Synthesis and characterization of zirconium and hafnium aryloxide compounds and their reactivity towards lactide and ε-caprolactone polymerization

Kun Chun Hsieh, Wen Yi Lee, Li Feng Hsueh, Hon Man Lee, Jui-Hsien Huang

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Abstract

Reactions of 2 equiv. pyrrole with [C4H3N(CH 2NMe2)-2]2M(NEt2)2 in toluene generated tetra-pyrrolyl metal compounds [C4H 3N(CH2NMe2)-2]2M(C4H 4N)2 (3, M = Zr; 4, M = Hf) in moderate yields. Similarly, treatment of metal amides [C4H3N(CH2NMe 2)-2]2M(NEt2)2 with 2,6-dimethylphenol or 2,6-diisopropylphenol in heptane resulted in the elimination of diethylamine along with the formation of the corresponding metal alkoxides [C4H3N(CH2NMe2)-2] 2M(OR)2 (5, M = Zr, R = C6H3-2,6- Me2; 6, M = Hf, R = C6H3-2,6-Me2; 7, M = Zr, R = C6H3-2,6-iPr2; 8, M = Hf, R = C6H3-2,6-iPr2) in moderate yields. All the new compounds were characterized by 1H and 13C NMR spectroscopy and the structures of 3, 4, 6, 7, and 8 have also been determined by X-ray crystallographic studies. The aryloxides and the substituted pyrrolyl ligands in both compounds 5 and 6 show fluxionality as observed by 1H NMR signals. A kinetic study on the ring-opening polymerization of lactide exhibits a first-order reaction of lactide monomer with compound 8. The catalytic properties of all the metal complexes have been studied for the ring-opening polymerization of ε-caprolactone.

Original languageEnglish
Pages (from-to)2306-2312
Number of pages7
JournalEuropean Journal of Inorganic Chemistry
Issue number11
DOIs
Publication statusPublished - 2006 Jun 2

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Hafnium compounds
Metals
Ring opening polymerization
Polymerization
Heptanes
Pyrroles
Coordination Complexes
Toluene
Propofol
Amides
Nuclear magnetic resonance spectroscopy
Monomers
Nuclear magnetic resonance
Ligands
X rays
Kinetics
caprolactone
dilactide

All Science Journal Classification (ASJC) codes

  • Inorganic Chemistry

Cite this

@article{cc40bf68975a479aa093af0ee6df267c,
title = "Synthesis and characterization of zirconium and hafnium aryloxide compounds and their reactivity towards lactide and ε-caprolactone polymerization",
abstract = "Reactions of 2 equiv. pyrrole with [C4H3N(CH 2NMe2)-2]2M(NEt2)2 in toluene generated tetra-pyrrolyl metal compounds [C4H 3N(CH2NMe2)-2]2M(C4H 4N)2 (3, M = Zr; 4, M = Hf) in moderate yields. Similarly, treatment of metal amides [C4H3N(CH2NMe 2)-2]2M(NEt2)2 with 2,6-dimethylphenol or 2,6-diisopropylphenol in heptane resulted in the elimination of diethylamine along with the formation of the corresponding metal alkoxides [C4H3N(CH2NMe2)-2] 2M(OR)2 (5, M = Zr, R = C6H3-2,6- Me2; 6, M = Hf, R = C6H3-2,6-Me2; 7, M = Zr, R = C6H3-2,6-iPr2; 8, M = Hf, R = C6H3-2,6-iPr2) in moderate yields. All the new compounds were characterized by 1H and 13C NMR spectroscopy and the structures of 3, 4, 6, 7, and 8 have also been determined by X-ray crystallographic studies. The aryloxides and the substituted pyrrolyl ligands in both compounds 5 and 6 show fluxionality as observed by 1H NMR signals. A kinetic study on the ring-opening polymerization of lactide exhibits a first-order reaction of lactide monomer with compound 8. The catalytic properties of all the metal complexes have been studied for the ring-opening polymerization of ε-caprolactone.",
author = "Hsieh, {Kun Chun} and Lee, {Wen Yi} and Hsueh, {Li Feng} and Lee, {Hon Man} and Jui-Hsien Huang",
year = "2006",
month = "6",
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language = "English",
pages = "2306--2312",
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T1 - Synthesis and characterization of zirconium and hafnium aryloxide compounds and their reactivity towards lactide and ε-caprolactone polymerization

AU - Hsieh, Kun Chun

AU - Lee, Wen Yi

AU - Hsueh, Li Feng

AU - Lee, Hon Man

AU - Huang, Jui-Hsien

PY - 2006/6/2

Y1 - 2006/6/2

N2 - Reactions of 2 equiv. pyrrole with [C4H3N(CH 2NMe2)-2]2M(NEt2)2 in toluene generated tetra-pyrrolyl metal compounds [C4H 3N(CH2NMe2)-2]2M(C4H 4N)2 (3, M = Zr; 4, M = Hf) in moderate yields. Similarly, treatment of metal amides [C4H3N(CH2NMe 2)-2]2M(NEt2)2 with 2,6-dimethylphenol or 2,6-diisopropylphenol in heptane resulted in the elimination of diethylamine along with the formation of the corresponding metal alkoxides [C4H3N(CH2NMe2)-2] 2M(OR)2 (5, M = Zr, R = C6H3-2,6- Me2; 6, M = Hf, R = C6H3-2,6-Me2; 7, M = Zr, R = C6H3-2,6-iPr2; 8, M = Hf, R = C6H3-2,6-iPr2) in moderate yields. All the new compounds were characterized by 1H and 13C NMR spectroscopy and the structures of 3, 4, 6, 7, and 8 have also been determined by X-ray crystallographic studies. The aryloxides and the substituted pyrrolyl ligands in both compounds 5 and 6 show fluxionality as observed by 1H NMR signals. A kinetic study on the ring-opening polymerization of lactide exhibits a first-order reaction of lactide monomer with compound 8. The catalytic properties of all the metal complexes have been studied for the ring-opening polymerization of ε-caprolactone.

AB - Reactions of 2 equiv. pyrrole with [C4H3N(CH 2NMe2)-2]2M(NEt2)2 in toluene generated tetra-pyrrolyl metal compounds [C4H 3N(CH2NMe2)-2]2M(C4H 4N)2 (3, M = Zr; 4, M = Hf) in moderate yields. Similarly, treatment of metal amides [C4H3N(CH2NMe 2)-2]2M(NEt2)2 with 2,6-dimethylphenol or 2,6-diisopropylphenol in heptane resulted in the elimination of diethylamine along with the formation of the corresponding metal alkoxides [C4H3N(CH2NMe2)-2] 2M(OR)2 (5, M = Zr, R = C6H3-2,6- Me2; 6, M = Hf, R = C6H3-2,6-Me2; 7, M = Zr, R = C6H3-2,6-iPr2; 8, M = Hf, R = C6H3-2,6-iPr2) in moderate yields. All the new compounds were characterized by 1H and 13C NMR spectroscopy and the structures of 3, 4, 6, 7, and 8 have also been determined by X-ray crystallographic studies. The aryloxides and the substituted pyrrolyl ligands in both compounds 5 and 6 show fluxionality as observed by 1H NMR signals. A kinetic study on the ring-opening polymerization of lactide exhibits a first-order reaction of lactide monomer with compound 8. The catalytic properties of all the metal complexes have been studied for the ring-opening polymerization of ε-caprolactone.

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