Antonia Neels

Amphiphilic organoruthenium oxomolybdenum and oxovanadium clusters

Abstract Para-cymene ruthenium dichloride dimer reacts in aqueous solution with sodium molybdate or sodium vanadate to give the amphiphilic clusters [ (η6-p-MeC6H4i Pr) 4Ru4Mo4O16] (1) and [ (η6-p-MeC6H4i Pr) 4 Ru4V6O19] (4) respectively. The analogous reaction of hexamethylbenzene ruthenium dichloride dimer with sodium vanadate gives [ (η6-C6Me6) 4Ru4V6O19] (5) . The mixed-metal clusters [ (η6-p-MeC6H4i Pr) Ru (η5-C5Me5) 3Rh3Mo4O16] (2) and [ (η6-p-MeC6H4i Pr) 2Ru2 (η5-C5Me5) 2Rh2Mo4O16] (3) are accessible from a mixture of para-cymene ruthenium dichloride dimer and pentamethylcyclopentadienyl rhodium dichloride dimer with sodium molybdate in aqueous solution. The crystal structure analyses of 1 and 4 reveal different framework geometries of the metal oxygen skeletons. 17O NMR spectroscopy and partial charge calculations confirm the presence of three different types of oxygen atoms in 1.

Metal-framework degradation reactions of the mixed-metal cluster anions [M3Ir(CO)13]− (M=Ru, Os) with bis(diphenylphosphino)methane and with tricyclohexylphosphine: synthesis and structure of HRu2Ir(CO)5(dppm)3, HRu2Ir(CO)6(PCy3)3, H2Os2Ir2(CO)10(PCy3)2 and H3Os3Ir(CO)8(PCy3)3

Abstract The mixed-metal cluster anions [M3Ir(CO)13]− (M=Ru, Os) react in methanol under metal-framework degradation with bis(diphenylphosphino)methane (dppm) or tricyclohexylphosphine (PCy3) to give a series of neutral tri- and tetranuclear mixed-metal clusters. The reaction of [M3Ir(CO)13]− (M=Ru, Os) with dppm leads to the phosphine-substituted hydrido derivatives HRu2Ir(CO)5(dppm)3 (1) and HOs2Ir(CO)5(dppm)3 (2), respectively. The two 48e clusters show a triangular arrangement of the M2Ir skeleton. The dppm ligands are coordinated in bridging positions over each metal–metal edge; the hydride is bonded terminally to the iridium atom. Cluster degradation is also observed by treating [Ru3Ir(CO)13]− with PCy3 in methanol, giving the highly electron-deficient (44e) mixed-metal cluster HRu2Ir(CO)6(PCy3)3 (3). The reaction of the osmium homologue [Os3Ir(CO)13]− with PCy3 under the same conditions leads to a mixture of the neutral tetranuclear clusters H2Os2Ir2(CO)10(PCy3)2 (4) and H3Os3Ir(CO)8(PCy3)3 (5). Both clusters, 4 and 5 still have a tetrahedral metal core like the starting cluster anion but in 4 an osmium atom has been replaced by an iridium atom. The molecular structures of 1, 3, 4 and 5 were confirmed by single-crystal X-ray structure analyses.

Electron-deficient triruthenium and triosmium clusters from the reaction of the cluster anions [HM3(CO)11]− (M=Ru, Os) with tricyclohexylphosphine in methanol

Abstract The reaction of Na[HRu 3 (CO) 11 ] with an excess of tricyclohexylphosphine in methanol gives the neutral complex H 2 Ru 3 (CO) 6 (PCy 3 ) 3 which is the first 44 e − triruthenium cluster reported. This highly electron-deficient species reacts with carbon monoxide to give the saturated 48 e − cluster Ru 3 (CO) 9 (PCy 3 ) 3 . The electronic structure of the novel 44 e − cluster was established by EHT and DFT molecular orbital calculations of isoelectronic model compounds. The analogous reaction of [N(PPh 3 ) 2 ][HOs 3 (CO) 11 ] with PCy 3 in methanol affords the 46 e − cluster H 2 Os 3 (CO) 7 (PCy 3 ) 3 , the first trisubstituted derivative of H 2 Os 3 (CO) 10 . In all cases methanol acts as source of protons for the formation of the hydrido clusters.

Diethyl N,N'-(Naphthalene-1,8-diyl)dioxamate

The reaction of ethyloxalyl chloride and naphthalene-1,8-diamine in refluxing tetrahydrofuran yielded the title compound, C 18 H 18 N 2 O 6 . The crystal structure analysis reveals a molecule with one oxamate substituent nearly coplanar with the aromatic naphthalene system, while the second is strongly twisted with respect to the naphthalene system. Three strong intramolecular hydrogen bonds are observed, one in each oxamic acid ethyl ester group and one linking the two substituents. Symmetry-related molecules are connected by a fourth intermolecular hydrogen bond.

1,4-Bis(hex­yloxy)-2,5-diiodo­benzene

The centrosymmetric title compound, C18H28I2O2, crystallized in the monoclinic space group P21/c with the alkyl chains having extended all-trans conformations, similar to those in the centrosymmetric bromo analogue [Li et al. (2008 ▶). Acta Cryst. E64, o1930] that crystallized in the triclinic space group P . The difference between the two structures lies in the orientation of the two alkyl chains with respect to the C(aromatic)—O bond. In the title compound, the O—Calkyl—Calkyl—Calkyl torsion angle is 55.8 (5)°, while in the bromo analogue this angle is −179.1 (2)°. In the title compound, the C-atoms of the alkyl chain are almost coplanar [maximum deviation of 0.052 (5) Å] and this mean plane is inclined to the benzene ring by 50.3 (3)°. In the bromo-analogue, these two mean planes are almost coplanar, making a dihedral angle of 4.1 (2)°. Another difference between the crystal structures of the two compounds is that in the title compound there are no halide⋯halide interactions. Instead, symmetry-related molecules are linked via C—H⋯π contacts, forming a two-dimensional network.

Saturated and unsaturated tetraruthenium clusters containing sterically demanding dicyclohexylphosphido ligands: synthesis and structure of [H4Ru4(CO)8(PCy2)4] and [H5Ru4(CO)8(PCy2)3]

The thermal reaction of the dinuclear complex [Ru2(CO)4(O2CH)2(PCy2H)2] with molecular hydrogen in cyclohexane afforded the tetranuclear clusters [H4Ru4(CO)8(PCy2)4] (64e) and [H5Ru4(CO)8(PCy2)3] (62e), both of which have a square-planar arrangement of the metal framework.