Lowering the temperature of a Nujol solution of (η5-C5H5CH3Ru 2(CO)4 containing bands of the trans- and cis-bridging and trans-nonbridging isomers from room temperature to ca. 90 K results in complete disappearance of the bands of the trans-terminal isomer. The photochemistry of (η5-C5H4CH3)2Ru 2(CO)4 in frozen Nujol at 90 K differs subtly from that of (η5-C5H5)2Ru 2(CO)4 in inert gas matrixes at 12 K in that the trans-bridging isomer is found to undergo photolysis at high energy (λirr > 250 nm) to yield both the triply bridged carbonyl-loss species, (η5-C5H4CH3)2Ru 2(μ-CO)3, and the cis-bridged species isomer. There is no evidence for formation of the trans-nonbridged isomer upon photolysis as observed for (η5C5H5)2Ru2(CO) 4. The solution photochemistry of (η5-C5H5)2Os 2(CO)4 is shown to closely parallel that of (η5-C5H5)2Ru 2(CO)4. Photolysis of (η5-C5H5)2Os 2(CO)4 in CHCl3 yields (eta;5C5H5)Os(CO)2Cl, while photolysis in benzene yields hydride products believed to arise from metal-to-ring coupling of radicals. Photolysis of (η5-C5H5)2Os 2(CO)4, which exists only in a nonbridged form, in frozen Nujol (90 K) results in CO loss and formation of (η5-C5H5)2Os 2(μ-CO)3 as the only photoproduct. Photolysis of (η5-C5H5M(CO)2H, where M = Ru or Os, in frozen Nujol yields (η5-C5H5)M(CO)H and a second product that appears to be either (η5C5H6)M(CO)2 or the (η5-C5H5)M(CO)2 radical.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry