ベータ・サイクロデクストリンのペラシル化が分子構造とインクルージョン複合体の形成に及ぼす影響:X線研究
M Añibarro1, K Gessler, I Usón
1Institut für Kristallographie, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany.
Journal of the American Chemical Society
|November 29, 2001
まとめ
ペラシル化β-サイクロデクストリン (CD) は,アシル鎖のステリック阻害により,歪んだ非平面構造を示します. この分子内腔閉塞は,溶液中のインクルージョン複合体の形成を防ぐ.
科学分野:
- 超分子化学 超分子化学
- 炭水化物化学 炭水化物の化学
- クリスタログラフィーです.
背景:
- ペラサイレートベータサイクロデクストリン (Peracylated beta-cyclodextrins,CDs) は,分子封じ込みに潜在的応用がある修正されたサイクロデクストリンです.
- 構造的ダイナミクスとホスト-ゲスト特性を理解することは,新しい機能的材料の設計に不可欠です.
研究 の 目的:
- 3つのペラサイレートされたβ-サイクロデクストリン:ヘプタキス (heptakis) 2,3,6-トリ-O-アセチル) -β-CD (TA),ヘプタキス (heptakis) 2,3,6-トリ-O-プロパノイル) -β-CD (TP),およびヘプタキス (heptakis) 2,3,6-トリ-O-ブタノイル) -β-CD (TB) の分子構造を解明する.
- これらのペラシル化CDの溶液相インクルージョン行動を,様々なゲスト分子と研究するために.
主な方法:
- 単結晶X線構造解析を用いて,TA,TP,TBの正確な3次元構造を決定した.
- 円形の二重化 (CD) スペクトロスコーピーは,溶液中のインクルージョン複合体の形成を研究するために使用されました.
主要な成果:
- ペラサイレーションにより,分子内水素結合が破壊され,マクロサイクルの円的歪みと非平面のボート状構造が生じます.
- グルコース単位は,アシル鎖からのステリックストレスを軽減するために,異なる形状の ((4) C ((1) 椅子または (O) S ((2) スキーボート) を採用します.
- CD腔にアシル鎖の分子内自己挿入が観察され,その穴を効果的に遮断した.
- 溶液に含まれるインクルージョン複合体は形成されず,これはアシル鎖が誘発した空洞の閉塞に起因する.
結論:
- この研究は,ネイティブCDと比較して,ペラサイレートされたβ-サイクロデクストリンに重大な構造的変化があることを示しています.
- 分子内アシル鎖の含有は,溶液中のこれらの改変サイクロデクストリンの宿主-ゲストの能力を制限する重要な要因です.
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