Synthesis and structural characterization of lithium, sodium and potassium complexes supported by a tridentate amino-bisphenolate ligand

Metal Complexes as Catalysts/Moderators for Polymerization Reactions

“…Numerous alkali metal aryloxide species (ArOM) were shown to efficiently polymerize lactide under mild conditions. [257][258][259][260] The steric and electronic properties of the supported aryloxide ligand play a crucial role in ROP activity and stereoselectivity, with the preferred use of multidentate aryloxide ligands, such as 4.1-4.3 (Figure 4.2), [261][262][263][264][265] to control and limit catalyst aggregation. Remarkably, salts 4.3, in which the Na + or K + metal ion is supported by an ancillary crown ether and a sterically demanding phenoxide, are highly active catalysts for the iso-selective ROP of rac-lactide, producing chain-length-controlled isotactic PLA (complete conversion of 500 equiv LA, 10 min, RT, 10 equiv BnOH, Pm = 0.82).…”

Bulky alkylaminophenol chelates with high potential for functionalization

“…They are vastly applied for coordination of first row transition complexes, serving, for example, as catalysts in oxidation [2e5], polymerization processes [6], or organic carbonate synthesis from CO 2 [7e9]. Their benefits come from the tripod geometry of the alkylamine skeleton that allows for the formation of a chelating structure [10,11]. The amine nitrogen atom opens up the possibility of symmetry control [12].…”