Hyperbranched Polyynes:  Syntheses, Photoluminescence, Light Refraction, Thermal Curing, Metal Complexation, Pyrolytic Ceramization, and Soft Magnetization

Homopolycouplings of aryltriynes Ar(C⋮CH)3 and their copolycouplings with monoyne Ar‘C⋮CH are effected by CuCl in air under Glaser-Hay oxidative coupling conditions, giving soluble hyperbranched polyynes (hb-PYs). Hyperbranched poly[tris(4-ethynylphenyl)amine] emits bright blue light (λem = 440 nm) and shows high light refractivity (n = 1.770−1.861). Its peripheral terminal triple bonds can be 100% end-capped by aromatic rings via palladium-catalyzed coupling with aryliodides. The carbon-rich polyynes are readily curable (from ∼150 °C), thermally stable (Td up to ∼550 °C), and pyrolytically carbonizable (Wr up to ∼80% at 900 °C). Complexations with cobalt carbonyls metallify the hb-PYs, and ceramizations of the cobalt−polyyne complexes afford soft ferromagnetic materials with high magnetizability (Ms up to ∼118 emu/g) and low coercivity (Hc down to ∼0.045 kOe).