Scandium Phosphonioketene: Synthesis,Bonding and Reactivity |
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Authors: | Weiqing Mao Yaya Wang Dr. Li Xiang Prof. Dr. Qian Peng Dr. Xuebing Leng Prof. Dr. Yaofeng Chen |
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Affiliation: | 1. State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032 P. R. China;2. State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071 P. R. China |
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Abstract: | Reaction of a scandium phosphoniomethylidene with carbon monoxide provides the first scandium phosphonioketene ( 1 ). X-ray diffraction analysis shows that the complex has a very short Sc−C bond (2.138(2) Å), and DFT calculations indicate that this unusual short bond length is due to the significant contribution of ionic coulomb interaction between carbon and scandium and the η2-O,C coordination fashion. Complex 1 is thermally stable, albeit shows high reactivity towards a series of unsaturated substrates, including carbon dioxide, ketone, imine, nitrile and isocyanide. In the reaction with tert-butyl isocyanide, not only an insertion of tert-butyl isocyanide into the Sc−C bond occur, but also a C−H activation on the phenyl ring. DFT calculations show that the reactivity of 1 operated by nucleophilic properties, and therefore the reaction mechanism favors the nucleophilic attack to isocyanide as a rate-determining step, followed by the stepwise C−H activation through an interesting C−H deprotonation. |
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Keywords: | carbon monoxide density functional calculations insertion reaction ketenes scandium |
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