Synthesis and characterizations of bis(phenoxy)‐amine tin(II) complexes for ring‐opening polymerization of lactide

Autor: Khamphee Phomphrai, Jiraya Kiriratnikom, Jonggol Tantirungrotechai, Siriwan Praban, Sucheewin Chotchatchawankul, Supajittra Yimthachote
Rok vydání: 2019
Předmět:
Zdroj: Journal of Polymer Science Part A: Polymer Chemistry. 57:2104-2112
ISSN: 1099-0518
0887-624X
Popis: A series of tin(II) complexes supported by N₂O₂ bis(phenol)‐amine ligands were prepared from the reactions of the corresponding ligands with Sn[N(SiMe₃)₂]₂ in benzene at room temperature. The ligands were designed to have different substituted group at the ortho‐position on the aryl rings (R = ᵗBu, CH₃) and N‐containing side arm (E = CH₂NEt₂ and pyridine) giving a variation of tin(II) complexes (R = ᵗBu, E = CH₂NEt₂, 2a; R = ᵗBu, E = py, 2b; R = CH₃, E = CH₂NEt₂, 2c; R = CH₃, E = py, 2d). All complexes were characterized by NMR spectroscopy and single‐crystal X‐ray analysis. The single‐crystal X‐ray crystallography revealed that all complexes have a monomeric four‐coordinate tin center with a distorted seesaw structure. All complexes are active for solvent‐free polymerization of l‐lactide at 120 °C giving poly(l‐lactide) with narrow to moderate dispersity (Ð = 1.12–1.56). In the presence of benzyl alcohol during the polymerization, the resulting polymer was found to be linear having benzyl alcohol as the end group while, in the absence of benzyl alcohol, the polymer was cyclic. The large ᵗBu group at the ortho‐position was found to decrease polymerization activity while the more basic CH₂NEt₂ group was found to increase the polymerization activity. The polymerization of rac‐lactide under a similar condition gave PLA having a slight heterotactic bias for all catalysts. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2104–2112
Databáze: OpenAIRE
Externí odkaz: