TY - JOUR
T1 - Incorporating Sodium to Boost the Activity of Aluminium TrenSal Complexes towards rac‐Lactide Polymerisation
AU - Zhou, Yali
AU - Nichol, Gary S.
AU - Garden, Jennifer A.
N1 - Funding Information:
We gratefully acknowledge the University of Edinburgh Principal's Career Development PhD Scholarship for funding. J. A. G. also acknowledges the UKRI Future Leaders Fellowship (Grant MR/T042710/1), British Royal Society (Grant RSG\R1\180101), L'Oréal-UNESCO for Women in Science UK & Ireland Fellowship, L'Oréal-UNESCO International Rising Talents Award and the British Ramsay Memorial Trust for funding. Synchrotron data were collected remotely at beam line I-19 of Diamond Light Source (award CY22240).[34]
Funding Information:
We gratefully acknowledge the University of Edinburgh Principal's Career Development PhD Scholarship for funding. J. A. G. also acknowledges the UKRI Future Leaders Fellowship (Grant MR/T042710/1), British Royal Society (Grant RSG\R1\180101), L'Oréal‐UNESCO for Women in Science UK & Ireland Fellowship, L'Oréal‐UNESCO International Rising Talents Award and the British Ramsay Memorial Trust for funding. Synchrotron data were collected remotely at beam line I‐19 of Diamond Light Source (award CY22240). [34]
Publisher Copyright:
© 2022 The Authors. European Journal of Inorganic Chemistry published by Wiley-VCH GmbH.
PY - 2022/4/14
Y1 - 2022/4/14
N2 - Four novel homo- and heterometallic sodium and/or aluminium complexes based on the TrenSal ligand, [LH3], have been synthesised and fully characterised, including by single-crystal X-ray diffraction experiments. While [LAl] was completely inactive towards rac-lactide ring-opening polymerisation, incorporating sodium to form heterometallic [LNaAlMe] changes the aluminium geometry from octahedral to tetrahedral, leading to good catalytic activity in the presence of co-initiator BnOH (kobs=3.19×10−2 min−1; room temperature, toluene solvent) and good polymerisation control. Under identical conditions, homometallic sodium complexes showed higher activities in rac-lactide polymerisation than [LNaAlMe], with [LNa3] being extremely active (kobs=1.21 min−1) but displaying unusual second-order monomer dependency and poor polymerisation control. 1H NMR spectroscopic studies suggest that polymerisation with [LNaAlMe] or [LH2Na]/BnOH follows an activated monomer mechanism, whereas [LNa3] operates via simultaneous coordination-insertion and activated monomer mechanisms. Overall, heterometallic [LNaAlMe] provides a balance of good activity and control compared to the homometallic analogues.
AB - Four novel homo- and heterometallic sodium and/or aluminium complexes based on the TrenSal ligand, [LH3], have been synthesised and fully characterised, including by single-crystal X-ray diffraction experiments. While [LAl] was completely inactive towards rac-lactide ring-opening polymerisation, incorporating sodium to form heterometallic [LNaAlMe] changes the aluminium geometry from octahedral to tetrahedral, leading to good catalytic activity in the presence of co-initiator BnOH (kobs=3.19×10−2 min−1; room temperature, toluene solvent) and good polymerisation control. Under identical conditions, homometallic sodium complexes showed higher activities in rac-lactide polymerisation than [LNaAlMe], with [LNa3] being extremely active (kobs=1.21 min−1) but displaying unusual second-order monomer dependency and poor polymerisation control. 1H NMR spectroscopic studies suggest that polymerisation with [LNaAlMe] or [LH2Na]/BnOH follows an activated monomer mechanism, whereas [LNa3] operates via simultaneous coordination-insertion and activated monomer mechanisms. Overall, heterometallic [LNaAlMe] provides a balance of good activity and control compared to the homometallic analogues.
U2 - 10.1002/ejic.202200134
DO - 10.1002/ejic.202200134
M3 - Article
JO - European journal of inorganic chemistry
JF - European journal of inorganic chemistry
SN - 1434-1948
ER -