A zinc-diphenylphosphinic amide complex as an efficient catalyst for ring-opening (co)polymerization of cyclic esters: synthesis, mechanism, and DFT insights.

Authors

Anjaneyulu Javisetti, Ravi K Kottalanka, Mallemadugula Ravi Teja, Venkatesan Srinivasadesikan

Published in

Organic & biomolecular chemistry. Oct 26, 2026. Epub Oct 26, 2026.

Abstract

Organophosphorus ligands continue to play a pivotal role in coordination chemistry and catalysis, with phosphine oxide-containing frameworks offering enhanced coordination versatility and electronic tunability. In this study, we report the design and synthesis of a new amido-phosphine oxide ligand derived from 1,1-diphenyl-N-(1-phenylethyl)phosphamide (L1) and its corresponding zinc complex (1). Coordination of the ligand to zinc was achieved through two synthetic routes: (i) direct alkylation with diethylzinc and (ii) a salt-metathesis reaction between zinc chloride and the potassium salt of the racemic amido-phosphine oxide ligand, affording a well-defined zinc complex. Spectroscopic investigations such as ¹H, ¹³C, ³¹P NMR and FT-IR studies fully supported the formation of the divalent zinc complex (1). The amido-phosphine oxide-supported zinc complex (1) was evaluated as a single-component catalyst for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) and L-lactide (LLA), both in the presence and absence of benzyl alcohol as an external initiator. Complex 1 exhibited excellent catalytic activity toward the polymerization of ε-CL and LLA, affording the corresponding PCL and PLA polymers with narrow dispersities (Đ) under mild conditions, particularly at low monomer concentrations. A slight broadening of the dispersity was observed at higher monomer concentrations. Efficient copolymerization of ε-CL and LLA was also achieved in the absence of an external alcohol initiator, demonstrating the robustness of the Zn-OPN catalyst (1) and versatility of the ligand framework (L1). These findings highlight the potential of the amido-phosphine oxide-supported zinc complex as an efficient and adaptable catalyst for the synthesis of biodegradable polyesters with low to moderate dispersities.

PMID:
42932174
Bibliographic data and abstract were imported from PubMed on 27 Oct 2026.

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