Related Experiment Video
Updated: Dec 23, 2025

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
Published on: November 21, 2017
Synthesis and characterization of guanidinate tin(ii) complexes for ring-opening polymerization of cyclic esters
Thasanaporn Ungpittagul1, Phonpimon Wongmahasirikun, Khamphee Phomphrai
1Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand. khamphee.p@vistec.ac.th.
Abstract:
Novel homoleptic and heteroleptic (guanidinate)tin(ii) complexes were successfully synthesized and structurally characterized. The first heteroleptic (guanidinato)tin(ii) alkoxide complex was synthesized but found to be unstable leading to the corresponding bis(guanidinate)tin(ii) complex. The catalytic activities of bis(guanidinate)tin(ii) complexes having different substituents at the nitrogen atoms (isopropyl (1), cyclohexyl (2), and p-tolyl (3)) were investigated in the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) and lactide (LA). The lone-pair electrons of the tin(ii) atom were proposed to act as an initiator similar to N-heterocyclic carbenes. Among the synthesized catalysts, complex 1 having less steric hindrance efficiently catalyzed both homo- and copolymerizations of ε-CL and LA giving high molecular weight cyclic polyesters. Transesterification was found to be the major contributor to the cyclization to cyclic polyesters.
Related Concept Videos
Ziegler–Natta Chain-Growth Polymerization: Overview
Base-Catalyzed Ring-Opening of Epoxides
Acid-Catalyzed Ring-Opening of Epoxides
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
Olefin Metathesis Polymerization: Overview
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Alkylation of β-Diester Enolates: Malonic Ester Synthesis

