scholarly journals Alkoxy-Functionalized Schiff-Base Ligation at Aluminum and Zinc: Synthesis, Structures and ROP Capability

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1090
Author(s):  
Xin Zhang ◽  
Kai Chen ◽  
Melissa Chicoma ◽  
Kimberly Goins ◽  
Timothy J. Prior ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Schiff Base ◽  
High Molecular Weight ◽  
Ring Opening ◽  
Good Control ◽  
Zinc Complexes ◽  
Feed Ratio ◽  
Significant Activity ◽  
Tert Butyl ◽  
Structure Determinations

The Schiff-base compounds 2,4-di-tert-butyl-6-(((3,4,5-trimethoxyphenyl)imino)methyl)phenol (L1H), 2,4-di-tert-butyl-6-(((2,4,6-trimethoxyphenyl)imino)methyl)phenol (L2H), 2,4-di-tert-butyl-6-(((2,4-trimethoxyphenyl)imino)methyl)phenol) (L3H) derived from anilines bearing methoxy substituents have been employed in the preparation of alkylaluminum and zinc complexes. Molecular structure determinations reveal mono-chelate aluminum complexes of the type [Al(Ln)(Me)2] (L1, 1; L2, 2; L3, 3), and bis(chelate) complexes for zinc, namely [Zn(Ln)2] (L1, 5; L2, 6; L3, 7). All complexes have significant activity at 50 °C and higher activity at 100 °C for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) with good control over the molar mass distribution (Mw/Mn < 2) and molecular weight. Complex 1 was found to be the most active catalyst, achieving 99% conversion within 18 h at 50 °C and giving polycaprolactone with high molecular weight; results are compared against aniline-derived (i.e., non-methoxy containing) complexes (4 and 8). Aluminum or zinc complexes derived from L1 exhibit higher activity as compared with complexes derived from L2 and L3. Complex 1 was also tested as an initiator for the copolymerization of ε-CL and glycolide (GL). The CL-GL copolymers have various microstructures depending on the feed ratio. The crosslinker 4,4′-bioxepane-7,7′-dione was used in the polymerization with ε-CL using 1, and well-defined cross-linked PCL was afforded of high molecular weight.

Catalytic Ring-Opening Polymerization of Renewable Macrolactones to High Molecular Weight Polyethylene-like Polymers

2011 ◽  
Vol 44 (11) ◽  
pp. 4301-4305 ◽  
Author(s):  
Inge van der Meulen ◽  
Erik Gubbels ◽  
Saskia Huijser ◽  
Rafaël Sablong ◽  
Cor E. Koning ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Ring Opening ◽  
Ring Opening Polymerization

Lipase-catalyzed ring-opening copolymerization of ω-pentadecalactone and δ-valerolactone by reactive extrusion

2020 ◽  
Vol 22 (3) ◽  
pp. 662-668
Author(s):  
Changcun Li ◽  
Shuaijun Pan ◽  
Weijian Xu ◽  
Yanbing Lu ◽  
Peipei Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Ring Opening ◽  
Reactive Extrusion ◽  
Novozyme 435

This work demonstrates the synthesis of poly(ω-pentadecalactone-co-δ-valeroLactone) with high molecular weight (Mn = 71.3 kDa) and low polydispersity (Đ = 1.67) within 6 hours by reactive extrusion (REX) using a lipase catalyst (Novozyme-435).

Improvement in zinc complexes bearing Schiff base in ring-opening polymerization of ε-caprolactone: A five-membered ring system

Polymer ◽  
2019 ◽  
Vol 182 ◽  
pp. 121812 ◽  
Author(s):  
Feng-Jie Lai ◽  
Li-Ling Chiu ◽  
Chieh-Ling Lee ◽  
Wei-Yi Lu ◽  
Yi-Chun Lai ◽  
...  
Keyword(s):  
Schiff Base ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Ring System ◽  
Membered Ring ◽  
Zinc Complexes

Article

1998 ◽  
Vol 76 (4) ◽  
pp. 371-381 ◽  
Author(s):  
Ian Manners
Keyword(s):  
Molecular Weight ◽  
Transition Metal ◽  
High Molecular Weight ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Organometallic Polymer ◽  
Wide Range ◽  
Initial Discovery

Ring-opening polymerization (ROP) of strained ring-tilted metallocenophanes can be achieved thermally, via anionic or cationic initiation, or by the use of transition-metal catalysts and provides access to a wide range of high molecular weight (Mw = 105-106, Mn > 105) poly(metallocenes). These materials possess a variety of interesting properties and many are very easy to prepare. This article provides an overview of our work, giving background to and an account of the initial discovery, and discusses work on the synthesis and properties of new poly(metallocenes) and related materials with particular emphasis on recent research directions.Key words: metallocene, ring-opening polymerization, ferrocenophane, organometallic polymer.

scholarly journals Simple generation of neutral bimetallic aluminium and zinc alkyls Schiff bases bridged by a central resorcinol moiety

2010 ◽  
Vol 8 (6) ◽  
pp. 1305-1310 ◽  
Author(s):  
Elham Aazam ◽  
Martyn Coles
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Schiff Base Ligand ◽  
Ring Opening ◽  
Rotation Axis ◽  
Zinc Complexes ◽  
Ethyl Benzene ◽  
Alkyl Complexes ◽  
Neutral Ligands ◽  
Coordinate Geometry

AbstractAluminium and zinc complexes bearing the N,O-chelating Schiff base ligand 4,6-bis-1-(2-(dimethylamino)ethylimino)ethyl)benzene-1,3-diol, (C6H2(OH)2(NCH2CH2NMe2)2) (1a), have been synthesized. Bimetallic aluminium and zinc alkyl complexes (2a–4a) were prepared by treatment of the hexadentate 1a with the appropriate amount of AlMe3, ZnMe2 and ZnEt2, respectively. 2a has been characterized crystallographically, it lies on a crystallographic two-fold rotation axis and each aluminium centre adopts a five coordinate geometry. Complex 2a was tested as a catalyst in the ring-opening polymerisation of ɛ-caprolactone. We describe here the synthesis of two neutral ligands (1a and (C6H2(OH)2(C6H5NH2) (C=O(CH3)) (1b)) and demonstrate their application in the synthesis of molecular aluminium and zinc derivatives.

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