-
[show abstract]
[hide abstract]
ABSTRACT: Three new platinum–ruthenium complexes: Pt3Ru3(PBut
3)3(CO)12, 8, Pt5Ru3(PBut
3)3(CO)12, 9 and PtRu3(PBut
3)2(CO)8(μ3-PBut)(μ-H)2, 10 were obtained from the reaction of Ru3(CO)12 with Pt(PBut
3)2. Compound 8 was obtained from this reaction when conducted at 25°C. Compounds 9 and 10 were obtained when the reaction was conducted at 68°C. The structure of 8 consists of a central triangular cluster of three ruthenium atoms with one Pt(PBut
3) group bridging each of the three Ru–Ru bonds. The structure of 9 consists of a capped pentagonal bipyramidal cluster of eight metal atoms that is formed formally by the addition of two platinum
atoms to 8. The structure of 10 contains a triangular cluster of three ruthenium atoms with a Pt(PBut
3) group bridging one of the Ru–Ru bonds. A t-butyl phosphido ligand formed by degradation of a molecule of PBut
3 bridges the three ruthenium atoms.
Journal of Cluster Science 04/2012; 19(1):121-132. · 0.92 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Reactions of the unsaturated mixed metal cluster complex PtOs3(CO)7(PBut3)(μ-PBut2)(μ4-CHCMeCH), 1, with hydrogen, HGePh3, and PhC2H have been investigated. Compound 1 reacts reversibly with hydrogen at room temperature to yield the dihydrido complex PtOs3(CO)7(PBut3)(μ-PBut2)(μ4-CHCMeCH)(μ-H)(H), 2. A computational analysis shows that the hydrogen addition occurs by oxidative addition at the electronically unsaturated platinum atom and passes through two unstable intermediates before giving the final product 2. Compound 1 reacts with HGePh3 at the Ge−H bond to form the complex PtOs3(CO)7(PBut3)(μ-PBut2)(μ4-CHCMeCH)(GePh3)(μ-H), 3, but in this reaction the HGePh3 addition occurred at one of the osmium atoms and a CO ligand was shifted to the platinum atom. Compound 1 reacts with PhC2H by loss of the platinum atom and the PBut3 ligand to give the compound Os3(CO)7(μ-PBut2)[μ3-η5-CHCMeC(H)CCPhH], 4. In the process, the PhC2H molecule became bonded to the CHCMeCH ligand in 1 and its hydrogen atom was shifted to the phenyl-substituted carbon atom to form a triply bridging CHCMeC(H)CCPhH ligand. All of the products were characterized by single-crystal X-ray diffraction analyses.
09/2008;
-
[show abstract]
[hide abstract]
ABSTRACT: The new tetrahedral complex Os4(CO)12[Pd(PBut3)]4, 3, was obtained from the reaction of Os3(CO)12 with Pd(PBut3)2 in octane solution at reflux. Compound 3 was characterized by IR, 1H and 31P NMR spectroscopy, mass spectroscopy, and single-crystal X-ray diffraction analysis. The electronic structure of 3 was evaluated by Fenske–Hall molecular orbital analysis. Compound 3 is electronically unsaturated and reacts with hydrogen at room temperature to yield the known compound Os4(CO)12(μ-H)4, 4.
02/2008;
-
[show abstract]
[hide abstract]
ABSTRACT: When anchored on a high-area, siliceous supports, nanoparticle catalysts, consisting of two or three different metals, but totaling no more than twenty atoms in all, exhibit exceptional activities and selectivities in solvent-free, one-step hydrogenation reactions at low temperatures (< 420 K) and much lower pressures (e.g. 30 bar) than those required in current industrial manufacture. The two selective hydrogenations illustrated here are the conversion of (a) cyclododecatriene (CDT) to cyclododecene (CD) and (b) dimethyl terephthalate (DMT) to cyclohexane dimethanol (CHDM); each of these products is extensively used in the polymer industry. All our mixed-metal nanoparticles are derived from an appropriately chosen parent (precursor) mixed-metal carbonyl having phenyl-containing tin ligands, e.g. Ru4(mu4-SnPh)2(CO)12. Various techniques are used to characterize the denuded, anchored cluster catalysts; and it is expected that aberration-corrected high-resolution electron microscopy (and other techniques, which are outlined) will be invaluable in such characterization. Density functional theory has provided important insights into the structures and electronic properties of our catalysts and their precursors.
Faraday Discussions 02/2008; 138:301-15; discussion 317-35, 433-4. · 5.00 Impact Factor
-
Angewandte Chemie International Edition 02/2007; 46(43):8182-5. · 13.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Three new compounds, Ru4(mu4-GePh)2(mu-GePh2)2(mu-CO)2(CO)8 (11), Ru4(mu4-GePh)2(mu-GePh2)3(mu-CO)(CO)8 (12), and Ru4(mu4-GePh)2(mu-GePh2)4(CO)8 (13), were obtained from the reaction of H(4)Ru(4)(CO)12 with excess Ph(3)GeH in octane (11 and 12) or decane (13) reflux. Compound 11 was converted to compound 13 by reaction with Ph(3)GeH by heating solutions in nonane solvent to reflux. Compounds 11-13 each contain a square-type arrangement of four Ru atoms capped on each side by a quadruply bridging GePh ligand to form an octahedral geometry for the Ru(4)Ge(2) group. Compound 11 also contains two edge-bridging GePh(2) groups on opposite sides of the cluster and two bridging carbonyl ligands. Compound 12 contains three edge-bridging GePh(2) groups and one bridging carbonyl ligand. Compound 13 contains four bridging GePh(2) groups, one on each edge of the Ru4 square. The reaction of H(4)Os(4)(CO)12 with excess Ph(3)GeH in decane at reflux yielded two new tetraosmium cluster complexes, Os4(mu4-GePh)2(mu-GePh2)3(mu-CO)(CO)8 (14) and Os4(mu4-GePh)2(mu-GePh(2))4(CO)8 (15). These compounds are structurally similar to compounds 12 and 13, respectively.
Inorganic Chemistry 02/2007; 46(2):533-40. · 4.60 Impact Factor
