水素鉄による素早い水素原子抽出 ((III) ポルフィラジン
1Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States.
Journal of the American Chemical Society
|March 2, 2017
まとめ
新しいヒドロキソフェル型ポルフィラジン複合体は,C−H原子移転に対して非常に高い反応性を示しています. この鉄複合体は,化学的変換において他の鉄酸化物とフェリル複合体を大幅に上回る急速な反応速度を示している.
科学分野:
- 無機化学
- バイオ有機化学
- 協調化学
背景:
- 鉄のポルフィラジン複合体は,触媒と生物学的システムにおいて不可欠である.
- 高価鉄酸化/水酸化種の反応性を理解することは,触媒メカニズムにとって極めて重要です.
- 以前の鉄複合体は,しばしばC−H結合の活性化に制限がある.
研究 の 目的:
- 反応性のある水素フェルポルフィラジン複合体を合成し特徴づけること.
- 複合体の電気化学的性質と再酸化可能性を調査する.
- C−H原子移転反応における複合体の触媒活性を評価する.
主な方法:
- 鉄と鉄性ポルフィラジン複合体の合成
- サイクル電圧測定を含む電気化学分析
- 水素原子の異なった基質との移動反応の運動研究.
主要な成果:
- 安定したヒドロキソフェリック・ポルフィラジン複合体である[PyPz) FeIII (OH2) ]4+を成功裏に製造した.
- 複合体は,高いFeIII-OH/FeII-OH2の還元ポテンシャル (pH5.2で680mV) を示し,広範囲のpHでネルンシュタインの振る舞いを示した.
- この複合体は,知られている鉄複合体を大幅に上回る2.22 × 10 3 M 1 s 1 の二次速度定数で,急速なC-H原子移転を示した.
結論:
- 合成されたヒドロキソフェルポルフィラジン複合体は,効率的なC−H原子移転を可能にする非常に強力な酸化物質である.
- その驚くべき反応性は,高い還元能力と好ましいO-H結合解離エネルギーから生じる.
- この複合体は,酸化反応のための非常に活性な鉄ベースの触媒の開発における重要な進歩を表しています.
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