SYNTHESES, PROPERTIES, AND X-RAY CRYSTAL-STRUCTURES OF IRON AND RUTHENIUM COMPOUNDS WITH THE ETA(5)-C5ME4CF3 LIGAND - COMPOUNDS OF THE TYPE[(ETA(5)-C5ME4CF3)M(MU-CO)(CO)](2) (M=FE, RU)

(Trifluoromethyl)tetramethylcyclopentadiene, HC5Me4CF3 ((CpH)-H-double dagger), reacts with Ru-3(CO)(12) in refluxing n-decane to produce [( eta(5)-C5Me4CF3)Ru(mu-CO)(CO)](2) (1). In chlorinated hydrocarbon solu tions, 1 reacts with the solvents in the presence of visible light to produce [(eta(5)-C5Me4CF3)Ru(CO)(2)(Cl)] (3a). Compound 1 reacts with iodine in refluxing CH2Cl2 to produce [(eta(5)-C5Me4CF3)Ru(CO)(2)(I)] (3b). The X-ray crystal structure of compound 3b is presented. Compoun d 3b reacts with triphenylphosphine in refluxing ethanol to produce [( eta(5)-C5Me4CF3)Ru(CO)(PPh3)(I)] (4). The HC5Me4CF3 ligand reacts with Fe(CO)(5) in refluxing heptane to produce [(eta(4)-HC5Me4CF3)Fe(CO)(3 )] (5). Compound 5 represents a new mode of coordination (eta(4)) for HC5Me4CF3. The spectroscopic properties of compound 1 and its previous ly reported iron analog, [(eta(5)-C5Me4CF3)Fe(mu-CO)(CO)](2) (2), are compared with those of their eta(5)-C5H5 and eta(5)-C5Me5 ''parent'' a nalogs of the type [(eta(5)-C5R5)M(mu-CO)(CO)](2) (M = Fe, Ru). Compou nds 1 and 2 were characterized by single-crystal X-ray crystallography and found to be in the trans configuration with respect to the eta(5) -C5Me4CF3 rings. Overall, the spectroscopic and X-ray structural data of 1 and 2 support the previous conclusions that the eta(5)-C5Me4CF3 l igand is electronically equivalent to eta(5)-C5H5 and sterically equiv alent to eta(5)-C5Me5. Compounds 1 and 3b represent important synthons for subsequent ruthenium chemistry with the eta(5)-C5Me4CF3 ligand.