Thorium 2-pyridylamidinates: Synthesis, structure and catalytic activity towards the cyclo-oligomerization of ε-caprolactone

Elena Rabinovich; Sinai Aharonovich; Mark Botoshansky; Moris S. Eisen

doi:10.1039/c000661k

Thorium 2-pyridylamidinates: Synthesis, structure and catalytic activity towards the cyclo-oligomerization of ε-caprolactone

Elena Rabinovich, Sinai Aharonovich, Mark Botoshansky, Moris S. Eisen

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

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Abstract

Salt metathesis of ThCl₄·3THF with N,N′- bis(trimethylsilyl)-2-pyridyl-lithium-TMEDA (1) yields bis(N,N′- bis(trimethylsilyl)-2-pyridylamidinate) thorium-chloride (μ-Cl) ₂Li(TMEDA) (2) (60% isolated yield) and tris(N,N′- bis(trimethylsilyl)-2-pyridylamidinate) thorium monochloride (3) (10% isolated yield). The latter compound is the first crystallographically characterized tris(amidinate) thorium complex. The bis pyridyl amidinate thorium (2) displays a unique reactivity towards the dual-site cyclo-oligomerization of ε-caprolactone, which produces two fractions of macrocyclic oligo-esters with extremely narrow (1.01-1.06) polydispersity. A mechanism for the dual-site oligomerization reaction is proposed based on kinetic, poisoning, and ¹H NMR studies.

Original language	English
Pages (from-to)	6667-6676
Number of pages	10
Journal	Dalton Transactions
Volume	39
Issue number	29
DOIs	https://doi.org/10.1039/c000661k
State	Published - 2010
Externally published	Yes

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title = "Thorium 2-pyridylamidinates: Synthesis, structure and catalytic activity towards the cyclo-oligomerization of ε-caprolactone",

abstract = "Salt metathesis of ThCl4·3THF with N,N′- bis(trimethylsilyl)-2-pyridyl-lithium-TMEDA (1) yields bis(N,N′- bis(trimethylsilyl)-2-pyridylamidinate) thorium-chloride (μ-Cl) 2Li(TMEDA) (2) (60% isolated yield) and tris(N,N′- bis(trimethylsilyl)-2-pyridylamidinate) thorium monochloride (3) (10% isolated yield). The latter compound is the first crystallographically characterized tris(amidinate) thorium complex. The bis pyridyl amidinate thorium (2) displays a unique reactivity towards the dual-site cyclo-oligomerization of ε-caprolactone, which produces two fractions of macrocyclic oligo-esters with extremely narrow (1.01-1.06) polydispersity. A mechanism for the dual-site oligomerization reaction is proposed based on kinetic, poisoning, and 1H NMR studies.",

author = "Elena Rabinovich and Sinai Aharonovich and Mark Botoshansky and Eisen, {Moris S.}",

year = "2010",

doi = "10.1039/c000661k",

language = "英语",

volume = "39",

pages = "6667--6676",

journal = "Dalton Transactions",

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publisher = "Royal Society of Chemistry",

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TY - JOUR

T1 - Thorium 2-pyridylamidinates

T2 - Synthesis, structure and catalytic activity towards the cyclo-oligomerization of ε-caprolactone

AU - Rabinovich, Elena

AU - Aharonovich, Sinai

AU - Botoshansky, Mark

AU - Eisen, Moris S.

PY - 2010

Y1 - 2010

N2 - Salt metathesis of ThCl4·3THF with N,N′- bis(trimethylsilyl)-2-pyridyl-lithium-TMEDA (1) yields bis(N,N′- bis(trimethylsilyl)-2-pyridylamidinate) thorium-chloride (μ-Cl) 2Li(TMEDA) (2) (60% isolated yield) and tris(N,N′- bis(trimethylsilyl)-2-pyridylamidinate) thorium monochloride (3) (10% isolated yield). The latter compound is the first crystallographically characterized tris(amidinate) thorium complex. The bis pyridyl amidinate thorium (2) displays a unique reactivity towards the dual-site cyclo-oligomerization of ε-caprolactone, which produces two fractions of macrocyclic oligo-esters with extremely narrow (1.01-1.06) polydispersity. A mechanism for the dual-site oligomerization reaction is proposed based on kinetic, poisoning, and 1H NMR studies.

AB - Salt metathesis of ThCl4·3THF with N,N′- bis(trimethylsilyl)-2-pyridyl-lithium-TMEDA (1) yields bis(N,N′- bis(trimethylsilyl)-2-pyridylamidinate) thorium-chloride (μ-Cl) 2Li(TMEDA) (2) (60% isolated yield) and tris(N,N′- bis(trimethylsilyl)-2-pyridylamidinate) thorium monochloride (3) (10% isolated yield). The latter compound is the first crystallographically characterized tris(amidinate) thorium complex. The bis pyridyl amidinate thorium (2) displays a unique reactivity towards the dual-site cyclo-oligomerization of ε-caprolactone, which produces two fractions of macrocyclic oligo-esters with extremely narrow (1.01-1.06) polydispersity. A mechanism for the dual-site oligomerization reaction is proposed based on kinetic, poisoning, and 1H NMR studies.

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U2 - 10.1039/c000661k

DO - 10.1039/c000661k

M3 - 文章

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AN - SCOPUS:77954707287

SN - 1477-9226

VL - 39

SP - 6667

EP - 6676

JO - Dalton Transactions

JF - Dalton Transactions

IS - 29

ER -

Thorium 2-pyridylamidinates: Synthesis, structure and catalytic activity towards the cyclo-oligomerization of ε-caprolactone

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