Novel Anionic Ring-Opening Polymerization of Seven-Membered Monothiocarbonate Depending on Initiators

Cationic polymerization of seven‐membered cyclic monothiocarbonate 1,3‐dioxepan‐2‐thione

“…Figure 1 illustrates the 13 C NMR spectra of 7TC and poly(1,3‐dioxepan‐2‐thione) (poly7TC), which clearly indicate the complete transformation of the thiocarbonyl moiety in 7TC at 198 ppm into the carbonyl moiety at 171 ppm upon polymerization. Other peaks in the 13 C NMR spectra and peaks in the 1 H NMR spectra agreed well with the expected structure for poly(7TC) obtained by the anionic polymerization of 7TC with potassium t ‐butoxide 13. IR spectrometric analysis further supported the isomerization.…”

“…However, the higher reactivity of sulfur‐containing monomers and the poor solubility of the resulting polymers often regulate versatility in the design of sulfur materials. To overcome this problem, we have developed the polymerization of a variety of sulfur‐containing monomers 5–17. The cationic polymerization of five‐membered cyclic dithiocarbonates has been reported to produce the corresponding polymers if carbocationic initiators are used, whereas protonic and Lewis acids predominantly lead to specific isomerization reactions 5, 6.…”

“…The control of the polymerization of six‐membered cyclic monothiocarbonates has required the monomers to carry appropriate substituents 9, 10. In contrast, the living anionic polymerization of a seven‐membered cyclic monothiocarbonate, 1,3‐dioxepan‐2‐thione (7TC), can be conducted by the appropriate choice of the initiator to afford a soluble poly(thiocarbonate) 13. Because the sulfur‐containing monomers mentioned previously were polymerized by cationic initiators, we examined the cationic polymerization behavior of 7TC.…”

Recent advances in the ring-opening polymerization of sulfur-containing monomers

“…66 The anionic ROP of M32 in the presence of KOtBu provided the corresponding polythiocarbonate (M n = 8.8 kg mol −1 , Đ = 1.07) in quantitative yield, demonstrating the controlled nature of polymerization. 67 The molecular weight of polyM32 was reported to increase linearly with monomer conversion, retaining a narrow molecular weight distribution. The cationic ROP of monomers M30 and M31 bearing fused-and spiro-adamantane moieties was also reported; for example the M n and dispersity value obtained by the ROP of M30 with H 2 O/BF 3 •Et 2 O were 10.6 kg mol −1 and 1.44, respectively.…”