کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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67211 | 48471 | 2009 | 6 صفحه PDF | دانلود رایگان |
The mechanism of ɛ-caprolactone (CL) insertion into a Y–OCH3 bond was investigated using density functional theory (DFT) calculations. The optimized geometries and corresponding Gibbs-free energies of the intermediates were obtained, which confirmed a four-step coordination-insertion mechanism. The coordination of CL onto yttrium center led to a nucleophilic addition of the carbonyl group of CL, followed by an intramolecular alkoxide ligand exchange. A monomer insertion was completed by the CL ring opening via acyl–oxygen bond cleavage. The formation of the five-coordinated yttrium intermediate, 3, was found to be the rate-determining step. This study could be applicable to ring-opening polymerisation (ROP) of CL initiated by lanthanide metal complexes.
A four-step coordination-insertion mechanism of ɛ-caprolactone (CL) insertion into a Y–OCH3 bond was investigated. The coordination of CL onto yttrium center led to a nucleophilic addition, followed by an intramolecular alkoxide ligand exchange. A monomer insertion was completed by the CL ring opening via acyl–oxygen bond cleavage. The formation of the five-coordinated yttrium intermediate was the rate-determining step. Figure optionsDownload as PowerPoint slide
Journal: Journal of Molecular Catalysis A: Chemical - Volume 300, Issues 1–2, 2 March 2009, Pages 59–64