2005 Fiscal Year Final Research Report Summary
ANALYSIS OF DYNAMIC STRUCTURE WITH CHEMICAL SHIFT SIMULATION METHOD
| Project/Area Number |
15350025
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Organic chemistry
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
FUKAZAWA Yoshimasa Hiroshima University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (50004502)
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| Co-Investigator(Kenkyū-buntansha) |
IWAMOTO Hajime Hiroshima University, Graduate School of Science, Reseach Associate, 大学院・理学研究科, 助手 (80304393)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Chemical Shift Simulation / Induced Magnetic Shielding / New Chiral Auxiliary / Absolute Configuration / Porphvrin Ring Current / 環電流効果 |
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| Research Abstract |
Determination of significantly populated conformers in extremely flexible molecules is a matter of long-standing interest. It is desirable to develop an efficient method for the conformational analysis of the flexible compounds. NMR chemical shifts reflect molecular structure. Hence, variation in the local environment affects chemical shieldings, and the change in chemical shifts of nuclei caused by adjacent substituents provides valuable information about the relative arrangement of the nuclei under study with respect to these nearby substituents. The chemical shift changes caused by the nearby substituents can thus be applicable for conformational analysis. From this point of view, we have developed an efficient method for conformational analysis of flexible organic compounds by using chemical shift simulation technique. The followings are the results of the project.
(1) Magnetic shielding effects of polar functional groups were successfully estimated and were applied for the conformational analysis of the flexible compounds, including cyclophanes, molecular tweezers, and their supramolecular complexes.
(2) A very useful model of porphyrin ring current effect was developed by using a classical line current approximation. It was found that the model can successfully elucidate the structures of several dicarboxylate complexes of Sn^<(IV)> porphyrins in solution.
(3) The newly developed method for the conformational analysis by using chemical shift simulation technique was found to be highly efficient for the structure elucidation of flexible organic compounds.
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