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トライゴナルピラミダ型鉄の家族における緩やかな磁気リラクゼーション (((II) ピロリド複合体
W Hill Harman1, T David Harris, Danna E Freedman
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|December 15, 2010
まとめ
調節可能なリガンド場を持つ高スピン鉄 (II) 複合体を合成し,緩やかな磁気緩和を観察しました. 複合体1は,単核移行金属複合体としては,これまでで最も高いスピン逆転バリアを示しており,磁気行動に関する洞察を提供します.
科学分野:
- 協調化化学について
- マグネト化学 マグネト化学
- マテリアルサイエンス 材料科学
背景:
- 三角ピラミッド型の鉄 (((II) 複合体は,磁気特性により興味を惹きます.
- 以前の研究では,メシチル誘導体 (複合体2) のゆっくりとした磁気放松が確認されました.
研究 の 目的:
- 異なるリガンドを持つ鉄 (II) 複合体の同類の連続を合成し,特徴づけること.
- 磁場強度が磁気行動,特に緩やかな磁気放松に及ぼす影響を調査する.
- 静的および動的磁性特性を,高度なスペクトロスコピーおよび磁性技術を使用して探査する.
主な方法:
- トリス・ピロリル-α-メチル) アミンのリガンドを持つ鉄 (II) 複合体の合成.
- 構造的決定のためのX線結晶学.
- 電子構造と磁性特性を調べるために,モッズバウアー光譜と高場EPR光譜を用いる.
- マグネチゼーションとAC磁気感受性の測定で,磁気アニソトロピーとリラクゼーションダイナミクスを決定する.
主要な成果:
- トライゴナルピラミッド型の鉄 (II) 複合体[M (solv) (n) ][tpa (R)) ]の一連の合成と特徴が示されました.
- 大量の単軸ゼロフィールド分割パラメータ (D) が観察され,リガンドフィールド強度によってスケーリングされた.
- 複合体1は,単核移行金属複合体の最高スピン逆転バリア (Ueff = 65 cm−1) を実証し,3つの異なるリラックスプロセスを特定しました.
- モッズバウアー光譜検査により,複合体1と複合体4の緩やかな磁気放緩が確認されました.
結論:
- リガンドフィールドの強さは,高スピン鉄 (II) 複合体の磁性アニソトロピーとリラクゼーションダイナミクスに大きな影響を与える.
- このシリーズは,鉄複合体における単分子磁石の振る舞いを理解するためのプラットフォームを提供します.
- 複合体1は,単核転移金属ベースの緩やかな磁気緩和のための新しいベンチマークを表しています.
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