Hydrogen Bond Donor Catalyzed Cationic Polymerization of Vinyl Ethers

Abstract

The synthesis of high‐molecular‐weight poly(vinyl ethers) under mild conditions is a significant challenge, since cationic polymerization reactions are highly sensitive to chain‐transfer and termination events. We identified a novel and highly effective hydrogen bond donor (HBD)–organic acid pair that can facilitate controlled cationic polymerization of vinyl ethers under ambient conditions with excellent monomer compatibility. Poly(vinyl ethers) of molar masses exceeding 50 kg mol−1 can be produced within 1 h without elaborate reagent purification. Modification of the HBD structure allowed tuning of the polymerization rate, while DFT calculations helped elucidate crucial intermolecular interactions between the HBD, organic acid, and polymer chain end.

Recent Advances in Living Cationic Polymerization with Emerging Initiation/Controlling Systems

“…However, tight ion complex could regenerate PCCP and terminated polymer chain 17 via intramolecular deprotonation. To prenvent such a side reaction, the same group [ 102 ] further incorporated thiophosphoramide in the presence of PCCP to form a highly effective hydrogen bond donor (HBD)‐organic acid pair, which promotes the LCP to afford PIBVE of M n,GPC = 65.7 kDa and MWD = 1.14 in 1 h at 0 °C.…”

“…The mechanism of PCCP‐assisted LCP Reproduced with permission. [ 48,102 ] Copyright 2020, Wiley‐VCH GmbH.…”

“…As for LCP, polymer chemists have developed a variety of novel initiation systems. For example, external stimuli (e.g., photon and electron) have been exploited to offer temporal control and sequence regulation; [ 48,51,52 ] organic catalysts have been employed to facilitate propagation without metal‐contamination concern; [ 53 ] chiral ligands have revived the usage of Lewis acid/base pairs, and endowed the capability of tuning the tacticity of polymers. [ 54,55 ]…”

Pentacarboxycyclopentadienes in Organic Synthesis

“…Attempts to obtain polymers with a degree of polymerization greater than 100 from monomers 121 using PCCP 1 gave products with lower M n and broadened dispersity Đ. The loss of control over this process was associated with a high level of elimination at the end of the chain and its subsequent transfer through the PCCP anion (Scheme 47) [94].…”

Synthesis and Post‐Polymerization Modification of Defined Functional Poly(vinyl ether)s

“…The conducted polymerizations resulted in polymers with narrow dispersities ( Đ ) ranging from 1.06 to 1.33 with predictable experimental molar masses. Furthermore, they recently expanded their studies, showing that an added hydrogen bond donor molecule stabilizes the formed complex during polymerization and thus enables the synthesis of high molar mass alkyl‐based poly(vinyl ether)s. [ 23 ] However, they did not investigate the polymerizations of vinyl ethers bearing any functional group.…”