Exploring the Mechanism of Aqueous C−H Activation by Pt(II) through Model Chemistry: Evidence for the Intermediacy of Alkylhydridoplatinum(IV) and Alkane σ-Adducts
Exploring the Mechanism of Aqueous C−H Activation by Pt(II) through Model Chemistry: Evidence for the Intermediacy of Alkylhydridoplatinum(IV) and Alkane σ-Adducts
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通过模型化学探索 Pt(II) 水相 C−H 活化机制：烷基氢化铂 (IV) 和烷烃 σ-加合物中间体的证据
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发表时间：
1996
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通讯作者：
J. Bercaw
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作者：
S. Stahl;J. Labinger;J. Bercaw
本文研究了几种烷基铂（Ⅱ）配合物[（tmeda）PtMeCl（2）（tmeda = N，N，N '，N'-四甲基乙二胺），（tmeda）Pt（CH_2 Ph）Cl（5），（tmeda）PtMe_2（11）和trans-（PEt_3）_2 Pt（CH_3）Cl（15）]在CD_2Cl_2和CD_3 OD中的质子分解机理。这些反应模拟了Pt（II）水溶液活化C-H的微观逆转。四个系统中的每一个（2个在CD 3 OD中，5个在CD 2Cl 2中，11个在CD 3 OD中，和15个在CD 3 OD中）在质子分解反应中表现出不同的行为，如通过低温1H NMR光谱所观察到的。2在甲醇-d4中的质子分解没有观察到中间体。5和HCl在CD 2Cl 2中在−78 °C下发生可逆反应，生成（tmeda）Pt（CH 2 Ph）（H）Cl 2（6），在较高温度下发生甲苯还原消除。在-78 °C下用HCl在甲醇中处理11产生（tmeda）PtMe 2（H）Cl（12），其在还原消除甲烷之前将来自溶剂（CD 3 OD）的氘结合到甲基中。最后，15在甲醇中与H+反应，释放出甲基。
The protonolysis mechanisms of several alkylplatinum(II) complexes [(tmeda)PtMeCl (2) (tmeda = N,N,N‘,N‘-tetramethylethylenediamine), (tmeda)Pt(CH2Ph)Cl (5), (tmeda)PtMe2 (11), and trans-(PEt3)2Pt(CH3)Cl (15)] in CD2Cl2 and CD3OD have been investigated. These reactions model the microscopic reverse of C−H activation by aqueous Pt(II). Each of the four systems (2 in CD3OD, 5 in CD2Cl2, 11 in CD3OD, and 15 in CD3OD) exhibits different behavior in the protonolysis reaction as observed by low-temperature 1H NMR spectroscopy. Protonolysis of 2 in methanol-d4 proceeds with no observable intermediates. Reversible reaction between 5 and HCl in CD2Cl2 at −78 °C produces (tmeda)Pt(CH2Ph)(H)Cl2 (6), which undergoes reductive elimination of toluene at higher temperatures. Treatment of 11 with HCl in methanol at −78 °C generates (tmeda)PtMe2(H)Cl (12), which incorporates deuterium from solvent (CD3OD) into the methyl groups prior to reductive elimination of methane. Finally, 15 reacts with H+ in methanol to liberate m...