Alkane Dehydrogenation by Sequential, Double C-H Bond Activation by TpBr3Ir(C2H4)2 (TpBr3 = hydrotris(3,4,5-tribromo)pyrazolylborate)
详细信息 查看全文
- 作者：Pilar Rodrí ; guez ; M. Mar Dí ; az-Requejo ; Tomá ; s R. Belderrain ; Swiatoslaw Trofimenko ; M. Carmen Nicasio ; and Pedro J. Pé ; rez
- 刊名：Organometallics
- 出版年：2004
- 出版时间：April 26, 2004
- 年：2004
- 卷：23
- 期：9
- 页码：2162 - 2167
- 全文大小：94K
- 年卷期：v.23,no.9(April 26, 2004)
- ISSN：1520-6041
文摘
The new complex TpBr3Ir(C2H4)2, 1, photochemically activates the C-H bonds of n-pentanein a two-step process, the first one being the formation of an isolable alkyl-hydrideintermediate of composition TpBr3Ir(H)(C2H4)(C5H11), 3a, that subsequently undergoes
-hydride elimination to generate a terminal olefin complex, TpBr3Ir(H)2(C5H10), 4a. Thereaction can also be extended to diethyl ether. In this case, the reaction proceeds by theactivation of one of the -C-H bonds (with respect to the O-ether atom) with formation ofthe alkyl-hydride 3b and the dehydrogenation product 4b. These processes also competewith the intramolecular C-H activation of one of the coordinated ethylene ligand by theIr(I) center in 1, which affords the hydride-vinyl complex TpBr3Ir(H)(CH=CH2)(C2H4), 2.Attempts to thermally induce the above transformations has led to the exclusive formationof a mixture of the hydride-
pha.gif" BORDER=0>,
-butenyl complex TpBr3Ir(H)(CH2CH2CH=CH2), 5, and thehydride-crotyl complex TpBr3Ir(H)(C4H7), 6.
-hydride elimination to generate a terminal olefin complex, TpBr3Ir(H)2(C5H10), 4a. Thereaction can also be extended to diethyl ether. In this case, the reaction proceeds by theactivation of one of the -C-H bonds (with respect to the O-ether atom) with formation ofthe alkyl-hydride 3b and the dehydrogenation product 4b. These processes also competewith the intramolecular C-H activation of one of the coordinated ethylene ligand by theIr(I) center in 1, which affords the hydride-vinyl complex TpBr3Ir(H)(CH=CH2)(C2H4), 2.Attempts to thermally induce the above transformations has led to the exclusive formationof a mixture of the hydride-pha.gif" BORDER=0>,-butenyl complex TpBr3Ir(H)(CH2CH2CH=CH2), 5, and thehydride-crotyl complex TpBr3Ir(H)(C4H7), 6.