Submerged electric arc between graphite electrodes: a one-pot tool for the synthesis of long-chain polyynes in solution

Polyynes, a class of molecules described by the general formula H–(CC)mH (where m is an integer) can be synthesized using an electric arc between graphite electrodes submerged in an organic solvent such as methanol, n-hexane, n-dodecane, decahydronaphthalene or acetonitrile. When the electric arc is used in acetonitrile at −40 °C, polyyne chains of up to 18 carbon atoms (m=9) have been produced together with monocyanopolyyne as by-product. The polyynes can be reduced to ene–ynes by shaking a hexane solution of them with Zn/HCl.