Next Article in Journal
Synthesis of New C- and N-β-d-Glucopyranosyl Derivatives of Imidazole, 1,2,3-Triazole and Tetrazole, and Their Evaluation as Inhibitors of Glycogen Phosphorylase
Next Article in Special Issue
Zn(OAc)2-Catalyzing Ring-Opening Polymerization of N-Carboxyanhydrides for the Synthesis of Well-Defined Polypeptides
Previous Article in Journal
Moringa oleifera Leaf Extracts as Multifunctional Ingredients for “Natural and Organic” Sunscreens and Photoprotective Preparations
Previous Article in Special Issue
Tandem Lewis Pair Polymerization and Organocatalytic Ring-Opening Polymerization for Synthesizing Block and Brush Copolymers
Open AccessArticle

Silyl Ketene Acetals/B(C6F5)3 Lewis Pair-Catalyzed Living Group Transfer Polymerization of Renewable Cyclic Acrylic Monomers

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
*
Authors to whom correspondence should be addressed.
Molecules 2018, 23(3), 665; https://doi.org/10.3390/molecules23030665
Received: 30 January 2018 / Revised: 11 March 2018 / Accepted: 14 March 2018 / Published: 15 March 2018
This work reveals the silyl ketene acetal (SKA)/B(C6F5)3 Lewis pair-catalyzed room-temperature group transfer polymerization (GTP) of polar acrylic monomers, including methyl linear methacrylate (MMA), and the biorenewable cyclic monomers γ-methyl-α-methylene-γ-butyrolactone (MMBL) and α-methylene-γ-butyrolactone (MBL) as well. The in situ NMR monitored reaction of SKA with B(C6F5)3 indicated the formation of Frustrated Lewis Pairs (FLPs), although it is sluggish for MMA polymerization, such a FLP system exhibits highly activity and living GTP of MMBL and MBL. Detailed investigations, including the characterization of key reaction intermediates, polymerization kinetics and polymer structures have led to a polymerization mechanism, in which the polymerization is initiated with an intermolecular Michael addition of the ester enolate group of SKA to the vinyl group of B(C6F5)3-activated monomer, while the silyl group is transferred to the carbonyl group of the B(C6F5)3-activated monomer to generate the single-monomer-addition species or the active propagating species; the coordinated B(C6F5)3 is released to the incoming monomer, followed by repeated intermolecular Michael additions in the subsequent propagation cycle. Such neutral SKA analogues are the real active species for the polymerization and are retained in the whole process as confirmed by experimental data and the chain-end analysis by matrix-assisted laser desorption/ionization time of flight mass spectroscopy (MALDI-TOF MS). Moreover, using this method, we have successfully synthesized well-defined PMMBL-b-PMBL, PMMBL-b-PMBL-b-PMMBL and random copolymers with the predicated molecular weights (Mn) and narrow molecular weight distribution (MWD). View Full-Text
Keywords: Frustrated Lewis Pair; group transfer polymerization; silyl ketene acetal; B(C6F5)3 Frustrated Lewis Pair; group transfer polymerization; silyl ketene acetal; B(C6F5)3
Show Figures

Graphical abstract

MDPI and ACS Style

Hu, L.; Zhao, W.; He, J.; Zhang, Y. Silyl Ketene Acetals/B(C6F5)3 Lewis Pair-Catalyzed Living Group Transfer Polymerization of Renewable Cyclic Acrylic Monomers. Molecules 2018, 23, 665.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop