Journal ArticleDOI
Living ring-opening polymerization of ε-caprolactone catalyzed by β-quinolyl-enamino aluminium complexes: ligand electronic effects
Peng Wang,Jianbin Chao,Xia Chen +2 more
TLDR
The polymerization results showed that 1-5 in the presence of BnOH proceeded efficiently and their catalytic behaviors toward the ROP of ε-CL were significantly affected by the substituents of the aryl ring (Ar) on the end of the enamino framework, where the placement of electron-withdrawing substituent caused higher catalytic activity.Abstract:
A series of β-quinolyl-enamino aluminium complexes [AlLMe2] 1-7 {L = [(2-C9H6N)-CH[double bond, length as m-dash]C(4-MeC6H4)-N(Ar)-], Ar = C6H5 (1), 4-FC6H4 (2), 3,4,5-F3C6H2 (3), C6F5 (4), 5-tBuC6H4 (5), 2,6-Me2C6H3 (6), and 2,6-iPr2C6H3 (7)} were synthesized by the reaction of AlMe3 with the corresponding β-quinolyl-enamine ligands All the complexes were characterized by 1H and 13C NMR spectroscopy and elemental analysis The molecular structures of complexes 1-3 and 7 were confirmed by single-crystal X-ray diffraction, which revealed that all the Al atoms adopt a distorted tetrahedral geometry These Al complexes were tested as the initiators for the ring-opening polymerization (ROP) of e-caprolactone (e-CL) The polymerization results showed that 1-5 in the presence of BnOH proceeded efficiently and their catalytic behaviors toward the ROP of e-CL were significantly affected by the substituents of the aryl ring (Ar) on the end of the enamino framework, where the placement of electron-withdrawing substituents caused higher catalytic activity However 6 and 7 displayed poor activity under the same conditions, suggesting that ortho-substituents on the Ar moieties hamper the coordination-insertion of the e-CL monomer The ROP of e-CL by efficient binary catalytic systems proceeded in a living manner evidenced by the narrow PDIs and the linear nature of Mnversus conversion plots and monomer/catalyst ratiosread more
Citations
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Journal ArticleDOI
Recent progress in the application of group 1, 2 & 13 metal complexes as catalysts for the ring opening polymerization of cyclic esters
Jiahao Gao,Jiahao Gao,Dongzhi Zhu,Dongzhi Zhu,Wenjuan Zhang,Gregory A. Solan,Gregory A. Solan,Yanping Ma,Wen-Hua Sun +8 more
TL;DR: In this paper, a review of the use of well-defined metal complexes based on group 1, 2 and 13 metals to mediate the formation of aliphatic polyesters with a focus on the role played by the auxiliary ligand on influencing catalytic efficiency, controllability, molecular weight as well as stereoselectivity.
Journal ArticleDOI
Alternating Copolymerization of Epoxides and Anhydrides Catalyzed by Aluminum Complexes
Marc Martínez de Sarasa Buchaca,Felipe de la Cruz-Martínez,Javier Martínez,Carlos Alonso-Moreno,Juan Fernández-Baeza,Juan Tejeda,Enrique Niza,José A. Castro-Osma,Antonio Otero,Agustín Lara-Sánchez +9 more
TL;DR: The optimization of an organoaluminum catalytic system for the copolymerization of epoxides and anhydrides is presented and a new copolymers, poly(limonene succinate), is reported.
Journal ArticleDOI
Four- and five-coordinate aluminum complexes supported by N,O-bidentate β-pyrazylenolate ligands: synthesis, structure and application in ROP of ε-caprolactone and lactide
TL;DR: Generally, a β-pyrazyl enolate system exhibited significantly higher catalytic activity for the ROP of ε-CL and rac-LA than the analogous β-quinolyl enolate systems reported recently.
Journal ArticleDOI
Multinuclear metal catalysts in ring-opening polymerization of ε‑caprolactone and lactide: Cooperative and electronic effects between metal centers
TL;DR: In this paper , a review focused on recent reports of multinuclear metal catalysts in ring-opening polymerization (ROP) of cyclic esters, and the strategies and the attention for designing catalysts were also provided.
Journal ArticleDOI
Ring-Opening Polymerization of ε-Caprolactone by Using Aluminum Complexes Bearing Aryl Thioether Phenolates: Labile Thioether Chelation.
Someswara Rao Kosuru,Yu-Lun Chang,Po-Yu Chen,Wei-Chie Lee,Yi-Chun Lai,Shangwu Ding,Hsuan-Ying Chen,Hsing-Yin Chen,Yung Chi Chang +8 more
TL;DR: It is determined that the thioether group is a suitable chelating group for Al catalysts in CL polymerization due to its labile nature.
References
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TL;DR: New features added to the refinement program SHELXL since 2008 are described and explained.
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The path forward for biofuels and biomaterials
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