Synthesis and N鈥揌 Reductive Elimination Study of Dinuclear Ruthenium Imido Dihydride Complexes
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- 作者：Shin Takemoto ; Yusuke Yamazaki ; Takahiro Yamano ; Daichi Mashima ; Hiroyuki Matsuzaka
- 刊名：The Journal of the American Chemical Society
- 出版年：2012
- 出版时间：October 17, 2012
- 年：2012
- 卷：134
- 期：41
- 页码：17027-17035
- 全文大小：577K
- 年卷期：v.134,no.41(October 17, 2012)
- ISSN：1520-5126
文摘
Diruthenium imido dihydride complexes [(Cp*Ru)2(渭-NAr)(渭-H)2] (Ar = Ph (2a), p-MeOC6H4 (2b), p-ClC6H4 (2c), 2,6-Me2C6H3 (2d); Cp* = 畏5-C5Me5) have been synthesized by hydrogenation of the corresponding bis(amido) complexes [Cp*Ru(渭-NHAr)]2 (1a鈥?b>d). Reductive elimination of the N鈥揌 bond from 2a鈥?b>c in the presence of arene yields the amido hydride complexes [(Cp*Ru)2(渭-NHAr)(渭-H)(渭-畏2:畏2-arene)] containing a 蟺-bound arene. The rate and kinetic isotope effect for this reaction are consistent with a mechanism involving initial rate-determining reductive elimination of an N鈥揌 bond to produce the coordinatively unsaturated amido hydride species {(Cp*Ru)2(渭-NHAr)(渭-H)} (A) followed by rapid trapping of this species by an arene. The existence of A is also supported by the reversible interconversion of [(Cp*Ru)2(渭-NHPh)(渭-H)(渭-畏2:畏2-C7H8)] with the tetranuclear complex [(Cp*Ru)4(渭4-NHPh)(渭-NHPh)(渭-H)2] (4), a dimerization product of A through a 渭4-NHPh bridge. DFT calculations provide structures of A and transition states for the N鈥揌 reductive elimination. Two distinct reaction pathways are found for the N鈥揌 reductive elimination, one of which involves direct migration of a 渭-hydride to the 渭-NAr ligand, and the other involves formation of a transient terminal hydride species.