Catalytic Investigation of ε-caprolactone Polymerization through Schiff Base Titanium (IV) Complexes

Title:Catalytic Investigation of ε-caprolactone Polymerization through Schiff Base Titanium (IV) Complexes

Volume: 2

Author(s): Satyendra N. Shukla*, Pratiksha Gaur, Dimple Deharia, Ripul Mehrotra, Sheela Mathews and Vijay Chakrvarti

Affiliation:

• Coordination Chemistry Research Lab, Department of Chemistry, Govt. Science (Autonomous) College, Jabalpur, 482001, MP, India

Keywords: ε-caprolactone, Catalytic activity, Polymerization, Schiff base, Titanium (VI), ROP.

Abstract:

Background: The ring-opening polymerization (ROP) reaction has provided an efficient and convenient route to prepare polyesters of high molecular weight, low polydispersity index, and high optical purity. The poly( ε-caprolactone) (PCL) and poly(lactide) (PLA) were prepared through ROP reaction of ε-caprolactone and D, L-lactide, respectively. These compounds have a huge industrial demand and become an interest among the scientific community to develop more economically and eco-friendly catalysts for ROP reactions.

Methods: Three Schiff base ligands, 2-((benzo[d]thiazole-2-ylimino)methyl)phenol, L₁; 2-(1-benzo[d]thiazole-2-ylimino)ethyl)phenol, L₂; and 2- ((benzo[d]thiazole-2-ylimino)methyl)-5-methoxyphenol, L₃; were prepared by the reaction of 2-aminobenzothiazole with 2-hydroxybenzaldehyde, 2-hydroxyacetophenone and 2-hydroxy-4-methoxybenzaldehyde in 1:1 molar ratio. In anticipation of interesting stereochemistry, reactivity, and catalytic potential against ε-caprolactone polymerization, three Titanium(IV) complexes (1 – 3) of these Schiff base ligands were synthesized. All the prepared compounds were characterized by elemental analysis, molar conductance, FT-IR, UV-Vis, ¹H-NMR, ¹³C{¹H}-NMR and FAB-Mass spectroscopic technique. Geometry was optimized with the help of DFT.

Results: Complex 3 gives a much higher yield (87.7%) in comparison to 1 and 2. The order of catalytic efficiency for complexes is 3>1>2. With the increase in temperature, the % yield was found to decrease, and results are in support of moderate to good potency of synthesized catalysts.

Conclusion: Complexes were screened for catalytic potency against ε-Caprolactone polymerization reaction. A most plausible mechanism for the polymerization was also proposed.

Cite this article as:

Shukla Satyendra N.*, Gaur Pratiksha, Deharia Dimple, Mehrotra Ripul, Mathews Sheela and Chakrvarti Vijay, Catalytic Investigation of ε-caprolactone Polymerization through Schiff Base Titanium (IV) Complexes, Current Indian Science 2024; 2 : e2210299X302408 . https://dx.doi.org/10.2174/012210299X302408240607073134