Simple Zn(ii) complexes for the production and degradation of polyesters

Abstract

Nine new complexes based on thioether appended iminophenolate (ONS) ligands have been prepared and fully characterized in solution by NMR spectroscopy.

Homoleptic phenoxy-imine pyridine zinc complexes: efficient catalysts for solvent free synthesis and chemical degradation of polyesters

“…In this context, discrete homogeneous metal complexes with defined structures may offer great opportunities but they are still poorly investigated as catalysts. [37][38][39][40][41] Recently, several homoleptic zinc complexes stabilized by monoanionic (NNO) ligands have been reported by Jones as efficient catalysts for the synthesis and alcoholysis of PLA. [42][43][44] For these systems the neutral amine of the ligands seems to have a crucial role in assisting the depolymerization via H bond activation of the alcohol.…”

Well-Defined and Highly Effective Nickel Catalysts Coordinated on Tridentate SNO Schiff-Base Derivatives for Alternating Copolymerization of Epoxides and Anhydrides

“…SNO Schiff-base proligands in the form of 2-hydroxybenzaldehyde derivatives with 2-(methylthio)-ethylamine in refluxing ethanol (L 1 -H to L 9 -H) have been reported. − The method for synthesizing Ni complexes containing tridentate SNO Schiff-base ligands was tested, as presented in Scheme . The reaction of the proligands L 1 -H to L 5 -H [L 1 -H = 2-(((2-(methylthio)­ethyl)­imino)­methyl)­phenol, L 2 -H = 2,4-di- tert -butyl-6-(((2-(methylthio)­ethyl)­imino)­methyl)­phenol, L 3 -H = 2-(((2-(methylthio)­ethyl)­imino)­methyl)-4,6-bis­(2-phenylpropan-2-yl)­phenol, L 4 -H = 4-bromo-2-(((2-(methylthio)­ethyl)­imino)­methyl)­phenol, and L 5 -H = 4-chloro-2-(((2-(methylthio)­ethyl)­imino)­methyl)­phenol] with 1.0 molar equiv Ni­(OAc) 2 ·4H 2 O in refluxing methanol yielded monomeric six-coordinate nickel­(II) complexes 1 – 5 .…”

Mononuclear Zn(ii) compounds supported by iminophenolate proligands binding in the bidentate (N, O) and tridentate (N, O, S) coordination mode: synthesis, characterization and polymerization studies

“…There are very few reports where the heteroatom other than nitrogen (N) and oxygen (O) forms the part of the chelate bonded to the Zn(II) center. [51][52][53] The ring-opening copolymerization (ROCOP) of CO 2 with epoxides to produce aliphatic polycarbonates is an efficient method to utilize CO 2 since epoxides have a high ring-strain which acts as a driving force to overcome the thermodynamic stability of CO 2 . 54 Due to their biodegradability and biocompatibility the aliphatic polycarbonates find extensive application in biomedicine.…”

“…There are very few reports where the heteroatom other than nitrogen (N) and oxygen (O) forms the part of the chelate bonded to the Zn( ii ) center. 51–53…”