Silver N-heterocyclic carbene complexes as initiators for bulk ring-opening polymerization (ROP) of l-lactides

Manoja K. Samantaray, Vimal Katiyar, Keliang Pang, Hemant Nanavati, Prasenjit Ghosh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

85 Scopus citations

Abstract

Synthetic, structural and catalysis studies of two silver complexes namely, {[1-(2,4,6-trimethylphenyl)-3-(N-phenylacetamido)imidazol-2-ylidene]2Ag}+Cl- 1b, supported over an amido-functionalized N-heterocyclic carbene ligand, and [1-(i-propyl)-3-(benzyl)imidazol-2-ylidene]AgCl 2b, supported over a non-functionalized N-heterocyclic carbene ligand, are reported. Specifically, 1b, a cationic complex bearing 2:1 NHC ligand to metal ratio, was obtained from the reaction of 1-(2,4,6-trimethylphenyl)-3-(N-phenylacetamido)imidazolium chloride 1a with Ag2O in 52% yield. The corresponding 1a was synthesized by the alkylation reaction of 1-(2,4,6-trimethylphenylimidazole) with N-phenyl chloroacetamide in 73% yield. The other silver complex 2b, a neutral complex bearing 1:1 NHC ligand to metal ratio, was obtained from the reaction of 1-(i-propyl)-3-(benzyl)imidazolium chloride 2a with Ag2O in 42% yield. The 2a was synthesized by the alkylation reaction of 1-(i-propylimidazole) with benzyl chloride in 45% yield. The molecular structures of the imidazolium chloride, 1a, and the silver complexes, 1b and 2b, have been determined by X-ray diffraction studies. The silver complexes, 1b and 2b, successfully catalyze bulk ring-opening polymerization (ROP) of l-lactides at elevated temperatures under solvent-free melt conditions producing moderate to low molecular weight polylactide polymers having narrow molecular weight distributions.

Original languageEnglish (US)
Pages (from-to)1672-1682
Number of pages11
JournalJournal of Organometallic Chemistry
Volume692
Issue number8
DOIs
StatePublished - Mar 15 2007

Keywords

  • Carbenes
  • Functionalized NHC
  • Organometallic complex
  • Silver-NHC complex

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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