PLATINUM-ACETYLENE COMPLEXES .2. MONOSUBSTITUTED HYDROXYACETYLENES

The reactions of some α-hydroxyacetylenes with the complexes tetrakis(triphenylphosphine)platinum(0), I, and cis-dichlorobis(triphenylphosphme)platinum(II), II, have been studied. Reaction of either I or II under appropriate conditions with 1-ethynylcyclopentanol, 1-ethynylcyclohexanol, 1-ethynylcycloheptanol, 3-methyl-1-butyn-3-ol, 1,1-diphenyl-2-propynl-ol, and 3-methyl-1-pentyn-3-ol yielded complexes containing μ-bonded acetylenes. The C≡C stretching frequency of the complexed acetylene in the infrared spectrum is lowered by about 400 cm-1 over that of the free acetylene and the acetylenic proton appears in the nmr spectrum as an AA′MX type of multiplet centered at T ̃3.7 ppm. Mechanistic implications are presented and discussed. © 1969, American Chemical Society. All rights reserved.