Zinc Complexes of New Chiral Aminophenolate Ligands: Synthesis, Characterization and Reactivity toward Lactide

Abstract

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Toward the Synthesis of Heteroleptic Zinc ROP Initiators Based on Pyridine-Containing Monoalcohols by Tuning Ligand Substituents

“…7 Though heteroleptic amide zinc complexes are well documented, for example, for amido−oxazolinates, 9 diiminates, 6a bis(imino)diphenylamido ligands, 10 or for the aminoamide ligand, 11 for ON-type ligands, it is often challenging to obtain such types of complexes because of the formation of the homoleptic ones (Figure 2). To the best of our knowledge, existing examples are limited to ones based on salicylaldiminato ligands, 12 isoquinolinyl-naphtholate ligands, 13 (imidazole-[1,5-a]pyrid-3-yl)phenolate ligands, 14 and aminophenols, 15 and the structural characterization of only one compound has been made. 12a Also, it is worth mentioning that the complex, synthesized by the Ma group, where the formal denticity of the ligand is 3 (ONN type) but no coordination between additional nitrogen and zinc is observed in the solid state.…”

Synthesis and Characterization of N,N,O-Tridentate Aminophenolate Zinc Complexes and Their Catalysis in the Ring-Opening Polymerization of Lactides

“…Ring-opening polymerization (ROP) by using metal complexes (Bellemin and Dagorne, 2014; Guillaume et al, 2015; Sarazin and Carpentier, 2015; Huang et al, 2016; Fuoco and Pappalardo, 2017; Redshaw, 2017) as catalysts is a common method for the efficient synthesis of PLA. Because no cytotoxic metal residue is required in PLA for the biomaterials, the use of a non-cytotoxic metal such as zinc (Williams et al, 2003; Romain and Williams, 2014; Yang et al, 2015; Binda et al, 2016; Ebrahimi et al, 2016; Thevenon et al, 2016; Wang et al, 2016) in lactide polymerization has been investigated widely. Ligands are crucial for the catalyst design because their catalytic activity can be increased.…”