Ligand-controlled tacticity.
Transition-metal organometallics and simple metal salts as ROP catalysts, resolving the relationship between the pendant ancillary ligand on the metal center and the polymerization behavior.
Ring-Opening Polymerization
ROP of lactides and cyclic esters.
Ring-opening polymerization is the most direct route from a cyclic monomer to a biodegradable polyester. The chemistry that decides whether it works — and what the resulting polymer is like — sits on the metal center.
What ROP does
In ring-opening polymerization the strain of a cyclic ester — lactide, ε-caprolactone, glycolide — is relieved as the ring opens and adds to a growing chain. The result is a polyester whose ester backbone can be hydrolysed, which is what makes materials such as poly(lactide) biodegradable where polyolefins are not.
The catalyst does more than start the reaction. It governs the rate, the molecular weight distribution, and — critically for material properties — the tacticity of the resulting polymer.
Our contribution
Metal-free initiators.
Phosphorus(V) compounds as metal-free ROP catalysts for cyclic esters and lactide, removing metal residues from polyesters destined for biomedical use.
Chiral systems.
Proline- and TADDOL-derived ligands on Zn(II), Al(III) and Group 4 centers for stereocontrol in the ROP of rac-lactide.
Wealth from waste.
L/D-lactide prepared from bio-derived lactic acid recovered from food waste, feeding the same ROP chemistry from a waste stream.
This work is supported by dedicated funding, including an Anusandhan National Research Foundation program on Harnessing Privileged Chiral Ligands for High-Performance Sustainable Polymers.
Selected publications
ROP in our published work.
14 of 124 papers touching ring-opening polymerization, lactides and cyclic esters.
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123
Chiral Proline-derived Zn(II) Complexes as Catalysts for Ring-Opening Polymerization and Ring-Opening Copolymerization Reactions
Polym. Chem. 2026, 17, 758-769.
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119
Highly Isoselective Polymerization of rac‐Lactide by Zinc Complexes of Sequential Tetradentate {ONNN}‐Ligands
ChemSusChem, 2025, e202500402.
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117
An understanding of PLA synthesis using metal catalysts
Polymers for Advanced Technology, Springer Proceedings in Materials 1, 2024. doi:10.1007/978-981-97-7209-4_14
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115
Phenoxy-imine supported hexacoordinate tetravalent titanium compounds: Synthesis, characterization and catalytic applications for ROP and ROCOP reactions
Eur. Polym. J. 2024, 216, 113281.
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109
Living and immortal ring-opening polymerization of cyclic esters
Adv. Mater. Lett. 2023, 23021717-23021737.
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103
Determination of polylactide microstructure by homonuclear decoupled 1H NMR spectroscopy
Chem. Rec. 2021, 21, 1968-1984.
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102
Homoleptic titanium and zirconium complexes exhibiting unusual Oiminol–metal coordination: application in stereoselective ring-opening polymerization of lactide
Polym. Chem. 2021, 12, 3953-3967.
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101
Benzoxazole phenoxide ligand supported group IV catalysts and their application for the ring-opening polymerization of rac-lactide and ε-caprolactone
Polym Adv Technol. 2021, 32, 3392-3401.
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100
Macrocycles in dual role: ancillary ligands in metal complexes and organocatalysts for the ring‑opening polymerization of lactide
J. Incl. Phenom. Macrocycl. Chem. 2021, 100, 1-36.
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99
Co2O3 and MnO2 as inexpensive catalysts for the ring‑opening polymerization of cyclic esters
J. Polym. Res. 2021, 28, 52-60.
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89
Group 4 metal complexes containing the salalen ligands: Synthesis, structural characterization and studies on the ROP of cyclic esters
J. Organomet Chem. 2018, 871, 111-121.
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88
Palladium complexes containing imino phenoxide ligands: synthesis, luminescence, and their use as catalysts for the ring-opening polymerization of rac-lactide
Monatsh Chem 2018, 149, 783-790.
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87
Nb and Ta benzotriazole or benzoxazole phenoxide complexes as catalysts for the ring-opening polymerization of glycidol to synthesize hyperbranched polyglycerols
Dalton Trans. 2017, 46, 16640-16654.
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86
Homoleptic Zr and Hf Complexes of Imino/Bis(imino) phenoxide Scaffolds: Synthesis, Structural Characterization and Their Catalytic Activity in the ROP of Cyclic Esters
ChemistrySelect 2017, 2, 8408-8417.
Work on ROP with us.
Doctoral and postdoctoral projects on ligand design, stereocontrol and metal-free initiators are ongoing.