THE CHEMISTRY OF THE SELENIUM-CONTAINING CLUSTER [RU-4-(MU-4-SE)2(CO)8(MU-CO)3] - CRYSTAL-STRUCTURES OF [RU-3(MU-3-SE)2-(CO)7(PH2PC2PPH2)], [RU-4(MU-4-SE)2(CO)10(SBPH3)] AND [RU-3(MU-3-SE)2(CO)9]

The selenium-containing cluster [Ru4(mu4-Se)2(CO)8(mu-CO)3] 1 may be readily prepared by vacuum pyrolysis of [Ru3(CO)12] with PhSeSePh at 185-degrees-C. The subsequent reaction of 1 with the bidentate phosphine ligand bis(diphenylphosphino)acetylene (dppa) affords the orange triruthenium cluster [Ru3(mu3-Se)2(CO)7(dppa)] 2, in 80% yield. Complex 2 crystallises in the space group P1BAR with a = 12.059(3), b = 12.274(3), c = 13.172(5) angstrom, alpha = 66.78(2), beta = 83.21(3), gamma = 89.30(2)-degrees and Z = 2. Treatment of complex 1 with triphenylantimony, SbPh3, yields the antimony-substituted cluster [Ru4-(mu4-Se)2(CO)10(SbPh3)] 3, in quantitative yield. Complex 3 crystallises in the space group P1BAR with a = 9.474(4), b = 12.456(3), c = 14.913(5) angstrom, alpha = 91.89(2), beta = 93.88(3), gamma = 109.99(3)-degrees and Z = 2. Reaction of cluster 1 with carbon monoxide at room temperature and 70 atm affords the triruthenium selenido-bridged cluster [RU3(mu3-Se)2(CO)9] 4. Complex 4 crystallises in the space group P1BAR with a = 6.887(3), b = 9.606(7), c = 13.567(9) angstrom, alpha = 82.48(6), beta = 84.91 (4), gamma = 68.85(5)-degrees and Z = 2.