Amine catalyzed solvent C-H bond activation as deactivation route for cationic decamethylzirconocene olefin polymerization catalysts.
نویسندگان
چکیده
The C-D activation of bromobenzene-d(5) by [Cp*(2)ZrMe(BrC(6)D(5)-kappaBr)][B(C(6)F(5))(4)] to form sigma-aryl complex [Cp*(2)Zr(2-BrC(6)D(4)-kappa(2)Br,C)][B(C(6)F(5))(4)] is accelerated when the decamethylzirconocene methyl cation is generated in the presence of tertiary amines. Computational studies suggest that the overall sigma-bond metathesis reaction proceeds, in the presence of tertiary amines, via initial deprotonation of bromobenzene in the coordination sphere of the metal center. In a subsequent step, the resulting neutral methyl aryl species, Cp*(2)ZrMe(2-BrC(6)D(4)), reacts with the concurrently generated trialkylammonium cation to generate [Cp*(2)Zr(2-BrC(6)D(4)-kappa(2)Br,C)][B(C(6)F(5))(4)].
منابع مشابه
Evidence of Fluoride Transfer from the Anion of [Zr[lcub]C5H3[SiMe2([eta]1-NtBu)]2[rcub]]+[RB(C6F5)3][minus] Complexes to the Zirconocenium CationFinancial support by the Spanish MEC (project MAT2004-02614) and DGUI/CM (program S/0505/PPQ-0328) is acknowleged. R[equals]Me, CH2Ph
generated by activation of the corresponding dialkyl compounds with B(C6F5)3 are active homogeneous catalysts for olefin polymerization. Weakly coordinating anions are required to minimize the ion-pairing interactions, which are crucial in determining the properties of the resulting polymeric materials and the characteristics of the polymerization processes. These counteranions frequently conta...
متن کاملMechanistic Investigation on Scandium-Catalyzed C−H Addition of Pyridines to Olefins
This paper reports computational studies on the ortho alkylation of pyridines via C−H addition to olefins catalyzed by cationic half-sandwich rare-earth alkyl species. A detailed mechanism concerning the generation of catalytically active species and C−H addition has been computationally investigated at the molecular and electronic levels. The results support the mechanism based on experiments,...
متن کاملBis(benzimidazole)amine vanadium catalysts for olefin polymerisation and co-polymerisation: thermally robust, single-site catalysts activated by simple alkylaluminium reagents.
Vanadium complexes containing bis(benzimidazole)amine ligands, upon activation by simple alkylaluminium reagents, give unusually robust, single-site, catalysts for olefin polymerisation/co-polymerisation.
متن کاملComparing families of olefin polymerization precatalysts using the percentage of buried volume.
We report a systematic comparison of the steric properties of different stereoselective olefin polymerization catalysts using the percentage of buried volume, %V(Bur), as a molecular descriptor. For the first time, isoselective and syndioselective group 4 metallocenes are compared with group 4 isoselective phenoxy-amine and group 4 syndioselective phenoxy-imine catalysts using the same molecula...
متن کاملRuthenium-based heterocyclic carbene-coordinated olefin metathesis catalysts.
The fascinating story of olefin (or alkene) metathesis (eq 1) began almost five decades ago, when Anderson and Merckling reported the first carbon-carbon double-bond rearrangement reaction in the titanium-catalyzed polymerization of norbornene.1 Nine years later, Banks and Bailey reported “a new disproportionation reaction . . . in which olefins are converted to homologues of shorter and longer...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of the American Chemical Society
دوره 131 46 شماره
صفحات -
تاریخ انتشار 2009