boron compound bearing 1, 8-dimethoxyanthracene and dithiocatecholato ligands showed the second-order phase transition, Pnma at high temperature phase and P2_12_12_1 at low temperature phase. Temperature-dependent structure analyses were performed every 2 K during phase transition. Following the thermal expansion, the catecholate moieties begin to librate even from 120 K and become disordered at 203 K. Intermolecular energies were calculated using simple force field potentials for the neighboring molecular pairs at each temperature. The energy barrier between ordered and disordered structures at the transition point was estimated about 1 kJ/mol
X-ray crystal structure analysis 2 temperature-resolved X-ray structure analysis (3) phase transition 4) organic crystals (5) powder diffraction method (6 acylurea 7 acridin-N-oxyl derivatives (8) pentacoordinated boron compound Less
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