Photolytic hydrogenation of the polyynes C6H2, C8H2, C10H2, and C12H2 in n-hexane with 253.6 nm radiation

Abstract The polyynes C 6 H 2 , C 8 H 2 , C 10 H 2 , and C 12 H 2 in n -hexane exposed to 253.6 nm radiation “disappear” much faster in air-free solutions than in solutions in equilibrium with air. These observations suggest that the disappearance is due to reaction of the polyyne molecules in the ground state with a photolytically produced chemical species which in solutions in equilibrium with air is overwhelmingly scavenged by dissolved O 2 . Although no hydrogenation products were firmly established the most likely chemical is atomic hydrogen.