Preparation of long-chain polyynes of C28H2 and C30H2 by liquid-phase laser ablation

We have prepared long-chain polyynes of C28H2 and C30H2 by liquid-phase laser ablation under the following conditions. A graphite rod was used as a target because it was hard to decrease the amount of impurities that were also produced during ablation, preventing production of long-chain polyynes. A glass bottle with a large diameter of ϕ26 mm was used as a reaction container to decrease the depth of liquid solvent, resulting in an increase in polyyne production. For chromatography, the mobile phase (hexane:ethanol = 600:1 (v/v)) and a long column (ϕ4.6 mm × 250 mm) were used to improve the separation capacity for detection of long-chain polyynes. This is the first report of detection of C30H2 using an UV–vis absorption spectrum and a chromatogram.

► We have prepared polyynes up to C30H2 by liquid-phase laser ablation.
► This is the first report of detection for C28H2 and C30H2 using UV–vis absorption specta.
► A long column and a mobile phase (hexane:ethanol = 600:1 (v/v)) were used to improve chromatographic separation.