57Feラベル付オクタメチルフェロセニウムテトラフルオロボラート. 構成性同位体,超微細相互作用,およびモースバウアー光譜によるスピン・ラットのリラクゼーションのX線結晶構造
Herwig Schottenberger1, Klaus Wurst, Ulrich J Griesser
1Faculty of Chemistry and Pharmacy, University of Innsbruck, 6020 Innsbruck, Austria. herwig.schottenberger@uibk.ac.at
Journal of the American Chemical Society
|May 5, 2005
まとめ
オクタメチルフェロセニウムテトラフルオロボラート (OMFc (((+)) BF (((4) ((-)) は,小さな格子エネルギー差による構造的多形性を表しています. ニュートラルなOMFcとは異なり,OMFc ((+) BF ((4))) は金属原子の動きが突然増加することはなく,明確なダイナミクスを示しています.
科学分野:
- 有機金属化学 有機金属化学
- 固体化学 固体化学
- クリスタルグラフィーです.
背景:
- オクタメチルフェロセニウムテトラフルオロボラート (OMFc (((+)) BF (((4) ((-)) は,材料科学における潜在的な応用を持つ有機金属化合物である.
- ポリモルフィズムとダイナミクスを含む固体状態の性質を理解することは,技術的な利用に不可欠です.
研究 の 目的:
- OMFc (((+)) BF (((4) ((-)) の形状的多形性を調査する.
- OMFc ((+)) BF ((4) ((-)) の鉄原子の温度依存のダイナミクスを研究する.
- OMFc (((+)) BF (((4) ((-)) でのスピンリラクゼーションプロセスと固体-固体移行を特徴づける.
主な方法:
- 単一結晶のX線構造の決定.
- (57) Feで標識されたOMFc (((+)) BF (((4) ((-)) の温度に依存するモースバウアー光譜.
主要な成果:
- OMFc (((+) BF (((4) ((-) の2つの異なる結晶形が特定され,リガンドの回転角度 (180°と108°) で異なるが,これは小さな格子エネルギー差 (3.2 kJ mol ((-1)) に起因する.
- モースバウアー光譜は,中性OMFc.とは異なり,370Kまでの金属原子運動の異常な増加を明らかにしなかった.
- リラクゼーションスペクトルは,オルバッハプロセスによって最もよく説明されるスピンリラクゼーションを示しており,モースバウアー格子温度は89Kです.
- プラスチックの結晶メソフェーズへの可逆的な固体-固体移行は400 Kで発生しました.
結論:
- OMFc ((+) BF ((4))) は,微妙な格子エネルギー変動によって引き起こされる構造的多形性を表している.
- OMFc (((+) BF (((4))) の鉄中心のダイナミクスは,異なるスピンリラクゼーションメカニズムを持つ中立の同位体とは著しく異なります.
- 化合物は,高温で,プラスチック結晶メソフェーズへの可逆的相変化を経験します.
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