Synthesis, hydrosilylation reactivity and catalytic properties of group 4 ansa-metallocene complexes

Santiago Gómez-Ruiz, Sanjiv Prashar*, Mariano Fajardo, Antonio Antiñolo, Antonio Otero, Miguel A. Maestro, Victoria Volkis, Moris S. Eisen, César J. Pastor

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

The following ansa-ligand precursors, Et(H)Si(C5H 5)2 (1), Et(H)Si(C5HMe4)Cl (2), Et(H)Si(C5HMe4)(C5H5) (3), Ph(H)Si(C5HMe4)Cl (4), Ph(H)Si(C5HMe 4)(C5H5) (5), Ph(H)Si(C5HMe 4)2 (6), CH2CHCH2(H)Si(C 5HMe4)Cl (7), CH2CHCH2(H)Si(C 5HMe4)(C5H5) (8), CH 2CHCH2(H)Si(C5HMe4)2 (9), and their lithium derivatives, Li2{Et(H)Si(C5H 4)2} (10), Li2{Et(H)Si(C5Me 4)(C5H4)} (11), Li2{Ph(H)Si(C 5Me4)(C5H4)} (12), Li 2{Ph(H)Si(C5Me4)2} (13), Li 2{CH2CHCH2(H)Si(C5Me 4)(C5H4)} (14) and Li2{CH 2CHCH2(H)Si(C5Me4)2} (15) have been prepared. The group 4 metal complexes, [M{Et(H)Si(η5- C5H4)2}Cl2] (M = Ti (16a), Zr (16b), Hf (16c)), [M{Et(H)Si(η5-C5Me4) (η5-C5H4)}Cl2] (M = Ti (17a), Zr (17b), Hf (17c)), [M{Ph(H)Si(η5-C5Me 4)(η5-C5H4)}Cl2] (M = Ti (18a), Zr (18b), Hf (18c)), [M{Ph(H)Si(η5-C 5Me4)2}Cl2] (M = Ti(19a), Zr (19b), Hf (19c)), M{CH2CHCH2(H)Si(η5-C 5Me4)(η5-C5H4)} Cl2] (M = Ti (20a), Zr (20b)) and [M{CH2CHCH 2(H)Si(η5-C5Me4) 2}Cl2] (M = Ti (21a), Zr (21b), Hf (21c)) were synthesized from the reaction of the lithium ansa-derivatives and the tetrachloride salts of the transition metal. The reactivity of the group 4 metal complexes in hydrosilylation processes has been studied. The reaction of 16b, 17a and 17b with tetravinylsilane gave [Zr{(CH2CH)3SiCH 2CH2(Et)Si(η5-C5H 4)2}Cl2] (22b) and [M{(CH2CH) 3SiCH2CH2(Et)Si(η5-C 5Me4)(η5-C5H4)} Cl2] (M = Ti (23a), Zr (23b)), respectively. The reaction of 17a and 17b with dimethyldivinylsilane yielded the hydrosilylation products [M{(CH 2CH)Me2SiCH2CH2(Et) Si(η5-C5Me4)(η5-C 5H4)}Cl2] (M = Ti (24a), Zr (24b)), respectively. 23b and 24b reacted with the silane reagent HSiEt3 to form, via hydrosilylation, [Zr{(Et3SiCH2CH 2)3SiCH2CH2(Et)Si(η5- C5Me4)(η5-C5H 4)}Cl2] (25b) and [Zr{(Et3SiCH 2CH2)Me2SiCH2CH2(Et) Si(η5-C5Me4)(η5-C 5H4)}Cl2] (26b), respectively. The previously synthesized compounds, [M{CH2CH(Me)Si(η5-C 5Me4)2}Cl2] (M = Ti (27a), Zr (27b)) and [Zr{CH2CHCH2(Me)Si(η5-C 5Me4)2}Cl2] (28b), have also been tested in reactions of hydrosilylation with SiHMeCl2 to give [M{Cl2MeSiCH2CH2(Me)Si(η5- C5Me4)2}Cl2] (M = Ti (29a), Zr (29b)) and [Zr{Cl2MeSiCH2CH2CH 2(Me)Si(η5-C5Me4) 2}Cl2] (30b). All the zirconocene compounds are active to varying degrees as catalysts in the polymerization of ethylene. The molecular structures of 21b and 21c have been determined by single crystal X-ray diffraction studies.

Original languageEnglish
Pages (from-to)1298-1313
Number of pages16
JournalPolyhedron
Volume24
Issue number11
DOIs
StatePublished - 4 Aug 2005
Externally publishedYes

Keywords

  • Hafnium
  • Hydrosilylation
  • Polymerization
  • Titanium
  • Zirconium
  • ansa-Metallocene complexes

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