Monitoring structure and valence state of chromium sites during catalyst formation and ethylene oligomerization by in situ EPR spectroscopy

Angelika Brueckner; K. Jabor Jabor; Ann E. C. McConnell; Paul B. Webb

doi:10.1021/om800316m

Monitoring structure and valence state of chromium sites during catalyst formation and ethylene oligomerization by in situ EPR spectroscopy

Angelika Brueckner^*, K. Jabor Jabor, Ann E. C. McConnell, Paul B. Webb

^*Corresponding author for this work

School of Chemistry

Research output: Contribution to journal › Article › peer-review

Abstract

For the first time, a Cr(acac)3/PNP mixture (PNP = Ph2PN(i-Pr)PPh2) and a [(PNP)CrC12(,U-CI)12 complex were monitored by in situ EPR in cyclohexane and toluene, respectively, during oligomerization of ethylene. For Cr(acac)3/PNP, Cr 3 + reduction is faster than low-spin Cr+ formation, suggesting that the major active species is EPR-silent, possibly an antiferromagnetic Cr+ dimer and/or Cr 21 Fast decomposition of [(PNP)CrC12(U-CI)12 to [Cr07 6 -CH3C6H5)21-+- is a probable reason for low activity.

Original language	English
Pages (from-to)	3849-3856
Number of pages	8
Journal	Organometallics
Volume	27
Issue number	15
DOIs	https://doi.org/10.1021/om800316m
Publication status	Published - 11 Aug 2008

Keywords

TETRAMERIZATION
TRIMERIZATION
COMPLEXES
ACTIVATION
PHOSPHINE
OLEFIN
LIGAND

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10.1021/om800316m

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@article{798dadd1f0e84baea60ebe60118c942b,

title = "Monitoring structure and valence state of chromium sites during catalyst formation and ethylene oligomerization by in situ EPR spectroscopy",

abstract = "For the first time, a Cr(acac)3/PNP mixture (PNP = Ph2PN(i-Pr)PPh2) and a [(PNP)CrC12(,U-CI)12 complex were monitored by in situ EPR in cyclohexane and toluene, respectively, during oligomerization of ethylene. For Cr(acac)3/PNP, Cr 3 + reduction is faster than low-spin Cr+ formation, suggesting that the major active species is EPR-silent, possibly an antiferromagnetic Cr+ dimer and/or Cr 21 Fast decomposition of [(PNP)CrC12(U-CI)12 to [Cr07 6 -CH3C6H5)21-+- is a probable reason for low activity.",

keywords = "TETRAMERIZATION, TRIMERIZATION, COMPLEXES, ACTIVATION, PHOSPHINE, OLEFIN, LIGAND",

author = "Angelika Brueckner and Jabor, \{K. Jabor\} and McConnell, \{Ann E. C.\} and Webb, \{Paul B.\}",

year = "2008",

month = aug,

day = "11",

doi = "10.1021/om800316m",

language = "English",

volume = "27",

pages = "3849--3856",

journal = "Organometallics",

issn = "0276-7333",

publisher = "American Chemical Society (ACS)",

number = "15",

}

TY - JOUR

T1 - Monitoring structure and valence state of chromium sites during catalyst formation and ethylene oligomerization by in situ EPR spectroscopy

AU - Brueckner, Angelika

AU - Jabor, K. Jabor

AU - McConnell, Ann E. C.

AU - Webb, Paul B.

PY - 2008/8/11

Y1 - 2008/8/11

N2 - For the first time, a Cr(acac)3/PNP mixture (PNP = Ph2PN(i-Pr)PPh2) and a [(PNP)CrC12(,U-CI)12 complex were monitored by in situ EPR in cyclohexane and toluene, respectively, during oligomerization of ethylene. For Cr(acac)3/PNP, Cr 3 + reduction is faster than low-spin Cr+ formation, suggesting that the major active species is EPR-silent, possibly an antiferromagnetic Cr+ dimer and/or Cr 21 Fast decomposition of [(PNP)CrC12(U-CI)12 to [Cr07 6 -CH3C6H5)21-+- is a probable reason for low activity.

AB - For the first time, a Cr(acac)3/PNP mixture (PNP = Ph2PN(i-Pr)PPh2) and a [(PNP)CrC12(,U-CI)12 complex were monitored by in situ EPR in cyclohexane and toluene, respectively, during oligomerization of ethylene. For Cr(acac)3/PNP, Cr 3 + reduction is faster than low-spin Cr+ formation, suggesting that the major active species is EPR-silent, possibly an antiferromagnetic Cr+ dimer and/or Cr 21 Fast decomposition of [(PNP)CrC12(U-CI)12 to [Cr07 6 -CH3C6H5)21-+- is a probable reason for low activity.

KW - TETRAMERIZATION

KW - TRIMERIZATION

KW - COMPLEXES

KW - ACTIVATION

KW - PHOSPHINE

KW - OLEFIN

KW - LIGAND

UR - https://www.scopus.com/pages/publications/50549102703

U2 - 10.1021/om800316m

DO - 10.1021/om800316m

M3 - Article

SN - 0276-7333

VL - 27

SP - 3849

EP - 3856

JO - Organometallics

JF - Organometallics

IS - 15

ER -

Monitoring structure and valence state of chromium sites during catalyst formation and ethylene oligomerization by in situ EPR spectroscopy

Abstract

Keywords

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