リュテニウムベンジリデン複合体による原子移転の原始反応におけるインシチュー触媒変化

Juneyoung Lee¹, Jessica M Grandner², Keary M Engle¹

¹Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.

Journal of the American Chemical Society

|May 18, 2016

まとめ

ルテニウムベンジリデン複合体は,原子移転ラジカル (ATR) 反応のための新しい活性種に変容する. ATRPやATRAのようなATR反応を触媒化する.

科学分野:

有機金属化学
カタリシス
ポリマー化学

背景:

ルテニウムベンジリデン複合体は,オレフィン転化触媒として確立されている.
これらの複合体は,原子移転基 (ATR) 反応,原子移転基加法 (ATRA) および原子移転基ポリメリゼーション (ATRP) の活動も示しています.
ATR反応におけるルテニウムベンジリデン複合体の触媒的メカニズムは,よく研究されたオレフィン転移メカニズムとは異なり,十分に理解されていません.

研究の目的:

ルテニウムベンジリデン複合体がATR反応を触媒化するメカニズムを調査する.
ATRの反応に責任のある活性な触媒種を特定する.
様々なルテニウムベンジリデン複合体のATR活性を比較する.

主な方法:

反応の進行と種の変異を監視するために1H NMRスペクトロスコーピーを用いた運動研究.
7つの異なるルテニウムベンジリデン複合体の分析
1H,13C,31P NMRスペクトロスコーピー,X線結晶学を含むメカニズム学および計算学的研究.

主要な成果:

ルテニウムベンジリデンの複合体は,ATRA条件下で急速に新しい,転移不活性な種に変換されます.
ルテニウムベンジリデンの複合体の前活性化により,低温でもATRAの運動反応性が強化されます.
ATRPを効果的に触媒化するのは,容易にATRA活性種に変容する複合体だけであり,他の複合体は,酸化還元誘発ポリメリゼーションを好む.
ATR反応の活性触媒は, in situ で形成される転化不活性ルテニウム種である.

結論:

ルテニウムで触媒化されたATR反応の活性触媒は, in situで生成され,メタテシスで不活性なルテニウム種である.
この種は,元のルテニウムベンジリデン複合体とは異なる.
構造分析は,活性種がRuxCly ((PCy3) z複合体である可能性があることを示唆している.

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