Notes. Reaction of triruthenium dodecacarbonyl with nitrobenzene and structure of µ₃-phenylnitrene-triruthenium decacarbonyl, [Ru₃(CO)₁₀(µ₃-NPh)]

Triruthenium dodecacarbonyl [Ru3(CO)12] reacts with nitrobenzene to give [Ru3(CO)10(NPh)](3) and [Ru3(CO)9(NPh)2](4) in low yields, accompanied by formation of CO2. The solution i.r. spectrum of (3) suggests the presence of triply bridging NPh and CO groups, confirmed by a single-crystal X-ray structure determination; space group P21/n, a= 12.457(1), b= 11.428(1), c= 29.234(2)Å, β= 92.38(1)°, Z= 8, and R= 0.036 for 4 817 unique observed reflections. The two independent molecules differ slightly in the relative orientations of the phenyl groups. Mean bond lengths include Ru–Ru 2.746(5), Ru–µ-C 2.172(8), and Ru–µ-N 2.055(5)Å. The i.r. Spectra of complexes (3) and (4) are discussed in terms of a molecular-orbital description of ' M3(CO)9' moieties.