トランス-2-ヒドロキシサイクロヘプタンカルボキシル酸の二極誘導ポリモルフで,実質的に同じ単細胞である
Alajos Kálmán1, László Fábián, Gyula Argay
1Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, Budapest 114, H-1525, Hungary. akalman@chemres.hu
Journal of the American Chemical Society
|January 8, 2003
まとめ
トランス-2-ヒドロキシサイクロヘプタンカルボキシル酸のポリモルフは,微妙な構造的な違いを示し,ユニークな結晶の積み重ねと二極の配置につながります. 純粋な形Iの結晶は,形IIとの相互浸透により分離できない.
科学分野:
- クリスタルグラフィーです.
- 固体化学 固体化学
背景:
- 有機分子におけるポリモルフィズムは,材料科学における課題を提示する.
- 結晶包装の理解は,材料の性質を予測するために不可欠です.
研究 の 目的:
- トランス-2-ヒドロキシサイクロヘプタンカルボキシル酸のポリモルフの構造的な違いを調査する.
- 結晶構造と二極の行動の関係を解明する.
主な方法:
- 結晶構造を決定するX線結晶学.
- スペースグループと格子パラメータの分析.
- 水素結合ネットワークと分子配列の調査.
主要な成果:
- 両ポリモルフの同一の格子パラメータ,イソモルフィズムを模倣する.
- 異なるスペースグループ (フォームIIのPn21,フォームIのPn21a) が結晶のパッキングを決定する.
- 形式IIは,反並列層の積み重ねを示し,ユニット細胞二極体を取り消す.
- 形式Iは平行層の積み重ねを示し,反平行ドメインが二極をキャンセルする.
- ドメインの境界で観察されたフォームI内のフォームIIの相互成長.
結論:
- トランス-2-ヒドロキシサイクロヘプタンカルボキシル酸の純粋な形Iは,形IIとの共結晶化により分離できない.
- 形式I内の形式IIの比率は,結晶によって異なるが,マクロスコピック特性に影響を与える.
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