Dialkylaluminium 2-imidazolylphenolates: Synthesis, characterization and ring-opening polymerization behavior towards lactides

Zhang, Wenjuan; Wang, Youhong; Wang, Lin; Redshaw, Carl; Sun, Wen-Hua

Abstract

The stoichiometric reaction of the 2-imidazolylphenols (L1–L9) with the trialkylaluminium reagents AlR₃ (R = Me, Et and iBu), afforded the corresponding dialkylaluminium 2-imidazolylphenolate complexes [R₂Al(L1–L9)] (C1–C11), which were characterized by ¹H/¹³C NMR spectroscopy and by elemental analysis. The molecular structures of the representative complexes C1, C2, C4, C6 and C11 were determined by single-crystal X-Ray diffraction, and revealed a distorted tetrahedral geometry at aluminum. These dialkylaluminium 2-imidazolylphenolates (C1–C11) could efficiently catalyze the ring-opening polymerization of lactides to afford high molecular weight polylactide, both in the presence and absence of BnOH, and as such represent rare examples of the use of bi-dentate ligation at aluminum in such lactide polymerization systems. On the basis of the polymerization results for l-lactide, d-lactide and rac-lactide, the nature of the ligands and the aluminum bound alkyls were found to significantly affect the catalytic activity as well as the properties of the resultant polylactides.

Citation

Zhang, W., Wang, Y., Wang, L., Redshaw, C., & Sun, W.-H. (2014). Dialkylaluminium 2-imidazolylphenolates: Synthesis, characterization and ring-opening polymerization behavior towards lactides. Journal of organometallic chemistry, 750(January), 65-73. https://doi.org/10.1016/j.jorganchem.2013.11.002

• Journal Article Type: Article
• Acceptance Date: Nov 4, 2013
• Online Publication Date: Nov 12, 2013
• Publication Date: 2014-02
• Deposit Date: Jun 10, 2015
• Publicly Available Date: Jun 10, 2015
• Journal: Journal of organometallic chemistry
• Print ISSN: 0022-328X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 750
• Issue: January
• Pages: 65-73
• DOI: https://doi.org/10.1016/j.jorganchem.2013.11.002
• Keywords: Ring-opening polymerization; Polylactide; Aluminum 2-imidazolylphenolate
• Public URL: https://hull-repository.worktribe.com/output/375063
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0022328X13007997
• Additional Information: Author's accepted manuscript of article published in: Journal of organometallic chemistry, 2014, v.750, January.
• Contract Date: Jun 10, 2015