Metal‐Free Alkyne Polyhydrothiolation: Synthesis of Functional Poly(vinylenesulfide)s with High Stereoregularity by Regioselective Thioclick Polymerization

Abstract

A new synthetic route to sulfur‐rich polymers has been developed. The alkyne polyhydrothiolations of 4,4′‐thiodibenzenethiol (1) and arylene dipropiolates (2–5) mediated by amines proceed at room temperature in a regioselective fashion, furnishing sole anti‐Markovnikov products of poly(vinylenesulfide)s (P1/2–P1/5) with high molecular weights (Mw up to 32 300) and high stereoregularities (Z content up to 81.4%) in high yields (up to 98.2%). Polymers P1/2–P1/4 are soluble in common organic solvents. They are optically transparent, allowing almost all visible and IR light to transmit through. Thanks to the high sulfur contents of the polymers, their films show high refractive indices (n = 1.73–1.70) in the wavelength region of 500–1700 nm as well as high Abbé numbers (νD' up to 539) and low optical dispersions (D' down to 0.002) at wavelengths important for telecommunications. Their refractivities can be further enhanced (n up to 2.06) by metal complexation and their films can be crosslinked by UV irradiation, which enables ready fabrication of fluorescent photopatterns.

Thiol-yne click polymerization

“…We thus successfully established the metal-free click polymerizations [35][36][37][38][39]. In 2010, we also established a novel aminemediated thiol-yne click polymerization [17]. According to reported theory, propiolates are an inert alkyne when reacting with thiols via radical mediated mechanism [40].…”

“…Moreover, the thiol-yne click reaction has the additional feature that two thiol groups could react with one ethynyl group via well-known two-step processes, and fully additive products with branched structures will be yielded [16]. Meanwhile, the mono-additive products of vinyl sulfides could also be obtained when the reactions were carried out between aromatic alkyne and thiols [17,18]. Theoretically, there are regio-and stereo-isomers of the yielded vinyl sulfides, as shown in Figure 1, which could be well-controlled by catalyst selection.…”

“…Indeed, the thiol-yne click reaction has been used to synthesize functional polymers with sulfurcontaining linear and topological structures [17][18][19][20][21][22][23][24][25][26][27][28], which have been widely applied in diverse areas [17,18,29]. While, to our best knowledge, there is no review to summarize its recent progress.…”

Click Chemistry: A Powerful and Versatile Methodology for Preparation of Ferrocene-Containing Polymers

“…The removal of the copper residues after Cu(I)-catalyzed AACP is, however, difficult. To surmount this difficulty, we have successfully established the metal-free AACPs of activated alkynes and azides [67][68][69][70][71][72][73]. Recently, we employed the metal-free AACP of propiolates and azide to prepare Fc-containing poly(aroxycarbonyltriazole)s (PACTs) [74].…”

Progress on Catalytic Systems Used in Click Polymerization

“…Together with the devolvement of base participated azide‐alkyne click polymerization, an efficient organobase‐mediated thiol‐yne click polymerization to furnish the regioregular and stereoregular PVSs was established as well . As shown in Scheme , the diphenylamine‐mediated polyhydrothiolations of arylene dipropiolates and 4,4‐thiodibenzenethiol 84 propagated smoothly in a regiospecific fashion at room temperature without exclusion of air and moisture, and the anti‐Markovnikov additive PVSs with high molecular weights and good stereoregularities ( Z ‐isomer content up to 81%) were produced in good yields.…”