Protolysis of Seven-Membered Zirconacyclocumulene Complexes of Zirconocene
The interaction of the seven-membered zirconacyclocumulene complex Cp2Zr[η4-Me3SiC4(SiMe3)–C(C2SiMe3)=CSiMe3] (1) with an equimolar amount of HCl in dioxane at 20 °C results in the formation of the complex Cp2Zr(Cl)–C(CCSiMe3)C(SiMe3)–C(CCSiMe3)=CH(SiMe3) (4), wherein one of the CC groups...
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Published in | Organometallics Vol. 39; no. 13; pp. 2365 - 2374 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
WASHINGTON
American Chemical Society
13.07.2020
Amer Chemical Soc |
Subjects | |
Online Access | Get full text |
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Summary: | The interaction of the seven-membered zirconacyclocumulene complex Cp2Zr[η4-Me3SiC4(SiMe3)–C(C2SiMe3)=CSiMe3] (1) with an equimolar amount of HCl in dioxane at 20 °C results in the formation of the complex Cp2Zr(Cl)–C(CCSiMe3)C(SiMe3)–C(CCSiMe3)=CH(SiMe3) (4), wherein one of the CC groups is coordinated with the Zr atom. Under similar conditions, the reaction of 1 with an excess of HCl affords Cp2ZrCl2 and a mixture cis,cis- and cis,trans-unsaturated compounds H(Me3Si)CC(C2SiMe3)–C(SiMe3)CH(C2SiMe3) (5) and H(Me3Si)CC(C2SiMe3)–C(SiMe3)C(H)C2SiMe3 (6). The isomeric seven-membered zirconacyclocumulene Cp2Zr[η4-Me3SiC4(SiMe3)–C(SiMe3)C(C2SiMe3)] (2) reacts with 2 equiv of HCl in dioxane to give Cp2ZrCl2, H(Me3SiC2)CC(SiMe3)–C(SiMe3)C(C2SiMe3)H (7), and H(Me3SiC2)CC(SiMe3)–C(SiMe3)CCC(SiMe3)H (8). The subsequent reaction of this mixture with Mg in THF yields zirconabicycles 9 and 10, respectively, containing fused zirconacyclopentadiene and cyclohexadiene rings, and, correspondingly, zirconacyclopentene and cyclopentadiene cycles. From the interaction of 7 with Cp*2ZrCl2 and Mg in THF, complex 11, analogous to 9, was isolated. The protolysis of the seven-membered zirconacyclocumulene Cp2Zr[η4-PhC4(Ph)–(o-C6H4)] (3) with 2 equiv of HCl yields Cp2ZrCl2 and Ph2CC(H)–CCPh (16). The structures of 4, 7, 10, and 11 have been established by X-ray crystallography. The mechanisms of the reactions found are discussed. |
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ISSN: | 0276-7333 1520-6041 |
DOI: | 10.1021/acs.organomet.0c00182 |