Chinese scholars have made a series of progress in the research of anionic binding catalytic polymerization methods

Figure (A) Active cationic polymerization catalyzed by anion binding; (B) Active anionic polymerization of amino acid NCA monomers catalyzed by anion binding

With the support of the National Natural Science Foundation of China (approval numbers: 91856113, 22001243), the research group of researcher Tao Youhua of Changchun Institute of Applied Chemistry, Chinese Academy of Sciences has made a series of progress
in the research of anionic binding catalytic polymerization methods 。 The research results were "Anion-binding catalysis enables living cationic polymerization" and "Precision synthesis of polypeptidesvia by active anionic polymerization of N-carboxycyclic anhydride monomer.
" living anionic ring-opening polymerization of N-carboxyanhydrides by tri-thiourea catalysts", recently published in Nature Synthesis and J.
Am.
Chem.
Soc.
)
The links to the papers are: https://doi.
org/10.
1038/s44160-022-00142-0 and https://pubs.
acs.
org/doi/10.
1021/jacs.
2c10950
。 The work was also featured in Nature Synthesis' Research Briefing, which is linked to #article-info
.

The polymer synthesis method is the basis of the polymer material industry, providing an indispensable class of materials
in modern civilized society.
Since Staudinger proposed the concept of polymer in the 2020s, polymer chemists have successively developed several polymerization methods
that have been widely used.
For example, in 1935, Carothers of DuPont proposed the method of condensation polymerization and synthesized nylon-66; In 1953, Ziegler and Nata pioneered the coordination polymerization method of olefins, which ushered in the era of
plastic materials.
The establishment of each polymer synthesis method will trigger a research boom among materials scientists and promote the development of
the polymer industry.

Tao Youhua's research group proposed the strategy of "anion-binding catalytic polymerization", which efficiently and specifically identifies monomers and polymerization chain ends through dynamic reversible donor-anion binding, so as to achieve efficient and highly selective regulation of polymerization reactions (Figure).

。 Based on this strategy, the team designed and synthesized a series of new hydrogen bond donors of selenocyclophosphamide, which dynamically and reversibly activate/dormant cationic active species through binding with anions, accurately control the transient equilibrium conversion between dormant covalent precursors and cationic active species, and then realize the active cationic polymerization of bulk electron-rich ene monomers under mild conditions, which solves many limitations such as the unfriendly environment of traditional active cationic polymerization systems (such as extremely low polymerization temperature, strict anhydrous, polymers, metal residues, etc.
).

The team further discovered that anionic binding catalytic polymerization can also achieve the challenging anionic polymerization of the amino acid N-carboxycyclic
anhydride (NCA) monomer.
Using trithiourea with unique "internal enhancement" as a donor catalyst, they stabilized the active carbamic acid anion through anion binding, and successfully developed an active anion polymerization method
for amino acid NCA monomer.

The above research results extend the strategy of anionic binding catalytic polymerization to active cationic polymerization of bulk electron-rich ene monomers and active anionic polymerization of amino acid NCA monomers, and are expected to be applied to the green and efficient synthesis of bulk and fine polymer materials such as butyl rubber and high-performance rocket propellants and the development and research
of sustainable plastics.