Factors influencing catalytic behavior of titanium complexes bearing bisphenolate ligands toward ring-opening polymerization of L-lactide and ε-caprolactone

Abstract

Abstract.A series of titanium complexes bearing substituted diphenolate ligands (RCH(phenolate) 2 , where R = H, CH 3 ,2, was synthesized and studied as catalysts for the ring opening polymerization of L-lactide and ε-caprolactone. Ligands were designed to probe the role of chelate effect and steric effect in the catalytic performance. From the structure of triphenolate (with one extra coordination site than diphenolate ligand) Ti complex, TriOTiO i Pr 2 , we found no additional chelation to influence the catalytic activity of Ti complexes. It was found that bulky aryl groups in the diphenolate ligands decreased the rate of polymerization most. We conclude that steric effect is the most controlling factor in these polymerization reactions by using Ti complexes bearing diphenolate ligands as catalysts since it is responsible for the exclusion of needed space for incoming monomer by the bulky substituents on the catalyst.

Use of Titanium Complexes Bearing Diphenolate or Calix[n]arene Ligands in α-Olefin Polymerization and the ROP of Cyclic Esters

“…Diphenolate-supported mixed heterobimetallic Ti complexes [27]. Figure 14) [28]. The influence of the nature of the substituents on the ROP of -CL and L-LA was investigated Very recently, Chen et al disclosed the synthesis of a number of dinuclear titanium complexes supported by diphenolate ligands having various substituents on the methyne bridge ( Figure 14) [28].…”

“…Figure 14) [28]. The influence of the nature of the substituents on the ROP of -CL and L-LA was investigated Very recently, Chen et al disclosed the synthesis of a number of dinuclear titanium complexes supported by diphenolate ligands having various substituents on the methyne bridge ( Figure 14) [28]. The influence of the nature of the substituents on the ROP of ε-CL and L-LA was investigated (Table 16).…”

Synthesis, characterization and sustainable drug release activity of drug bridged diblock copolymer

“…Terzopoulu et al [3] reported the ROP of CL using SO as a catalyst and initiator. Similarly, other novel initiators such as benzylalcohol [4,5], gelatin [6], lipase [7], mercaptohexanol [8], diethyleneglycol [9], bisphenolate ligand [10] and mPEG [11] were used for the ROP of CL. Due to the bio-degradability and bio-compatibility of PCL, it is used as a drug carrier material.…”

Low temperature splinting activity and catalytic behavior of nano Ag doped sulphamicacid bridged diblock copolymer

“…Organo aluminium complexes derived from anilines were used for the ROP of CL . In 2018, Jiang et al reported a novel catalyst for the ROP of CL . Galia and co‐workers studied the ROP of CL using wet β‐cyclodextrin as a novel catalyst.…”

“…1 In 2018, Jiang et al reported a novel catalyst for the ROP of CL. 2 Galia and co-workers 3 studied the ROP of CL using wet β-cyclodextrin as a novel catalyst. Similarly, other catalysts such as ammoniumheptamolypdate, 4 cyclic trimeric phosphazene base, 5 phosphoricacid, 6 rare earth Schiff base complex, 7 silica compound, 8 zinc complex, 9 and functionalized aluminum alkoxide 10 were used as a catalyst for the ROP of CL.…”