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 journalArticlepeer-review

37 Scopus citations

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 languageEnglish
Pages (from-to)6667-6676
Number of pages10
JournalDalton Transactions
Volume39
Issue number29
DOIs
StatePublished - 2010
Externally publishedYes

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