Treatment of bis(triethylphosphine)nickel dichloride with trifluoropropynylmagnesium iodide affords trans-(Et3P)2Ni(CC·CF3)l. Similarly, from the halides trans-(Et3P)2MCl2(M = Pd or Pt) and (π-C5H5)2TiCl2 the trifluoropropynyl complexes trans-(Et3P)2M(CC·CF3)2 and (π-C5H5)2 Ti(CC·CF3)2, respectively, are obtained. Reaction between dicarbonyl-π-cyclopentadienyliron halides and the appropriate lithium acetylides yields the compounds π-C5H5Fe(CO)2CCR (R = CF3, C6F5, or C6H5). Evidence for the formation of the two complexes RCCRe(CO)5(R = C6F5 or C6H5) has been obtained.