Synthesis and characterization of Ti-/Zr-diphenylpropanedione complexes and their application in the ring opening polymerization of Ɛ-caprolactone

Abstract

The purpose has been to achieve a controlled ring-opening polymerization of ɛcaprolactone, resulting in polymers with desirable properties such as high molecular weight, low polydispersity index, and highly regio-/stereo regular forms. Therefore, it is important to synthesize single site or reduced number of active site metal alkoxide compounds as catalysts. Ti(IV)/Zr(IV) diphenylpropanedione complexes were synthesized by reactions of titanium or zirconium alkoxides with diphenylpropanedione (dion) ligand. The obtained complexes were characterized by nuclear magnetic resonance ( 1 H-, 13 C-NMR), high resolution mass (HRMS), Fourier transform infrared (FTIR) spectroscopies and elemental analysis. These compounds were tested as catalysts for the ring opening polymerization of Ɛ-caprolactone. The structure of poly-caprolactone (PCL) was analyzed by some spectroscopic techniques (NMR, FTIR) and gel permeation chromatography (GPC). In this work, all Ti-/Zr-complexes were effective over polymerization of Ɛ-caprolactone in solventless environment. Consequently, Ɛ-caprolactone polymers were obtained different average molecular weights between 7000-34000 Da with the PDI values of 1.14-1.60.Cite this: Gökalp Y, Kayan A. Synthesis and characterization of Ti-/Zr-diphenylpropanedione complexes and their application in the ring opening polymerization of Ɛ-caprolactone.

Polycaprolactone Composites/Blends and Their Applications Especially in Water Treatment

“…Following ε-caprolactone monomers bind to the metal center and insert into the metal-alkoxide bond, resulting in PCL formation. Some of the most commonly used catalysts in ROP can be listed as tin octoate [33], metal alkoxides including aluminum [34], tin [35], zirconium [36], or titanium [37], rare earth metal alkoxides and their derivatives containing coordinated Lewis bases (Ln(OR) 3 (L) n ) (L = 2,2 -bipyridyl, n = 2, 1,10-phenanthroline, n = 1, 18-crown-6 ether, n = 1) [38], transition metal(TM)-carboxylates as in zinc (3,5-dimethylpyrazole)carboxylates [39], TM-phenolates like titanium compounds (LTiX 2 ) bearing a sulfide-linked bis(phenol) ligand (L = OSSO type ligand) [40,41], TM-Schiff base complexes such as (LLa(OC 6 H 2 -2,6-t Bu 2 -4-CH 3 )(THF)), (LLaO t Bu(THF)), [LLaO i Pr] 2 , (LLaOBn) 2 , and (LLaOEt) 2 (L = NH(CH 2 CH 2 N=CHC 6 H 2 -3,5-t Bu 2 -2-O) 2 ) [42]. ε-CL was recently initiated by exfoliated oxidized biochar (Eoxbc).…”