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Showing 1 to 16 of 16 for “"Zirconocene"”.
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Tandem reaction sequences on a zirconocene template
… the cis-bicyclo[3.3.0]oct-2-ene skeleton. Zirconocene mediated co-cyclisation of 1,6-enynes provides unsaturated 5-membered zirconacycles which are homologated to 6-membered zirconacycles by insertion of 1,1-dihalo-1-lithio species (dihalogenocarbenoids). Further rearrangement to a novel …
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Synthesis of indoles via zirconocene-stabilized benzyne complexes
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1994.
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Some synthetic applications of 3,4-disubstituted indoles generated via zirconocene-stabilized benzyne complexes
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1997.
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The Use of Functionalized Zirconocenes as Precursors to Silica-Supported Zirconocene Olefin Polymerization Catalysts
… the synthesis of electrophile-functionalized zirconocene dihalide complexes and the use of functionalized zirconocene dihalides as precursors to silica-supported metallocene olefin polymerization catalysts. Our first objective was to extend the metallocene "functionalization" chemistry to …
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Exploration of mild and selective hydrozirconation reactions facilitated by zirconocene hydride catalysts generated in Situ.
… conditions that facilitate the conversion of oxozirconocenes to ZrH catalysts using hydrosilanes and (ii) identitfy a mild strategy for the preparation of a ZrH catalyst using Cp2ZrCl2 as a precatalyst. After establishing a general platform for ZrH catalyst generation and its efficient turnover, …
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Zirconocene-Mediated Carbonylative Coupling of Grignard Reagents and Cancer Prevention via Compounds that Modulate 15-PGDH
… coupling of Grignard reagents using organozirconocene intermediates. Organozirconocenes are versatile synthetic intermediates that can undergo carbonylation to yield acyl anion equivalents. Zirconocene hydrochloride is often the reagent of choice for accessing these intermediates but …
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Carbenoid insertions and cyclometallations of zirconacycles
… a novel endocyclic cyclometallation to afford a zirconocene n2-alkene<br/>complex followed by decomplexation. A wide variety of zirconacyclopentenes and<br/>benzyl carbenoids have been investigated.<br/><br/>A range of benzyl carbenoids were inserted into a zirconacyclopentane to afford …
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Manganese-catalyzed carbonylation of alkyl iodides
… cross-coupling of aryl bromides with zirconocene-benzyne complexes has been investigated by S.L. Buchwald and coworkers. This method allows the formation of substituted biphenyls and terphenyls, however only two ortho-substituents are tolerated in this transformation. The studies …
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Synthesis of multicomponent heavy alkali metal amide systems and extensions to zirconium chemistry
… with the solid and solution state studies of zirconocene species combined with alkali metal and alkali earth metal amides obtained during this work.Chapter 2 includes a deep discussion in the solid state of NaHMDS systems capturing Na halide units in the presence of a multidentate Lewis base …
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Mononuclear and Dinuclear Complexes of Allylated alpha-Diimines as Catalysts for the Polymerization of Ethylene
… bearing allyl groups were coupled with a bridged zirconocene complex possessing a hydride silane moiety via hydrosilylation reaction in the presence of Karstedts catalyst to afford five new dinuclear precursors. These dinuclear precursors were activated with methylalumoxane (MAO) and tested for …
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Transition path sampling in organometallic catalysis: Overcoming the rare event problem in ab initio molecular dynamics
… transfer chain termination reaction of a zirconocene polymerization catalyst. The reaction dynamics showed that the barder of the e-hydrogen transfer is atypically flat due to a Zr---H interaction in the transition state. We subsequently used AIMD to study the equilibrium structure and …
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Synthesis, Properties, and Reactivity of Pentafluorophenyl Substituted Cyclopentadienes and Their Transition Metal Complexes
… are conducted using C6F5- and C6H5-substituted zirconocene dichlorides as catalysts. Contrary to findings published elsewhere, this study shows that substituent electronic effects induce substantial changes in comonomer incorporation.
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Synthesis of Group (lV) Transition Metal Complexes and their Applications as Catalysts for Ethylene Polymerization
… between alkoxy group and indenyl ligand of the zirconocene dichloride complex as well as the steric bulk of the alkoxy substituent. The activity maximum (27467 kg PE/mol cat. h) was found for a chain length of four carbon atoms. Further increase or decrease in the chain length resulted in a …
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Synthesis of Bridged and Unbridged Group (lV) Metallocene Complexes as Catalyst Precursors for Ethylene Polymerization
… both complexes exhibited high activities. The zirconocene catalyst 34 showed a higher activity (7610 kg PE/mol cat. h) compared to the hafnium catalyst 35 (3590 kg PE/mol cat. h). A second type of ansa-metallocene complexes was synthesized and tested in the homogeneous polymerization of …
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Nanocomposites: Incorporation of Cellulose Nanocrystals into Polymers and Addition of Zwitterionic Functionality
… The catalyst 1,1'-bis(bromodimethylsilyl)zirconocene dibromide (catalyst 1) is equipped with anchoring groups that are capable of attachment to the surface hydroxyl groups of CNC particles. After immobilizing catalyst 1 onto various CNC samples, introduction of solvent, organoaluminum …