単離可能なシリル基およびゲルミル基が,π結合と結合していない:合成,特徴化,および反応性
Akira Sekiguchi1, Tomohide Fukawa, Masaaki Nakamoto
1Department of Chemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan. sekiguch@staff.chem.tsukuba.ac.jp
Journal of the American Chemical Society
|August 15, 2002
まとめ
研究者は,より重いグループ14の元素から最初の安定したシリルとゲルミルラジカルを合成しました. これらの新種のラジカルは平面幾何学を示し,容易にハロゲン化反応を起こします.
科学分野:
- 有機金属化学 有機金属化学
- シリコン化学 シリコン化学
- ゲルマニウム 化学
背景:
- 安定ラジカルは,反応機構を理解する上で極めて重要です.
- グループ14のより重い元素は,通常,根の安定化のためにpi-bond結合を必要とします.
- ピ安定化が欠けている単離ラジカルは,特に重い元素の場合は稀です.
研究 の 目的:
- ピ結合安定化なしで,より重いグループ14の元素の最初の分離可能なシリルとゲルミルラジカルを合成し,特徴づけること.
- これらの新しい根性種の構造的および電子的性質を調査する.
- ハロゲン化反応におけるこれらのラジカルの反応性を調査する.
主な方法:
- ディクロルゲルミレン-ダイオキサン複合体を用いてトリス[ディ-テルト-ブチル(メチル) シリル]シリルおよび - ゲルミルアニオンの1電子酸化.
- X線結晶学により,原発の分子構造を決定する.
- 電子スピン共振 (ESR) スペクトロスコーピーは,根の性質と超精密結合定数を分析します.
- 様々なアルキルハリドによるハロゲン化反応.
主要な成果:
- 安定したtris[di-tert-butyl(methyl) silyl]silylと-germylラジカル (1と2) の合成に成功しました.
- 結晶構造は,根中心の周りの平面幾何学を明らかにし,sp2ハイブリッド化を示した.
- ESRスペクトルは,小さな超精細結合定数を介して,ラジカルのpi特性を確認しました.
- ラジカル1とラジカル2は,ハロゲン化剤と素早く反応し,相応のハロシランとハロゲルマンを形成した.
結論:
- この研究は,より重いグループ14の元素の最初の分離可能なシリルとゲルミルラジカルを報告し,安定化要件に関する以前の概念に異議を唱える.
- 平面幾何学と根元中心の sp2 混合化は,これらの新種の重要な特徴です.
- これらのラジカルは,ハロゲン化によって新しいオルガノシリコンおよびオルガノゲルマニウム化合物を生成するための貴重なシントンとして機能します.
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