Hyperbranched Polyynes Containing Cobaltcarbonyls as Precursors to Nanostructured Magnetoceramics

Facile complexation of the acetylenic triple bonds in the hyperbranched polyynes (hb-PYs) with cobalt carbonyls readily furnishes cobalt-containing organometallic polymers at room temperature. The cobalt-polyyne complexes are highly resistant to thermolysis. Pyrolyses of the polyyne complexes under nitrogen afford soft ferromagnetic ceramics with high magnetizability (Ms up to ~118 emu/g) and low coercivity (Hc down to ~0.045 kOe).