Room Temperature Multicomponent Polymerizations of Alkynes, Sulfonyl Azides, and Iminophosphorane toward Heteroatom-Rich Multifunctional Poly(phosphorus amidine)s

Multicomponent
polymerization (MCP) is a fascinating synthetic
method for the construction of polymers with diverse structures and
multifunctionalities. As a rapidly developing field, MCP begins to
show great impact in polymer chemistry and polymer materials, which
attract scientists’ attention by their high convenience and
efficiency, great structure diversity, high atom economy, and environmental
benefit. In this work, a facile one-pot three-component polymerization
of diynes, disulfonyl azides, and iminophosphorane is developed to
construct N, O, S, and P-containing heteroatom-rich poly­(phosphorus
amidine)­s with advanced functionalities. The optimized MCP proceeds
at room temperature in THF under the catalysis of CuI, generating
polymers with high molecular weights (up to 85 600 g/mol) in
excellent yields (up to 92%). The MCP enjoys general applicability
of various monomers including aromatic and aliphatic alkynes, and
the only byproduct generated from the polymerization is nitrogen gas,
demonstrating high atom economy and environmental benefit. Interestingly,
the phosphorus amidine model compounds were found to possess both
aggregation-induced emission behavior and thermally activated delayed
fluorescence, indicating unique feature of the corresponding polymer
materials. The polymers generally enjoy good solubility in polar organic
solvents, good film-forming ability, satisfactory thermal stability,
and high refractivity. They can also function as fluorescent chemosensors
for Pd2+ ions detection with high sensitivity (Kq up to 207 600 M–1) and selectivity. This MCP provides an efficient approach for the
synthesis of heteroatom-rich multifunctional polymer materials, which
directly construct the luminescent phosphorus amidine moiety in situ,
demonstrating high synthetic efficiency and the potential application
in material science.