NDLI: Aminopiperidine based complexes for lactide polymerisation

Content Provider	World Health Organization (WHO)-Global Index Medicus
Author	Mckeown, P. Davidson, M. G. Thomas, L. H. Jones, M. D. Mahon, M. F. Woodman, T. J. Lowe, J. P.
Description	Author Affiliation: McKeown P ( Doctoral Training Centre in Sustainable Chemical Technologies, University of Bath, Bath BA2 7AY, UK and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK. mj205@bath.ac.uk.); Davidson MG ( Doctoral Training Centre in Sustainable Chemical Technologies, University of Bath, Bath BA2 7AY, UK and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK. mj205@bath.ac.uk.); Lowe JP ( Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK. mj205@bath.ac.uk.); Mahon MF ( Crystallography Centre, Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK. m.f.mahon@bath.ac.uk.); Thomas LH ( Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK. mj205@bath.ac.uk.); Woodman TJ ( Doctoral Training Centre in Sustainable Chemical Technologies, University of Bath, Bath BA2 7AY, UK.); Jones MD ( Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK. mj205@bath.ac.uk.)
Abstract	Herein we report the synthesis and characterisation of a series of salalen and salan ligands derived from 2-(aminomethyl)piperidine. Depending on the choice of starting salicylaldehyde, a bicyclic salan type ligand $(1–3H_{2})$ or imino salalen type ligand (4–6H, $7–9H_{2})$ were prepared. The ligands were successfully complexed to group 4 metals and aluminium; with hafnium and zirconium octahedral complexes, $M(1–3)_{2},$ were realised; whilst with aluminium tetrahedral and trigonal bipyramidal complexes, $Al(1–9)Me_{x}$ (x = 1,2), were isolated. The complexes have been characterised in solution $via^{1}H$ and $^{13}C\{^{1}H\}$ NMR spectroscopy and in the solid state by X-ray crystallography. The group 4 complexes were observed to have a fac–fac arrangement of ligands and there were two isomers present when $3H_{2}$ was ligated. The imino aluminium complexes Al(7–9)Me were isolated as a mixture of diastereoisomers. The resultant complexes were trialed in the ring opening polymerisation of rac-lactide with both heterotactic and isotactic PLA being demonstrated. Tacticity was found to be dependent on the nature of the ligand and metal used; the $M(1–3)_{2}$ complexes were generally found to have a heterotactic preference $(P_{r}$ = 0.67–0.76) and the aluminium polymerisation outcome was dictated more by the steric influence of the ligand, particularly for $Al(4/6)Me_{2}/Al(7/9)Me.$
ISSN	14779226
Issue Number	12
Journal	Dalton Trans.
Volume Number	45
e-ISSN	13645447
Language	English
Publisher	Royal Society of Chemistry
Publisher Date	2016-03-28
Publisher Place	Great Britain (UK)
Access Restriction	Subscribed
Subject Keyword	Chemistry
Content Type	Text
Resource Type	Article
Subject	Inorganic Chemistry

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