New ligand environments for soluble Zieglernatta olefin polymerization catalyst precursors. X-ray structures of

Ying Mu, Warren E. Piers, Leonard R. Macgillivray, Michael J. Zaworotko

Research output: Contribution to journalArticlepeer-review

Abstract

Treatment of dimethyl(tetramethylcyclopentadieny)chloro silane with S-(-) pyrolidine methanol provided the O-silylated ligand(C5Me4H)SiMe2OCH2(C4H7NH), 1, (Cp*SiProH2) as a 90% pure, thermally unstable oil in 65% yield. Reaction of 1 with Zr(NMe2)4 resulted in attachment of 1 to the zirconium center with elimination of HNMe2, yielding (Cp*SiPro)Zr(NMe2)2, 2, as a viscous oil in high yield (95%). Compound 2 was converted to the trichloride derivative (Cp*SiProH)ZrCl3, 3, in 75% yield by treatment with three equivalents of HCl·HNMe2: compound is a mixture of diastereomers; the major species was characterized by X-ray crystallography, revealing a Cp*ON coordination mode for the Cp*SiProH ligand. (3: orthorhombic; space group P212121, a = 10.0009(13), b = 12.7597(12), c = 16.2749(15) Å, V=2076.8(4) Å3, Z = 4, R = 0.043, rw = 0.041.) Deprotonation of 3 (diastereomeric mixture) with LiN(SiMe3)2 produced the dichloride (Cp*SiPro)ZrCl2, 4, in 71% yield. Alkylation of either 3 or 4 resulted in SiO bond cleavage in the Cp*SiPro ligand and gave a dimeric complex 5 which was characterized by X-ray crystallograhy. (5: monoclinic, space group P21, a = 9.1285(10), b = 20.2197(22), c = 11.0214(14) A ̊, β = 90.38(7)°, V = 2034.2(4) A ̊3, Z = 2, R = 0.040, Rw = 0.042. Limited ethylene polymerization activity was observed for 3 and 4 in the presence of MAO co-catalyst.

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalPolyhedron
Volume14
Issue number1
DOIs
Publication statusPublished - Jan 1995
Externally publishedYes

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