C₆₀-containing poly(1-phenyl- 1-alkynes): Synthesis, light emission, and optical limiting

While polymerizations of 1-phenyl-1-propyne (PP) and 1-phenyl-1-butyne (PB) initiated by WCl₆-Ph₄Sn at room temperature yield small amounts of polymers (0.05-5.3%) with low molecular weights (M(n) 8000-15000) and high polydispersity indexes (PDI up to 109), addition of C₆₀ into the initiator mixture dramatically boosts its catalytic activity, producing polymers with high M(n)s (up to 171 000) and low PDIs (down to 2.2) in high yields (up to 99.5%). The resultant polymers are soluble, stable, and film-forming. GPC, IR, NMR, UV, and XRD analyses reveal that the polymers consist of polyacetylene chains and covalently bound C₆₀ cages (up to 9.1 wt %). Whereas photoluminescence of C₆₀-containing polyPPs is faint, C₆₀-containing polyPBs emit strong blue light (λ(max) = 456 nm) readily observable with the naked eye under normal laboratory lighting. Compared with the parent C₆₀, both two groups of the fullerene polyacetylenes show better optical limiting performance, and their THF solutions, with higher linear transmittance, attenuate the power of intense 532 nm optical pulses to lower saturation fluence.