Living Anionic Copolymerization of 1-(Alkylsulfonyl)aziridines to Form Poly(sulfonylaziridine) and Linear Poly(ethylenimine)

Abstract

The anionic ring-opening copolymerization of 1-(methylsulfonyl)aziridine (MsAz) and 1-(sec-butylsulfonyl)aziridine ( s BsAz) produces a soluble random copolymer P(MsAz-r-s BsAz), which can subsequently be converted to linear poly(ethylenimine) (lPEI). The copolymerization of MsAz and s BsAz is living and allows for the synthesis of copolymers with low molecular weight distributions. Sequential anionic polymerization of MsAz and s BsAz with 2-methyl-1-(methylsulfonyl)aziridine (MsMAz) creates P(MsAz-r-s BsAz)-b-P(MeMsAz). Removal of the sulfonyl groups from P(MsAz-r-s BsAz)-b-P(MsMAz) gives lPEI-b-poly(propylenimine). For the first time, lPEI can be synthesized by a controlled anionic polymerization.

The living anionic polymerization of activated aziridines: a systematic study of reaction conditions and kinetics

“…The azaanionic polymerization of activated aziridines was recently established. [4][5][6][7][8][9] To enable anionic polymerization of aziridines, the acidic proton at the nitrogen needs to be substituted by an activating group, e.g. a sulfonamide group (Scheme 1).…”

4‐Styrenesulfonyl‐(2‐methyl)aziridine: The First Bivalent Aziridine‐Monomer for Anionic and Radical Polymerization

“…We demonstrated that steric groups such as C‐10 chains or bulky phenyl groups do not hamper the polymerization . In addition, the electron withdrawing group, which is attached to the aziridine ring by a cleavable sulfonamide, can be used as a handle to control chemical function . The electron withdrawing behavior activates the aziridine and thereby influences the polymerization kinetics .…”

“…[22,25] In addition, the electron withdrawing group, which is attached to the aziridine ring by a cleavable sulfonamide, can be used as a handle to control chemical function. [18,26] The electron withdrawing behavior activates the aziridine and thereby influences the polymerization kinetics. [22] StMAz is estimated to have a similar electron withdrawing behavior as the TsMAz.…”

Full and partial hydrolysis of poly(2-oxazoline)s and the subsequent post-polymerization modification of the resulting polyethylenimine (co)polymers

“…[38][39][40] The branching was minimized by Goethals et al using N-(2-tetrahydropyranyl)aziridine (THPA), which could be cleaved under mild conditions to obtain L-PEI. 41,42 The polymerization of activated sulfonamide aziridines via living anionic polymerization was recently explored by Bergman 43 and Wurm et al 42,44,4546 The obtained polyaziridines or polysulfonamide could partially (desulfonylated) to obtain L-PEI either via hydrolytic cleavage 47 or via reductive removal with a catalyst. 42 Scheme 3.…”