1,721,005 research outputs found
ALLYLIC AMINATION OF UNACTIVATED OLEFINS BY NITROARENES, CATALYZED BY RUTHENIUM COMPLEXES. A REACTION INVOLVING AN INTERMOLECULAR C-H FUNCTIONALIZATION
No full textORGANOMETALLIC
Deactivation of a [PPN][Rh(CO)(4)]-based catalytic system [PPN+ = (PPh3)(2)N+]. The first decomposition reaction of PPN+ and the formation of [Rh10P(CO)(22)](3-)
No full textAb initio XRPD structure determination of organometallic compounds: The case of Pd(Phen)(C(O)N(Me)OC(O)), a model intermediate in the palladium-phenanthroline-catalyzed reductive carbonylation of aromatic nitro compounds
No full textIn the absence of suitable single crystals, the problem of determining the connectivity pattern of the title compound (and of its phenyl analogue), i.e. that of discriminating between two markedly different stereoisomers, has been solved by the powder diffraction technique. The structure of Pd(Phen)(C(O)N(Me)OC(O)) was solved by ab initio XRPD methods and refined by the Rietveld technique down to Rwp = 0.123, Rp = 0.087, and RF = 0.061 for 5000 data points (847 reflections) collected in the 8 < 2 θ < 108° range. The diffraction results have been cross-validated by steric energy computations within the field of the given crystal lattice
[Rh(CO)4]-, [Rh5(CO)15]- and bimetallic clusters as catalysts for the carbonylation of nitrobenzene to methyl phenylcarbamate
No full textAMINATION OF BENZYLIC C-H BONDS BY ARYLAZIDES CATALYZED BY CO-(II)-POR-PHYRIN COMPLEXES: A SYNTHETIC AND MECHANISTIC STUDY
No full textCHEM-EUR
Solving simple organometallic structures solely from x-ray powder diffraction data: The case of polymeric [{Ru(CO)4}n]
No full textThe crystal and molecular structure of [{Ru(CO)4}n] has been determined solely from X-ray powder diffraction data using standard laboratory equipment and refined with a (modified) Rietveld procedure. The compound crystallizes in the orthorhombic space group Ibam, with a = 14.147(4), b = 7.060(2) and c = 5.720(1) Å, Z = 4; the final refinement (19 variables) converged to Rp, Rwp and RBragg of 0.077, 0.102 and 0.025, respectively, for 4001 data collected at room temperature in the 5-85° (2θ) range. The structure, which consists of a polymeric stack of staggered trans-D4h Ru(CO)4 fragments separated by a Ru-Ru contact of 2.860(1) Å, is the first polymeric binary metal carbonyl compound so far characterized. Strain and particle-size broadening effects have been observed, and the microstructural properties of the compound are discussed
Ab Initio XRPD Structure Determination of Metal Carbonyl Clusters: The Case of [HgRu(CO)4]4
No full textThe crystal and molecular structure of the new [HgRu(CO)4]4 cluster has been determined exclusively from X-ray powder diffraction data from standard laboratory equipment and refined with a (modified) Rietveld procedure. The title compound crystallizes in the monoclinic space group P21/n, with a = 13.032(1) Å, b = 18.293(2) Å, c = 6.501(1) Å,β = 111.81(2)°, V = 1438.9(4) Å3, and Z = 2; the final refinement converged to Rp and Rwp values of 0.097 and 0.126, respectively, for 3351 data collected (Cu Kα) at room temperature in the 18–85° (2θ) range. [HgRu(CO)4]4 consists of a planar, centrosymmetric, eight-membered ring of alternating Hg and cis-Ru(CO)4 units of idealized D4h symmetry. XRPD is shown to be a powerful tool to obtain useful structural information on moderately complex organometallic systems, when single crystals cannot be grown, if all the available chemical knowledge is included in the refinement through constraints. © 1993, American Chemical Society. All rights reserved
Amination of benzylic C-H bonds by aryl azides catalysed by Co(II)(porphyrin) complexes. A new reaction leading to secondary amines and imines
No full textLe Metalloporfirine: un efficace modello di enzimi naturali. Studio meccanicistico della reazione catalitica di amminazione di gruppi benzilici
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