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 (M_w 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 (ν_D' 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.