Polymerization of rac-lactide catalyzed by group 4 metal complexes containing chiral N atoms
2012 (English)In: Polymer Bulletin, ISSN 0170-0839, E-ISSN 1436-2449, Vol. 68, no 7, 1789-1799 p.Article in journal (Refereed) Published
The hydroxyl- and phenoxy-bridged dinuclear zirconium and hafnium complexes, 1 and 2, containing a chiral N atom in the N2O2 ligand (H2L = 2-(((2-pyridylmethyl)(2-hydroxyphenyl)amino)methyl)-4,6-di(tert-butyl)ph enol) were used as catalysts for the ring-opening polymerization of rac-lactide. Experiments prove that 1 and 2 are living and controlled catalytic systems with activity up to 3.25 g(pol) mmol(ini) (-1) h(-1). The isotactic-rich polylactides in a narrow polydispersity (M (w)/M (n) = 1.01-1.13) were produced with enantiomeric complexes 1 and 2 (P (m) = 0.65-0.73). The kinetic studies show a first-order dependency in both monomer and initiator. The initiation mechanism is discussed on the basis of the MALDI-TOF MS and H-1 NMR spectra of the rac-LA oligomer prepared by 1.
Place, publisher, year, edition, pages
2012. Vol. 68, no 7, 1789-1799 p.
Hafnium, Isoselectivity, Lactide, Polymerization, Zirconium
IdentifiersURN: urn:nbn:se:kth:diva-93915DOI: 10.1007/s00289-011-0647-0ISI: 000302255300001ScopusID: 2-s2.0-84861460911OAI: oai:DiVA.org:kth-93915DiVA: diva2:525176
FunderKnut and Alice Wallenberg Foundation
QC 201205072012-05-072012-05-032012-05-07Bibliographically approved