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Title: Model Ziegler-Natta [alpha]-olefin polymerization catalysts derived from [([eta][sup 5]-C[sub 5]Me[sub 4]) SiMe[sub 2] ([eta][sup 1]-NCMe[sub 3])(PMe[sub 3])Sc([mu][sub 2]-H)][sub 2] and [([eta][sup 5]-C[sub 5]Me[sub 4] SiMe[sub 2]([eta][sup 1]-NCMe[sub 3])) Sc([mu][sub 2]CH[sub 2]CH[sub 2]CH[sub 3])][sub 2]. Synthesis, structures, and kinetic and equilibrium investigations of the catalytically active species in solution

Abstract

The scandium hydride complex [(Cp*SiNR)(PMe[sub 3])Sc([mu]-H)][sub 2], (1) ((Cp*SiNR) = (([eta][sup 5]-C[sub 5]Me[sub 4])SiMe[sub 2]([eta][sup 1]-NCMe[sub 3]))) is prepared by hydrogenation of (Cp*SiNR)ScCH(SiMe[sub 3])[sub 2] in the presence of trimethylphosphine. The hydride complex is a catalyst precursor for the polymerization of [alpha]-olefins, yielding atactic products of low molecular weight (M[sub n] = 3000-7000). GC/MS analysis of volatile, oligomeric products revealed that all scandium centers are active during the polymerization. Selectivity for head-to-tail insertion is high (> 99%) and for the tetramer, pentamer, and hexamer formed during propene polymerization, the maximum theoretical numbers of head-to-tail stereoisomers are observed by capillary GC. The stoichiometric reaction between 1 and 2 equiv of ethylene produces the unusual ethylene-bridged dimer [(Cp*SiNR)(PMe[sub 3])Sc][sub 2]([mu], [eta][sup 2]-C[sub 2]H[sub 4]) (2) and an equivalent of ethane, whereas the same reaction with propene affords the phosphine-free, alkyl-bridged scandium dimer [(Cp*SiNR)Sc][sub 2]([mu]-CH[sub 2]CH[sub 2]CH[sub 3])[sub 2] (3). The absence of coordinating phosphine allows the latter complex to function as a more active olefin polymerization catalyst precursor. 1 reacts with styrene to form a unique double-insertion product arising from sequential 1,2- and 2,1-styrene insertion. 41 refs., 13 figs., 9 tabs.

Authors:
; ; ; ;  [1]
  1. California Inst. of Technology, Pasadena, CA (United States)
Publication Date:
OSTI Identifier:
7069751
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society; (United States)
Additional Journal Information:
Journal Volume: 116:11; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALKENES; POLYMERIZATION; SCANDIUM COMPLEXES; MOLECULAR STRUCTURE; SYNTHESIS; ZIEGLER CATALYST; EQUILIBRIUM; ETHYLENE; EXPERIMENTAL DATA; GAS CHROMATOGRAPHY; HYDRIDES; HYDROGENATION; MASS SPECTROSCOPY; NUCLEAR MAGNETIC RESONANCE; PHOSPHINES; SILICON COMPOUNDS; THEORETICAL DATA; X-RAY DIFFRACTION; CATALYSTS; CHEMICAL REACTIONS; CHROMATOGRAPHY; COHERENT SCATTERING; COMPLEXES; DATA; DIFFRACTION; HYDROCARBONS; HYDROGEN COMPOUNDS; INFORMATION; MAGNETIC RESONANCE; NUMERICAL DATA; ORGANIC COMPOUNDS; PHOSPHORUS COMPOUNDS; RESONANCE; SCATTERING; SEPARATION PROCESSES; SPECTROSCOPY; TRANSITION ELEMENT COMPLEXES; 400201* - Chemical & Physicochemical Properties; 400102 - Chemical & Spectral Procedures

Citation Formats

Shapiro, P J, Cotter, W D, Schaefer, W P, Labinger, J A, and Bercaw, J E. Model Ziegler-Natta [alpha]-olefin polymerization catalysts derived from [([eta][sup 5]-C[sub 5]Me[sub 4]) SiMe[sub 2] ([eta][sup 1]-NCMe[sub 3])(PMe[sub 3])Sc([mu][sub 2]-H)][sub 2] and [([eta][sup 5]-C[sub 5]Me[sub 4] SiMe[sub 2]([eta][sup 1]-NCMe[sub 3])) Sc([mu][sub 2]CH[sub 2]CH[sub 2]CH[sub 3])][sub 2]. Synthesis, structures, and kinetic and equilibrium investigations of the catalytically active species in solution. United States: N. p., 1994. Web. doi:10.1021/ja00090a011.
Shapiro, P J, Cotter, W D, Schaefer, W P, Labinger, J A, & Bercaw, J E. Model Ziegler-Natta [alpha]-olefin polymerization catalysts derived from [([eta][sup 5]-C[sub 5]Me[sub 4]) SiMe[sub 2] ([eta][sup 1]-NCMe[sub 3])(PMe[sub 3])Sc([mu][sub 2]-H)][sub 2] and [([eta][sup 5]-C[sub 5]Me[sub 4] SiMe[sub 2]([eta][sup 1]-NCMe[sub 3])) Sc([mu][sub 2]CH[sub 2]CH[sub 2]CH[sub 3])][sub 2]. Synthesis, structures, and kinetic and equilibrium investigations of the catalytically active species in solution. United States. https://doi.org/10.1021/ja00090a011
Shapiro, P J, Cotter, W D, Schaefer, W P, Labinger, J A, and Bercaw, J E. 1994. "Model Ziegler-Natta [alpha]-olefin polymerization catalysts derived from [([eta][sup 5]-C[sub 5]Me[sub 4]) SiMe[sub 2] ([eta][sup 1]-NCMe[sub 3])(PMe[sub 3])Sc([mu][sub 2]-H)][sub 2] and [([eta][sup 5]-C[sub 5]Me[sub 4] SiMe[sub 2]([eta][sup 1]-NCMe[sub 3])) Sc([mu][sub 2]CH[sub 2]CH[sub 2]CH[sub 3])][sub 2]. Synthesis, structures, and kinetic and equilibrium investigations of the catalytically active species in solution". United States. https://doi.org/10.1021/ja00090a011.
@article{osti_7069751,
title = {Model Ziegler-Natta [alpha]-olefin polymerization catalysts derived from [([eta][sup 5]-C[sub 5]Me[sub 4]) SiMe[sub 2] ([eta][sup 1]-NCMe[sub 3])(PMe[sub 3])Sc([mu][sub 2]-H)][sub 2] and [([eta][sup 5]-C[sub 5]Me[sub 4] SiMe[sub 2]([eta][sup 1]-NCMe[sub 3])) Sc([mu][sub 2]CH[sub 2]CH[sub 2]CH[sub 3])][sub 2]. Synthesis, structures, and kinetic and equilibrium investigations of the catalytically active species in solution},
author = {Shapiro, P J and Cotter, W D and Schaefer, W P and Labinger, J A and Bercaw, J E},
abstractNote = {The scandium hydride complex [(Cp*SiNR)(PMe[sub 3])Sc([mu]-H)][sub 2], (1) ((Cp*SiNR) = (([eta][sup 5]-C[sub 5]Me[sub 4])SiMe[sub 2]([eta][sup 1]-NCMe[sub 3]))) is prepared by hydrogenation of (Cp*SiNR)ScCH(SiMe[sub 3])[sub 2] in the presence of trimethylphosphine. The hydride complex is a catalyst precursor for the polymerization of [alpha]-olefins, yielding atactic products of low molecular weight (M[sub n] = 3000-7000). GC/MS analysis of volatile, oligomeric products revealed that all scandium centers are active during the polymerization. Selectivity for head-to-tail insertion is high (> 99%) and for the tetramer, pentamer, and hexamer formed during propene polymerization, the maximum theoretical numbers of head-to-tail stereoisomers are observed by capillary GC. The stoichiometric reaction between 1 and 2 equiv of ethylene produces the unusual ethylene-bridged dimer [(Cp*SiNR)(PMe[sub 3])Sc][sub 2]([mu], [eta][sup 2]-C[sub 2]H[sub 4]) (2) and an equivalent of ethane, whereas the same reaction with propene affords the phosphine-free, alkyl-bridged scandium dimer [(Cp*SiNR)Sc][sub 2]([mu]-CH[sub 2]CH[sub 2]CH[sub 3])[sub 2] (3). The absence of coordinating phosphine allows the latter complex to function as a more active olefin polymerization catalyst precursor. 1 reacts with styrene to form a unique double-insertion product arising from sequential 1,2- and 2,1-styrene insertion. 41 refs., 13 figs., 9 tabs.},
doi = {10.1021/ja00090a011},
url = {https://www.osti.gov/biblio/7069751}, journal = {Journal of the American Chemical Society; (United States)},
issn = {0002-7863},
number = ,
volume = 116:11,
place = {United States},
year = {Wed Jun 01 00:00:00 EDT 1994},
month = {Wed Jun 01 00:00:00 EDT 1994}
}