Infrared study of the nature of the copper ion--alkyne bond in Y zeolite

The infrared spectra of acetylene, deuterated acetylene, propyne, and but-2-yne, chemisorbed in Cu, Na--Y zeolites, which have undergone various treatments, were studied. It is concluded that the OH groups interact only with the weakly absorbed molecules, the Cu+ ions are not involved, the acetylenic hydrogen atoms do not take part in the bonding, the Cu2+ ion--alkyne bone results mainly from π donation from the unsaturated hydrocarbon to the metallic ion. (auth)