Uranium-mediated ring-opening polymerization of ε-caprolactone: A comparative study

Isabell S.R. Karmel; Maxim Khononov; Matthias Tamm; Moris S. Eisen

doi:10.1039/c5cy01162k

Uranium-mediated ring-opening polymerization of ε-caprolactone: A comparative study

Isabell S.R. Karmel, Maxim Khononov, Matthias Tamm^*, Moris S. Eisen

^*Corresponding author for this work

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

31 Scopus citations

Abstract

The ring-opening polymerization (ROP) of the cyclic ester ε-caprolactone was studied using the uranium(iv) complexes [(Im^DippN)₂U(NMeEt)₂] (3), [(C₅Me₅)₂U(NMe₂)₂] (4) and [(C₅Me₅)₂U(NCMePh)₂] (5) as initiators. While the bis(imidazolin-2-iminato) complex 3 displayed a surprisingly high catalytic activity of 1.2 × 10⁷ g (PCL) mol^-1 h^-1 at room temperature, compounds 4 and 5 exhibited lower catalytic activities even at 90°C. The activity of the uranium complex 3 was further compared to the imidazolin-2-iminato uranium(iv) complexes [(Im^tBuN)₄U] (1) and [(Im^MesN)₃U(NMeEt)] (2), which display catalytic activities of 7.9 × 10³ g (PCL) mol^-1 h^-1, and 5.3 × 10³ g (PCL) mol^-1 h^-1, respectively at an elevated temperature of 90°C. In order to shed light on the operative mechanisms, kinetic studies were carried out with complexes 3-5.

Original language	English
Pages (from-to)	5110-5119
Number of pages	10
Journal	Catalysis Science and Technology
Volume	5
Issue number	12
DOIs	https://doi.org/10.1039/c5cy01162k
State	Published - 3 Sep 2015
Externally published	Yes

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title = "Uranium-mediated ring-opening polymerization of ε-caprolactone: A comparative study",

abstract = "The ring-opening polymerization (ROP) of the cyclic ester ε-caprolactone was studied using the uranium(iv) complexes [(ImDippN)2U(NMeEt)2] (3), [(C5Me5)2U(NMe2)2] (4) and [(C5Me5)2U(NCMePh)2] (5) as initiators. While the bis(imidazolin-2-iminato) complex 3 displayed a surprisingly high catalytic activity of 1.2 × 107 g (PCL) mol-1 h-1 at room temperature, compounds 4 and 5 exhibited lower catalytic activities even at 90°C. The activity of the uranium complex 3 was further compared to the imidazolin-2-iminato uranium(iv) complexes [(ImtBuN)4U] (1) and [(ImMesN)3U(NMeEt)] (2), which display catalytic activities of 7.9 × 103 g (PCL) mol-1 h-1, and 5.3 × 103 g (PCL) mol-1 h-1, respectively at an elevated temperature of 90°C. In order to shed light on the operative mechanisms, kinetic studies were carried out with complexes 3-5.",

author = "Karmel, {Isabell S.R.} and Maxim Khononov and Matthias Tamm and Eisen, {Moris S.}",

note = "Publisher Copyright: {\textcopyright} The Royal Society of Chemistry.",

year = "2015",

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doi = "10.1039/c5cy01162k",

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T1 - Uranium-mediated ring-opening polymerization of ε-caprolactone

T2 - A comparative study

AU - Karmel, Isabell S.R.

AU - Khononov, Maxim

AU - Tamm, Matthias

AU - Eisen, Moris S.

PY - 2015/9/3

Y1 - 2015/9/3

N2 - The ring-opening polymerization (ROP) of the cyclic ester ε-caprolactone was studied using the uranium(iv) complexes [(ImDippN)2U(NMeEt)2] (3), [(C5Me5)2U(NMe2)2] (4) and [(C5Me5)2U(NCMePh)2] (5) as initiators. While the bis(imidazolin-2-iminato) complex 3 displayed a surprisingly high catalytic activity of 1.2 × 107 g (PCL) mol-1 h-1 at room temperature, compounds 4 and 5 exhibited lower catalytic activities even at 90°C. The activity of the uranium complex 3 was further compared to the imidazolin-2-iminato uranium(iv) complexes [(ImtBuN)4U] (1) and [(ImMesN)3U(NMeEt)] (2), which display catalytic activities of 7.9 × 103 g (PCL) mol-1 h-1, and 5.3 × 103 g (PCL) mol-1 h-1, respectively at an elevated temperature of 90°C. In order to shed light on the operative mechanisms, kinetic studies were carried out with complexes 3-5.

AB - The ring-opening polymerization (ROP) of the cyclic ester ε-caprolactone was studied using the uranium(iv) complexes [(ImDippN)2U(NMeEt)2] (3), [(C5Me5)2U(NMe2)2] (4) and [(C5Me5)2U(NCMePh)2] (5) as initiators. While the bis(imidazolin-2-iminato) complex 3 displayed a surprisingly high catalytic activity of 1.2 × 107 g (PCL) mol-1 h-1 at room temperature, compounds 4 and 5 exhibited lower catalytic activities even at 90°C. The activity of the uranium complex 3 was further compared to the imidazolin-2-iminato uranium(iv) complexes [(ImtBuN)4U] (1) and [(ImMesN)3U(NMeEt)] (2), which display catalytic activities of 7.9 × 103 g (PCL) mol-1 h-1, and 5.3 × 103 g (PCL) mol-1 h-1, respectively at an elevated temperature of 90°C. In order to shed light on the operative mechanisms, kinetic studies were carried out with complexes 3-5.

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DO - 10.1039/c5cy01162k

M3 - 文章

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JO - Catalysis Science and Technology

JF - Catalysis Science and Technology

IS - 12

ER -

Uranium-mediated ring-opening polymerization of ε-caprolactone: A comparative study

Abstract

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