Novel triethylamine catalyzed S → O acetyl migration reaction to generate candidate thiols for construction of topological and functional sulfur-containing polymers

Wang, Gang; Peng, Li; Zheng, Yaochen; Gao, Ying; Wu, Xuedong; Ren, Tianhui; Gao, Chao; Jin, Han

doi:10.1039/c4ra09842k

Cited by 15 publications

(10 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In light of this, we decided to take advantage of the neighboring alcohol produced from the ring opening to perform an intramolecular acetyl migration. Exploring the conditions of Han and co-workers, we were able to successfully deprotect over 90% of the thiols through a sulfur to oxygen acetyl migration to yield the thiolated polymer scaffold 5 (Scheme S1). With the thiolated acrylate-based polymers in hand, we advanced to explore the construction of the photogrowable nanonetworks (PGNNs) through thiol-maleimide cross-linking reactions.…”

mentioning

confidence: 99%

Photocontrolled Growth of Cross-Linked Nanonetworks

Lampley

Harth

2018

ACS Macro Lett.

View full text Add to dashboard Cite

We report the preparation of photoresponsive nanomaterials and the increase of their nanoscopic size through a “photogrowth” mechanism. The photogrowable nanonetworks (PGNNs) were synthesized by cross-linking two components, a thiolated acrylate copolymer and a symmetrical bismaleimide trithiocarbonate (TTC), utilizing thiol-maleimide click chemistry. With this strategy, nanonetwork growth was achieved through a photoinduced polymerization from the integrated trithiocarbonate by either direct photolysis or photoredox catalysis. Via direct photolysis, we generated a series of expanded particles by polymerizing methyl acrylate (MA) under irradiation with violet light (400 nm) over a period of 1, 3, and 6 h, starting from a 58 nm parent particle, resulting in particles of increased sizes of 77, 156, and 358 nm, respectively. Nanoparticle expansion reactions catalyzed by 10-phenylphenothiazine (PTH) were experienced to progress faster in 20 and 30 min to reach particle sizes of 195 and 300 nm. The addition of the photoredox catalyst to the expansion polymerizations with MA resulted in an increased control over the dispersity of the particles as well as of the promoted disassembly products. In this work, we demonstrated that nanoparticle structures designed as cross-linked networks with integrated trithiocarbonates can be expanded by photocontrolled radical polymerizations (photo-CRPs) in the presence or absence of a photoredox catalyst. These proof-of-concept experiments showcase the dynamic growth and integration of functional units into existing scaffolds and open up the possibility to prepare highly tailorable nanomaterials.

show abstract

mentioning

confidence: 99%

Photocontrolled Growth of Cross-Linked Nanonetworks

Lampley

Harth

2018

ACS Macro Lett.

View full text Add to dashboard Cite

show abstract

“…(v) 3-(Acetylthio)-2-hydroxypropyl methacrylate (TEHMA) was synthesized according to a previously reported procedure . Shortly, in methylene chloride solution thioacetic acid (1.8 g, 22 mmol) and glycidyl methacrylate (20 mmol) were reacted in the presence of TEA (1 mmol) for 10 h at room temperature.…”

Section: Experimental Sectionmentioning

confidence: 99%

“…(v) 3-(Acetylthio)-2-hydroxypropyl methacrylate (TEHMA) was synthesized according to a previously reported procedure. 20 Shortly, in methylene chloride solution thioacetic acid (1.8 g, 22 mmol) and glycidyl methacrylate (20 mmol) were reacted in the presence of TEA (1 mmol) for 10 h at room temperature. After this period, the mixture was washed with 1 M HCl aqueous solution, saturated NaHCO 3 , and DI water and dried over anhydrous Na 2 SO 4 .…”

Section: Synthesis Of Monomers (I)mentioning

confidence: 99%

Thermal Metamorphosis in (Meth)acrylate Photopolymers: Stress Relaxation, Reshaping, and Second-Stage Reaction

et al. 2019

View full text Add to dashboard Cite

Thermally transformable/responsive (meth)acrylate photopolymer networks were constructed from commercial (meth)acrylate esters and synthetic di- and mono(meth)acylate monomers bearing thioester functionalities. The thermal responsiveness, here self-limited exchange, relied on the catalytic metamorphosis of thioesters into esters with the concomitant depletion of hydroxyls and subsequent generation of free thiols. The thioester–hydroxyl cross-exchange was demonstrated in network systems with interchain thioesters as well as in networks with side-chain pendant thioacetyls. The interchain metamorphosis resulted in close to 80% conversion of thioesters into esters when 2 equiv of hydroxyl groups was initially present. In practical terms, such an outcome enabled efficient stress relaxation (60%) and good shape adaptation (90% shape fixity) in 1 h at 105 °C. On the other hand, side-chain S → O acyl transfer reactions were found to vary in efficiency depending on the vicinity of thioesters and hydroxyls. When in close vicinity, efficient noncatalytic exchange was observed in materials with 1-to-1 thioester-to-hydroxyl ratios nearing 60%. The benefits of generating free thiols postpolymerization were further explored in enhanced two-stage curing systems where a subsequent thiol–ene photopolymerization was demonstrated at ambient as well as at elevated temperatures.

show abstract

“…M. Abbasi reported a silica gel/triethylamine combined catalyst for the acetyl migration reaction in 2012, and claimed that the presence of only silica gel or triethylamine would lead to rather low yields and serious side effects. 9 On the contrary, our group promoted the reaction conversions to over 86% with a sole triethylamine system, 10 and to near 100% with a neat graphene oxide aerogel. 11 Clearly, the silica gel used in this study has proven to be more efficient (>92%) and greener compared with triethylamine, and more available and much cheaper compared with GO aerogel, showing industrial application potential.…”

mentioning

confidence: 93%

“…Then the labile large ring instantly disassociates into a 5-membered ring intermediate, 13 plus Si-OH (III). Because sulfur is easier to be polarized than oxygen, 10 the ring opening occurs more often with the cleavage of S-C bonds than that of O-C bonds. Thus, the unstable 5-membered ring transforms into the thiol product immediately (IV).…”

mentioning

confidence: 99%