Muneer Shaik

Date of Award

January 2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

Guodong D. Du

Abstract

This research aims to explore the potential of zinc amido-oxazolinate complexes as catalysts for ring opening polymerization (ROP) and ring opening copolymerization (ROCOP). ROP is a method for synthesizing polymers by opening cyclic monomers, while ROCOP involves using two different monomers to create a copolymer. The ROP of lactones is a well-established method for the synthesis of polyesters, whereas the ROCOP of epoxides and cyclic anhydrides is a more recent development. Zinc amido-oxazolinate complexes are a promising class of catalysts due to their tunable electronic properties and high reactivity. The catalytic activity of these complexes can be tuned by modifying the structure of the ligands and the reaction conditions, such as temperature, solvent, and concentration. One of the advantages of using zinc amido-oxazolinate complexes as catalysts for ROP and ROCOP is their ability to control the molecular weight and polydispersity of the resulting polymers. This control allows for the production of polymers with specific properties, such as high molecular weight and narrow molecular weight distribution, which are important for various applications. Through the use of a series of highly active chiral and achiral bidentate N-N amido-oxazolinate zinc complexes, we were able to catalyze the ring-opening copolymerization (ROCOP) of epoxides with various anhydrides, resulting in polyesters with tunable glass transition temperatures ranging from 60 °C to 165 °C, and the ring-opening polymerization (ROP) of lactones, yielding cyclic polyesters with high molecular weights. Cyclic statistical, gradient, and diblock copolymers are formed using ROP of ε-CL, δ-VL, and β-BBL by altering the reaction conditions or taking advantage of the different reactivity of the various monomers. 1H-NMR, 13C-NMR, DOSY, ESI mass spectrometry, GPC, TGA, and DSC techniques were used to analyze the structure of cyclic copolymers.

Download

Share

COinS