Photolysis of diruthenium hexacarbonyl tetrahedrane compounds in Nujol glass matrices

The photochemistry of five diruthenium hexacarbonyl tetrahedrane compounds, Ru2(CO)6(μ-S2C6H4) (1), Ru2(CO)6(μ-S2C2H4) (2), Ru2(CO)6(μ-S2C3H6) (3), Ru2(CO)6(μ-SCH2CH3)2 (4), and Ru2(CO)6(μ-dmpz)2, (5), where dmpz=3,5-dimethylpyrazolate, have been examined in frozen Nujol glasses at ca. 90 K. Compounds 1–4 are found to lose CO upon UV photolysis to form two isomeric photoproducts, while 5 is found to form one product almost exclusively. The various photoproducts are assigned to axial and equatorial CO-loss species on the basis of the spectra of analogous triphenylphosphine pentacarbonyl derivatives.