1,721,047 research outputs found
Application of the ligand polyhedral model to dicobalt octacarbonyl
No full textApplication of the ligand polyhedral model (LPM) to dicobalt octacarbonyl, [Co2(CO)8], leads to an explanation of the mu-2-bridged structure that the molecule adopts in the solid state and also of the isomeric forms which coexist in equilibrium in solution. It further provides a convenient explanation of both the observed low energy interconversion of these isomers and the fluxional behaviour they exhibit
APPLICATION OF THE LIGAND POLYHEDRAL MODEL TO THE FLUXIONALITY OF FE3(CO)10(CNCF3)(L) (L=CO,PME3,PET3,P(OME)3,P(OET)3
No full textThe fluxionality observed for the triiron carbonyl clusters Fe3(CO)10(CNCF3)(L) (L = CO, PMe3, PEt3, P(OMe)3, P(OEt)3) has been reassessed in the light of the ligand polyhedral model
FLUXIONAL BEHAVIOR OF THE CARBONYLS [M3(CO)12] (M = FE, RU OR OS)
No full textA study of the crystal structures of the carbonyls [M3(CO)12] (M = Fe, Ru or Os) and a series of their derivatives [M3(CO)12-nLn] has revealed good evidence in support of the hypothesis that the mechanism of ligand fluxionality goes via the intermediacy of an anticubeoctahedral complementary geometry. Several examples of systems with an icosahedral distribution of ligands and quasi-D3 symmetry have been identified providing additional support for our earlier suggestion that a second isomer of [Fe3(CO)12], which exists in solution, adopts a similar D3 structure
NA2[RU(NO2)4(NO)(OH)].2H2O - A REDETERMINATION
No full textDisodium hydroxotetranitro(nitroso)ruthenate(III) dihydrate, M(r) = 414.1, monoclinic, C2/m, a = 12.8765 (6), b = 14.5867 (9), c = 7.4478 (4) angstrom, beta = 121.521 (3)-degrees, V = 1192.5 angstrom 3, Z = 4, D(x) = 2.306 Mg m-3, lambda-BAR(Mo K-alpha) = 0.71073 angstrom, mu = 1.430 mm-1, F(000) = 808, T = 298 K, R = 0.0251 for 1760 unique observed reflections. We have redetermined the structure of the title compound by single-crystal X-ray diffraction. After recalculation of the bond lengths derived in the neutron diffraction study, the distances involving the non-H atoms show no significant differences between the two determinations
STEREOCHEMICAL CHANGES IN MONONUCLEAR COMPLEXES ML(N) (N=10-12)
No full textThe process of edge-cleavage (simple and multiple), recently applied to generate complementary geometries for complexes ML(n) (n = 4-9), has been extended to include values of n = 10-12
THE SYNTHESIS AND CHARACTERIZATION OF THE OCTARUTHENIUM-BENZENE CLUSTER [RU8H4(CO)(18)(ETA(6)-C6H6)]
No full textThe reaction of cyclohexene, C6H10, with RU(3)(CO)(12) yields the new octaruthenium-benzene cluster [RU(8)H(4)(CO)(18)(eta(6)-C6H6)] which has been fully characterised in solution,by conventional spectroscopic methods and in the solid state by a single crystal X-ray diffraction analysis
REDETERMINATION OF THE STRUCTURE OF POTASSIUM TETRANITROPALLADATE(II)
No full textK2Pd(NO2)4, M(r) = 368.58, monoclinic, P2(1)/c, a = 9.254 (5), b = 12.747 (3), c = 7.805 (2) angstrom, beta = 96.43 (2)-degrees V = 914.9 angstrom3 [from setting angles for 14 0kl and 12 h0l data, 20 = 18-340, lambda(Mo Kalpha) = 0.71073 angstrom], Z = 4, D(x) = 2.676 Mg m-3, mu = 2.95 mm-1, F(000) = 704, T = 295 K, R = 0.031 for 2327 unique observed reflections. There are two crystallographically independent Pd(NO2)42- ions, each square planar with symmetry 1BAR (C(i)); Pd-N distances are in the range 2.018 (2)-2.047 (2) angstrom
Solid-state studies into the possible rearrangement mechanisms for the fluxional behaviour of the tetranuclear carbonyls M4(CO)12 and their derivativesSolid-State Studies into the Possible Rearregment Mechenisms for the Fluxional Behavior of the Tetranuclear Carbonyls M4 (CO)12 and Their Derivatives
No full textThe deformation from an idealised geometry, observed in the solid state for a given cluster species, may indicate the paths taken by the cluster in ligand fluxionality processes. A number of single-crystal X-ray structures of M4(CO)12-n(L)n clusters (M = Co, Rh, Ir; n = 1-5) have been examined in order to elucidate any geometric trends in their ligand envelope deformations. It has been revealed that the complementary geometries adopted by M4(CO)12-n(L)n species may be both metal- and ligand-dependent. Iridium species adopt T(d)-cubeoctahedral structures, but the available data provide no clear picture for the complementary geometry adopted by cobalt or rhodium species. Additionally, tripodal ligands have been shown to stabilise D3h (icosahedral) ligand polyhedra
The structures and fluxional behaviour of the binary carbonyls; A new approach. Part 3. The fluxional behaviour of [Fe3(CO)11L], L = PR3 or P(OR)3
No full textSEQUENTIAL SYNTHESIS OF SOME TETRAOSMIUM ARENE CLUSTERS
No full textOn activation with Me3NO the tetrahydrido-tetranuclear cluster [Os4(mu-H)4(CO)12] 1 underwent reaction with cyclohexa-1,3-diene in CH2Cl2 under ambient conditions to give, as the major products, the four organometallic clusters [Os4(mu-H)3(CO)11(eta3-C6H9)] 2, [Os4(mu-H)2(CO)12(eta2-C6H8)] 3, [Os4(mu-H)2(CO)11(eta4-C6H8)] 4 and [Os4(mu-H)2(CO)10(eta6-C6H6)] 5. On heating in hexane, 3 is converted into 4 and subsequently 4 into 5. Compound 5 underwent further reaction with Me3NO in CH2Cl2 in the presence of cyclohexa-1,3-diene to produce [Os4(CO)9(eta6-C6H6)(eta4-C6H8)] 6 and [Os4(mu-H)2(CO)8(eta6-C6H6)(eta4-C6H8)] 7. Structural analyses of 4 and 7 by single-crystal X-ray diffraction have shown that the C6H8 ligand is bonded through two alkene bonds and that the benzene ligand in 7 is co-ordinated in an eta6 fashion. In each case the ligands are bonded to single osmium atoms only. Compound 5 was also found to react with Me3NO in CH2Cl2 in the presence of benzene yielding [Os4(CO)8(eta6-C6H6)2] 8, whilst with either toluene or mesitylene it undergoes arene displacement to produce [Os4(mu-H)2(CO)10(eta6-C6H5Me)] 9 or [Os4(mu-H)2(CO)10(eta6-C6H4Me2-1,3)] 10 respectively
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