Abstract
The new compounds {eta-4-C(CH2)3}Fe(CO)2L ((TMM)Fe(CO)2L; L = PPh3, PMePh2, PMe2Ph, PCyPh2, PCy2Ph, PCy3, P(m-xylyl)3, PBz3, t-BuNC) have been synthesized by substitution of CO on {eta-4-C(CH2)3}Fe(CO)3 and are found to be surprisingly stable with respect to thermolysis and air oxidation. All have been characterized by IR and H-1, C-13{H-1}, and P-31{H-1} spectroscopy, and some electrochemically, fluxional behavior involving TMM rotation is observed for several of the compounds. The X-ray crystal structure of (TMM)Fe(CO)2PCy2Ph shows that the TMM ligand assumes a typical ''umbrella-like'' mode of coordination; the internal TMM ligand bond angles and distances differ little from those of other TMM-iron compounds, although the Fe-C distance of the methylene group ''trans'' to phosphorus is marginally longer than the other two iron-methylene distances.