CpCr[(ArNCMe) 2CH](R) 複合体によるクロム (((III) -アルキル結合の同解を探求する
K Cory MacLeod1, Julia L Conway, Brian O Patrick
1Department of Chemistry, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC, Canada V1V 1V7.
Journal of the American Chemical Society
|November 13, 2010
まとめ
研究者は,R群がクロミウム-R結合同解をどのように影響するかを研究するために,パラマグネティッククロミウム (III) モノヒドロカルビル複合体を合成した. R群のステリックおよび電子的要因は結合強度と反応性に影響を与え,いくつかの複合体はホモリシスを経験し,他の複合体は光分解によって反応します.
科学分野:
- 有機金属化学 有機金属化学
- 協調化化学について
- 反応メカニズム 反応メカニズム
背景:
- パラマグネティッククロミウム (III) モノヒドロカルビル複合体は,金属-炭素結合の反応性を理解する上で興味深いものです.
- 有機リガンドの異なるステリックおよび電子性質が,金属-炭素結合の同解に及ぼす影響は,完全に理解されていません.
研究 の 目的:
- 一連のパラマグネティッククロム (III) モノヒドロカルビル複合体,CpCr (ArNCMe) 2CH (R) を合成する.
- 様々なR群 (主アルキル,ベンジル,フェニル,アルケニル,アルキニル) がCr-R結合同解への傾向に及ぼす影響を調査する.
- これらのクロム複合体の代替合成経路を探求する.
主な方法:
- CpCr[(ArNCMe) 2CH](Cl) の塩のメタテシスによる複合体の合成,グリニャード反応剤またはオルゴノリチウム化合物による.
- Cr (II) の前駆体および原発源を用いた代替ルートの探査.
- 特徴は,UV-VISスペクトロスコピーと単結晶X線微分法を用いて決定した.
- 紫外線対光スペクトロスコーピーを用いたCr-R結合ホモリシスとディフェニル二硫化物 (PhSSPh) との反応の運動学的研究.
主要な成果:
- 紫外線スペクトルは,Cr (III) -R化合物の特徴的な帯を示し,最大値は約395-436 nmと535-582 nmでした.
- X線 difraktionにより,通常2.10-2.13 Åの間のCr-CH2R結合長が明らかになり,Rグループ (ベンジルでは長,アルケニル/アルキニルでは短) に基づく変動がありました.
- 室温でのCr-R結合の同解速度は,Rグループと有意に変化した;ネオペンチル,ベンジル,イソブチル複合体は測定可能な同解を示したが,他の複合体は光分解によってCpCr[(ArNCMe) 2CH](SPh) にクリーン変換した.
結論:
- Rグループのステリックと電子の性質は,Cr-R結合強度と同解分裂傾向に大きな影響を与える.
- 異なるR群は,熱同解および光化学的に誘発されたC-S結合形成を含む,異なる反応経路につながります.
- この研究は,パラ磁性クロム複合体における金属-炭素結合の安定性と反応性を支配する要因についての洞察を提供します.
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