Yttrium Complexes Featuring Different Y鈥揅 Bonds. Comparative Reactivity Studies: Toward Terminal Imido Complexes
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- 作者：Alexander A. Karpov ; Anton V. Cherkasov ; Georgy K. Fukin ; Andrei S. Shavyrin ; Lapo Luconi ; Giuliano Giambastiani ; Alexander A. Trifonov
- 刊名：Organometallics
- 出版年：2013
- 出版时间：April 22, 2013
- 年：2013
- 卷：32
- 期：8
- 页码：2379-2388
- 全文大小：399K
- 年卷期：v.32,no.8(April 22, 2013)
- ISSN：1520-6041
文摘
The reactions of 2,6-diisopropylaniline with equimolar amounts of alkyl鈥揾eteroaryl yttrium complexes containing Y鈥揅(sp3, alkyl) along with Y鈥揅(sp2, heteroaryl) bonds resulting from intramolecular C鈥揌 bond activation of the amido鈥損yridinate ligands [NNOBzFur]YCH2SiMe3(THF)2, [NNSBzTh]YCH2SiMe3(THF)2, and [NNSEtTh]YCH2SiMe3(THF)2 have been scrutinized with the aim of synthesizing yttrium terminal imido species. These reactions occur at ambient temperature with the protonolysis of the Y鈥揅(sp3, alkyl) bond, thus affording anilido鈥揾eteroaryl species and maintaining the residual Y鈥揅(sp2, heteroaryl) bond untouched. However, the subsequent transformation of the as-synthesized anilido鈥揾eteroaryl complexes depends on the nature of the substituent on the 6-position of the pyridyl ring. In the case of the benzofuryl yttrium derivative [NNOBzFur]YNH-2,6-iPr2C6H3(THF)2 (4), heating to 50 掳C results in benzofuran ring opening with the formation of an anilido species supported by a dianionic amido鈥搚ne鈥損henolate ligand framework, [NNC鈮O]YNH-2,6-iPr2C6H3(THF) (6). In contrast, a complex containing a benzothiophenyl moiety, [NNSBzTh]YNH-2,6-iPr2C6H3(THF)2 (7), slowly undergoes protonation of the Y鈥揅(sp2, heteroaryl) bond and a ligand redistribution reaction takes place, affording an yttrium bis(anilido) species supported by a monoanionic amido鈥損yridinate ligand featuring intramolecular Y鈥揝 heteroaryl coordination, [NNSBzTh]Y[NH-2,6-iPr2C6H3]2 (9). It is worth noting that an yttrium complex containing 伪-thiophenyl fragment, [NNSEtTh]YNH-2,6-iPr2C6H3(THF)2 (10), turned out to be extraordinarily robust and no transformation was ever detected even upon heating the complex at 100 掳C for prolonged times.