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1610019 
Journal Article 
Aluminum, calcium and zinc complexes supported by potentially tridentate iminophenolate ligands: synthesis and use in the ring-opening polymerization of lactide 
Bouyhayi, M; Sarazin, Y; Casagrande, OL, Jr; Carpentier, JF 
2012 
Yes 
Applied Organometallic Chemistry
ISSN: 0268-2605
EISSN: 1099-0739 
26 
12 
681-688 
English 
WOS:000312137900004 
The coordination chemistry of the potentially tridentate
phenoxyethyl- and benzylaminoethyl-iminophenol pro-ligands {ONO}H and {ONN}H on to calcium, zinc
and aluminum centers has been studied. {ONO}Ca(N(SiMe3)2)(THF) (1) was prepared by a one-pot salt
metathesis procedure but the analogous reaction with {ONN}H led to intractable mixtures. Reaction
of {ONO}H and {ONN}H with ZnEt2 (0.5 or 1 equiv.) systematically led to isolation of the
corresponding homoleptic complexes {ONO}2Zn (2) and {ONN}2Zn (3). The dimethylaluminum complexes
{ONO}AlMe2 (4) and {ONN}AlMe2 (5) were readily prepared by treatment of AlMe3 with 1 equiv. of
the corresponding pro-ligands. Compounds 2 and 4 both feature monomeric structures in the solid
state, with chelating iminophenolate ligands and free-hanging phenoxyethyl arms. The amido
complex 1 was shown to be a moderately active initiator for the controlled ring-opening
polymerization (ROP) of racemic lactide at room temperature, yielding polylactides with high
initiation efficiencies, relatively narrow polydispersities and a slight heterotactic bias.
Immortal polymerizations were achieved by combining excess isopropanol to 1, offering up to 50
macromolecules per metal center, with well-controlled molecular features. The dimethylaluminum
compounds 4 and 5 initiated the controlled ROP of lactide in the presence of 1 equiv. of benzyl
alcohol as a co-initiator but required higher temperatures. Copyright (C) 2012 John Wiley & Sons,
Ltd. 
iminophenolate ligands; calcium; zinc; aluminum; ring-opening polymerization; lactide; catalysis