Jump to main content
Jump to site search

Issue 46, 2015
Previous Article Next Article

Ring-opening polymerization of rac-lactide mediated by tetrametallic lithium and sodium diamino-bis(phenolate) complexes

Author affiliations

Abstract

Lithium and sodium compounds supported by tetradentate amino-bis(phenolato) ligands, [Li2(N2O2BuBuPip)] (1), [Na2(N2O2BuBuPip)] (2) (where [N2O2BuBuPip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4,6-tert-butylphenol), and [Li2(N2O2BuMePip)] (3), [Na2(N2O2BuMePip)] (4) (where [N2O2BuMePip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4-methyl-6-tert-butylphenol) were synthesized and characterized by NMR spectroscopy and MALDI-TOF mass spectrometry. Variable temperature NMR experiments were performed to understand solution-phase dynamics. The solid-state structures of 1 and 4 were determined by X-ray diffraction and reveal tetrametallic species. PGSE NMR spectroscopic data suggests that 1 maintains its aggregated structure in CD2Cl2. The complexes exhibit good activity for controlled ring-opening polymerization of rac-lactide (LA) both solvent free and in solution to yield PLA with low dispersities. Stoichiometric reactions suggest that the formation of PLA may proceed by the typical coordination–insertion mechanism. For example, 7Li NMR experiments show growth of a new resonance when 1 is mixed with 1 equiv. LA and 1H NMR data suggests formation of a Li-alkoxide species upon reaction of 1 with BnOH.

Graphical abstract: Ring-opening polymerization of rac-lactide mediated by tetrametallic lithium and sodium diamino-bis(phenolate) complexes

Back to tab navigation

Supplementary files

Publication details

The article was received on 12 Aug 2015, accepted on 26 Oct 2015 and first published on 05 Nov 2015


Article type: Paper
DOI: 10.1039/C5DT03119B
Citation: Dalton Trans., 2015,44, 20216-20231
  • Open access: Creative Commons BY license
  •   Request permissions

    Ring-opening polymerization of rac-lactide mediated by tetrametallic lithium and sodium diamino-bis(phenolate) complexes

    D. Alhashmialameer, N. Ikpo, J. Collins, L. N. Dawe, K. Hattenhauer and F. M. Kerton, Dalton Trans., 2015, 44, 20216
    DOI: 10.1039/C5DT03119B

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements