Thermolysis of Ru3(CO)10(µ-dppp): A new Ru4- cluster derived from 1,3-bis(diphenylphosphino)propane

Abstract

The reaction of Ru3(CO)12 and dppp [dppp = 1,3-bis(diphenylphosphino)propane/Ph2P(CH2)3PPh2] in the presence of benzophenone ketyl radical anion afforded [Ru3(CO)11]2(µ-dppp) (1) Ru3(CO)10(µ-dppp) (2), Ru3(CO)9(µ-dppp)(ƞ1-dppp) (3) and Ru3(CO)8(µ-dppp)2 (4). Refluxing 2 in octane yields new triruthenium clusters Ru3(CO)9(μ3-PPh(CH2)3PPh(C6H4)) (5) and Ru4(CO)9(µ-CO){µ4-η2-P(CH2)3PPh2}(µ4-η4-C6H4) (6), as a result of CH and CP bond activation involving the Ph2P(CH2)3PPh2 ligand. Compounds 2 and 6 have been structurally determined by the single crystal X-ray diffraction. As expected, the Ph2PCH2CH2CH2PPh2 ligand in 2 is equatorially bonded to Ru–Ru bond in µ2-η2 mode. In contrast, the X-ray structure of 6 shows an µ4-η2-PCH2CH2CH2PPh2 and a benzyne group coordinated to a square of Ru atoms. A rotation of benzyne group on a square of Ru atoms was supported by variable temperature NMR studies. The topological analysis was performed on 6 to further elucidate their chemical bond properties.