Cationic and dicationic zirconocene compounds as initiators of carbocationic isobutene polymerisation

Jorg Sassmannshausen

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We report the polymerisation of isobutene with the intramolecular aryl stabilised zirconocene cations [eta(5)-Cp-(eta(5)-C5H4-CMe2C6H4Me)ZrMe](+) (3), [(eta(5)-C5H4-CMe2C6H4Me)(2)ZrMe](+) (4) and dication [(eta(5)-C5H4-CMe2C6H4Me)(2)Zr](2+) (5) (Cp = C5H5) which were generated in situ by the reaction of the corresponding dimethyl compound with the cation generating agent (CGA) B(C6F5)(3). Whereas the cationic compounds gave polyisobutene in moderate yields, the dicationic compound gave polyisobutene in excellent yields and high molecular weight. Computational studies of the cationic and dicationic compounds were undertaken to ascertain the nature of the cationic initiator. Judging from natural charges and bond critical points, the coordinated monomer is more strongly polarised in the case of the dication 5, compared with the monocation 3. Furthermore, in the case of the cationic compound 3, decomposition into the allylic compound was computed. We found that the activation barrier of this process is 103.3 kJ mol(-1), which is too high for a direct C-H activation by the Zr-Me group.
LanguageEnglish
Pages9026-9032
Number of pages6
JournalDalton Transactions
Issue number41
DOIs
Publication statusPublished - 2009

Fingerprint

Cations
Chemical activation
Polymerization
Monomers
Molecular weight
Decomposition
isobutylene
Zirconocene dichloride

Keywords

  • living isobutylene polymerization
  • density-functional calculations
  • ticl4 reaction order
  • catalyst deactivation
  • manganese(ii) complexes
  • propene polymerization
  • noncoordinating anions
  • hydrocarbon properties
  • metallocene catalysts
  • alkene polymerization

Cite this

@article{b6fcfb5435954d14a2ad88c42a29a989,
title = "Cationic and dicationic zirconocene compounds as initiators of carbocationic isobutene polymerisation",
abstract = "We report the polymerisation of isobutene with the intramolecular aryl stabilised zirconocene cations [eta(5)-Cp-(eta(5)-C5H4-CMe2C6H4Me)ZrMe](+) (3), [(eta(5)-C5H4-CMe2C6H4Me)(2)ZrMe](+) (4) and dication [(eta(5)-C5H4-CMe2C6H4Me)(2)Zr](2+) (5) (Cp = C5H5) which were generated in situ by the reaction of the corresponding dimethyl compound with the cation generating agent (CGA) B(C6F5)(3). Whereas the cationic compounds gave polyisobutene in moderate yields, the dicationic compound gave polyisobutene in excellent yields and high molecular weight. Computational studies of the cationic and dicationic compounds were undertaken to ascertain the nature of the cationic initiator. Judging from natural charges and bond critical points, the coordinated monomer is more strongly polarised in the case of the dication 5, compared with the monocation 3. Furthermore, in the case of the cationic compound 3, decomposition into the allylic compound was computed. We found that the activation barrier of this process is 103.3 kJ mol(-1), which is too high for a direct C-H activation by the Zr-Me group.",
keywords = "living isobutylene polymerization, density-functional calculations, ticl4 reaction order, catalyst deactivation, manganese(ii) complexes, propene polymerization, noncoordinating anions, hydrocarbon properties, metallocene catalysts, alkene polymerization",
author = "Jorg Sassmannshausen",
year = "2009",
doi = "10.1039/b908611k",
language = "English",
pages = "9026--9032",
journal = "Dalton Transactions",
issn = "1477-9226",
number = "41",

}

Cationic and dicationic zirconocene compounds as initiators of carbocationic isobutene polymerisation. / Sassmannshausen, Jorg.

In: Dalton Transactions, No. 41, 2009, p. 9026-9032.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Cationic and dicationic zirconocene compounds as initiators of carbocationic isobutene polymerisation

AU - Sassmannshausen, Jorg

PY - 2009

Y1 - 2009

N2 - We report the polymerisation of isobutene with the intramolecular aryl stabilised zirconocene cations [eta(5)-Cp-(eta(5)-C5H4-CMe2C6H4Me)ZrMe](+) (3), [(eta(5)-C5H4-CMe2C6H4Me)(2)ZrMe](+) (4) and dication [(eta(5)-C5H4-CMe2C6H4Me)(2)Zr](2+) (5) (Cp = C5H5) which were generated in situ by the reaction of the corresponding dimethyl compound with the cation generating agent (CGA) B(C6F5)(3). Whereas the cationic compounds gave polyisobutene in moderate yields, the dicationic compound gave polyisobutene in excellent yields and high molecular weight. Computational studies of the cationic and dicationic compounds were undertaken to ascertain the nature of the cationic initiator. Judging from natural charges and bond critical points, the coordinated monomer is more strongly polarised in the case of the dication 5, compared with the monocation 3. Furthermore, in the case of the cationic compound 3, decomposition into the allylic compound was computed. We found that the activation barrier of this process is 103.3 kJ mol(-1), which is too high for a direct C-H activation by the Zr-Me group.

AB - We report the polymerisation of isobutene with the intramolecular aryl stabilised zirconocene cations [eta(5)-Cp-(eta(5)-C5H4-CMe2C6H4Me)ZrMe](+) (3), [(eta(5)-C5H4-CMe2C6H4Me)(2)ZrMe](+) (4) and dication [(eta(5)-C5H4-CMe2C6H4Me)(2)Zr](2+) (5) (Cp = C5H5) which were generated in situ by the reaction of the corresponding dimethyl compound with the cation generating agent (CGA) B(C6F5)(3). Whereas the cationic compounds gave polyisobutene in moderate yields, the dicationic compound gave polyisobutene in excellent yields and high molecular weight. Computational studies of the cationic and dicationic compounds were undertaken to ascertain the nature of the cationic initiator. Judging from natural charges and bond critical points, the coordinated monomer is more strongly polarised in the case of the dication 5, compared with the monocation 3. Furthermore, in the case of the cationic compound 3, decomposition into the allylic compound was computed. We found that the activation barrier of this process is 103.3 kJ mol(-1), which is too high for a direct C-H activation by the Zr-Me group.

KW - living isobutylene polymerization

KW - density-functional calculations

KW - ticl4 reaction order

KW - catalyst deactivation

KW - manganese(ii) complexes

KW - propene polymerization

KW - noncoordinating anions

KW - hydrocarbon properties

KW - metallocene catalysts

KW - alkene polymerization

UR - http://dx.doi.org/10.1039/b908611k

U2 - 10.1039/b908611k

DO - 10.1039/b908611k

M3 - Article

SP - 9026

EP - 9032

JO - Dalton Transactions

T2 - Dalton Transactions

JF - Dalton Transactions

SN - 1477-9226

IS - 41

ER -