Catalyst-Free Thiol–Yne Click Polymerization:
A Powerful and Facile Tool for Preparation of Functional Poly(vinylene
sulfide)s
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Abstract
The
“thio-click” polymerization is a well-expanded
concept of click polymerization. Among the click polymerizations,
the thiol–yne click polymerization is less developed and still
in its infancy stage. In general, UV light, elevated temperature,
amine, or transition metal complexes is needed to catalyze the thiol–yne
click polymerization, which greatly complicates the experimental operation
and limits its application. In this work, a facile and powerful thiol–yne
click polymerization was developed, which could be carried out under
very mild conditions without using external catalyst. Simply mixing
the aromatic diynes (<b>1a</b>–<b>1e</b>) and dithiols
(<b>2</b>–<b>4</b>) with equivalent molar ratio
in THF at 30 °C will readily produce soluble and regioregular
functional poly(vinylene sulfide)s (P<b>Ia</b>–P<b>Ie</b>, P<b>II</b>, and P<b>III</b>) with high molecular
weights (<i>M</i><sub>w</sub> up to 85 200) in excellent
yields (up to 97%) after as short as 2 h. Furthermore, no double addition
product of an ethynyl group was found. This catalyst-free thiol–yne
click polymerization has remarkably simplified the reaction conditions
and will facilitate the preparation of functional materials applied
in diverse areas