フェナレニル基の分子導体におけるヒステリックスピンと電荷移位
Sushanta K Pal1, Pradip Bag, Arindam Sarkar
1Department of Chemistry, University of California, Riverside, California 92521-0403, USA.
Journal of the American Chemical Society
|November 18, 2010
まとめ
この研究は,相変化を示すブチル置換フェナレニル基の2つの異なる電子状態を明らかにしています. ダイマー内の平面間 π-π 距離は,そのヒステレティックな性質の鍵です.
科学分野:
- 固体化学 固体化学
- マテリアルサイエンス 材料科学
- オーガニック・エレクトロニクス
背景:
- フェナレニル基の中性ラジカルは,それらの電子特性のために興味があります.
- 有機物質のヒステリック相変遷は,二次安定状態につながる可能性があります.
- 構造と性質の関係を理解することは,機能的な材料を設計する上で極めて重要です.
研究 の 目的:
- ブチル置換フェナレニル基の固体電子構造と性質を調査する (3).
- 電子密度分布を分析し,ヒステレスループ内の異なる電子状態を特定する.
- 観察されたヒステリック・フェーズ・トランジションに起因する構造的要因を解明する.
主な方法:
- 様々な温度で結晶構造を分析するために,固体X線 difraktion.
- 電子状態を調査するための赤外線 (IR) 伝達スペクトロスコピー.
- 電子密度分布の定量分析 電子密度分布の定量分析
- 関連性のあるエチル置換ラジカルとの比較研究 (1).
主要な成果:
- ラジカル3のヒステレスループ内で2つの異なる電子状態を特定した.
- これらの電子状態のビスタビリティを,IR伝導度によって観測した.
- ダイマー内の平面間 π-π 距離の変化が物理的性質に決定的であることを決定した.
- C-H···π相互作用とスピンの再分布がヒステリシスを引き起こさないことを発見した.
結論:
- ラジカル3におけるヒステリック相移行は,主に平面間 π-π 距離の変化によって制御されます.
- 冷却中の高温状態は熱力学的に安定しています.
- 加熱中の低温状態は,大振幅のリング運動と格子再編成により,大きなエネルギーバリア (>100 kJ/mol) によって運動的に閉じ込められます.
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