Stoeckli-Evans, Helen

2004, Dorta, Reto, Süss-Fink, Georg, Stoeckli-Evans, Helen

The structure of the title compound, [Ru-2(C2H3O2)(2)(C5H6N2)(2)(CO)(4)], consists of a 'sawhorse' diruthenium complex with two acetate bridges and two 2-aminopyridine ligands in the axial positions, coordinating via the pyridine N atoms. A double-stranded hydrogen-bonded chain is formed via intra- and intermolecular hydrogen bonds involving the amine groups, one O atom of both acetate groups and two carbonyl O atoms.

1999, Ferrand, Vincent, Süss-Fink, Georg, Neels, Antonia, Stoeckli-Evans, Helen

The tetrahedral cluster anion [Ru3Ir(CO)(13)](-) (1) reacts with internal alkynes RC=CR' to afford the alkyne derivatives [Ru3Ir(CO)(11) (RCCR')](-) (2: R = R' = Ph; 3: R = R' = Et; 4: R = Ph; R' = Me; 5: R = R' = Me) which have a butterfly arrangement of the Ru,Ir skeleton in which the alkyne is coordinated in mu(4)-eta(2) fashion. Under CO pressure they undergo fragmentation to give the trinuclear cluster anions [Ru2Ir(CO)(9)(RCCR')](-) (6: R = R' = Ph; 7: R = R' = Et; 8: R = Ph; R' = Me; 9: R = R' = Me), in which the alkyne ligand is coordinated in a mu(3)-eta(2) parallel fashion. Protonation of these trinuclear anions leads to the formation of the corresponding neutral hydride clusters [HRu2Ir(Co)(9)(RC=CR')] (10: R = R' = Ph; 11: R = R' = Et; 12: R = Ph; R' = Me; 13: R = R' = Me). The protonation of the butterfly anions 2 and 3, however, gives rise to the formation of the neutral tetrahedral clusters [HRu3Ir(CO)(11)(RCCR')] (14: R = R' = Ph and 15: R = R' = Et), respectively. The analogous clusters [HRu3Ir(CO)(11)(PhCCCH3)] (16) and [HRu3Ir(CO)(11)(CH3CCCH3)] (17) are only accessible from the reaction of the neutral cluster [HRu3Ir(CO)(13)] with the corresponding alkynes. The complexes 2, 4, 5, 6, 10, 12 and 15 are characterised by Xray structure analysis.

1999, Neels, Antonia, Stoeckli-Evans, Helen, Plasseraud, Laurent, Fidalgo, Eva Garcia, Süss-Fink, Georg

The homologous title molecules, [Ru2Br4(C10H14)(2)]. C6H6, (1), and [Ru2I4(C10H14)(2)]. C7H8, (2), consist of arene-ruthenium moieties [Ru-to-ring distances of 1.655 (2) Angstrom in (1) and 1.673(3) Angstrom in (2)] with a terminal halogen ligand and [Ru-Br 2.548 (1) Angstrom in (1) and Ru-I 2.726(1) Angstrom in (2)], held together by two symmetrical halogen bridges [Ru-Br 2.575(1) Angstrom in (1) and Ru-I 2.736(1) Angstrom in (2)]. The arene rings are planar and parallel to each other, and the terminal halogen ligands are coordinated to rurthenium trans with respect to each other. Both molecules possess C-i symmetry.

2002, Fidalgo, Eva Garcia, Neels, Antonia, Stoeckli-Evans, Helen, Süss-Fink, Georg

The hydrothermal reaction of Na2MoO4 with pyridine in water at pH 5 and 130 degreesC gives the octamolybdate anion [Mo-8(VI) O-26(OH)](5-) (1) which crystallises as the pyridinium salt; its molecular structure derives from that of the parent alpha-octamolybdate anion [Mo-8(VI) O-26](4-) by opening two molybdenum-oxygen bond and adding a hydroxo bridge. The same reaction in the presence of NaAsO2 yields the mixed-valence arsenatomolybdate [Has(III)As(V)Mo(V)Mo(8)(VI)O(34)](6-) (2) which is also isolated as the pyridinium salt. Anion 2 has a lacunary structure like an open basket, which derives from the famous alpha-Keggin structure by removing three edge-sharing MoO6 octahedra and by capping a trioxygen face of three remaning MoO6 octahedra with an AsH group. Reaction of 2 with Co2+ leads to the anion [(HAsAsMoMo8VI)-As-III-Mo-V-Mo-V O-34 {Co(C5H5N)(2)(H2O)(3)}](4-) (3) which crystallises as a double pyridinium salt together with anion 2. The structure of 3 derives from that of 2 by attaching a Co(C5H5N)(2)(H2O)(3) fragment to a terminal oxo ligand. Reaction of 2 with hydrogen peroxide produces the fully oxydised alpha-Keggin anion [(AsMo12O40)-Mo-V-O-VI](3-) (4) which was found to crystallise as the tetrabutylammonium salt surprisingly with three independent molecules in the unit cell, two of them showing a remarkable disorder. (C) 2002 Elsevier Science Ltd. All rights reserved.

1999, Plasseraud, Laurent, Stoeckli-Evans, Helen, Süss-Fink, Georg

The title complex was obtained by reaction of [(eta(6)-p-Pr'C6H4Me)(4)Ru4Mo4O16] with methanol in the presence of p-hydroquinone. It contains an Mo2Ru2O2(OMe)(4) core consisting of two Mo2RuO(OMe)(3) half-cubes fused together to form a choir-like structure. (C) 1999 Elsevier Science S.A. All rights reserved.

1998, Dorta, Reto, Stoeckli-Evans, Helen, Bodensieck, Ulf, Süss-Fink, Georg

Melamine, C3N3(NH2)(3), was found to react with [Ru-3(CO)(12)] to give, with N-H activation, the monometallated derivative [Ru-3(mu(2)-H)(CO)(9){mu(3),eta(2)-NHC3N3(NH2)(2)}] (1) and the two isomeric bimetallated derivatives cis-[{Ru-3(mu-H)(CO)(9)}(2){mu(3),eta(2) : mu(3),eta(2) - NHC3N3(NH2)}] (cis-2) and trans-[{Ru-3(mu-H)(CO)(9)}(2){mu(3),eta(2) : mu(3),eta(2)-NHC3N3(NH2)}] (trans-2). The molecular structures of 1, cis-2 and trans-2 have been determined by single-crystal X-ray crystallography. (C) 1998 Elsevier Science S.A.

2000, Süss-Fink, Georg, Plasseraud, Laurent, Maisse-Francois, Aline, Stoeckli-Evans, Helen, Berke, Heinz, Fox, Thomas, Gautier, Régis, Saillard, Jean-Yves

A low-temperature H-1-NMR study suggests the tetranuclear cluster dication [H6Ru4(C6H6)(4)](2+) (1) to contain an H-2 ligand that undergoes, upon warming of the solution, an intramolecular exchange with the four hydride ligands at the Ru-4 framework. Whereas two of the three NMR signals at - 120 degrees C in the hydride region show T-1 values in the range 200-300 ms, the least deshielded resonance at delta = - 17.33 ppm exhibits a T-1 value of only 34 ms, characteristic of an H-2 ligand. a re-examination of the single-crystal X-ray structure analysis of the chloride salt of 1 supports this interpretation by a short distance of 1.14(0.15) Angstrom between two hydrogen atoms coordinated as a PI-PI ligand in a side-on fashion to one of the triangular faces of the Ru-4 tetrahedron. The distance between one of the two hydrogen atoms of the H-2 ligand and one of the four hydride ligands is also very short [1.33(0.15) Angstrom], suggesting an additional H-2... H interaction. The presence of this H-3, unit over one of the three Ru-3 faces in 1 may explain the deformation of the Ru-4 skeleton from the expected tetrahedral symmetry. Density functional theory (DFT) calculations on 1 indicate a very soft potential energy surface associated with the respective displacement of the three interacting cofacial hydrogen atoms. In accordance with these results, the cluster dication 1 tends to loose molecular hydrogen to form the cluster dication [H4Ru4(C6H6)(4)](2+) (2). The equilibrium between 1 and 2 can be used for catalytic hydrogenation reactions. (C) 2000 Elsevier Science S.A. All rights reserved.

1999, Süss-Fink, Georg, Haak, Susanne, Ferrand, Vincent, Neels, Antonia, Stoeckli-Evans, Helen

The reaction of the mixed-metal carbonyl cluster anion [H2Ru3Ir(CO)(12)](-) with PPh3, PMe3, P(OPh)(3), AsPh3 or SbPh3 leads to the mono-substituted derivatives [H2Ru3Ir(CO)(11)L](-) (L = PPh3 1, L = PMe3 2, L = P(OPh)(3) 3, L = AsPh3 4, L = SbPh3 5). Protonation of the anions 1-5 gives the neutral trihydrido derivatives H3Ru3Ir(CO)(11)L (L = PPh3 6, L = PMe3 7, L = P(OPh)(3) 8, L = AsPh3 9, L = SbPh3 10). All new tetranuclear clusters invariably show a tetrahedral arrangement of the Ru3Ir skeleton, as predicted for 60 e systems. The ligand L is coordinated to one of the ruthenium atoms, except in the case of L = PMe3 where two substitution isomers are observed. While the anionic isomers [H2Ru3Ir(CO)(11)(PMe3)](-) (2) could not be separated, the corresponding neutral isomers H3Ru3Ir(CO)(11)(PMe3) (7) could be resolved by thin-layer chromatography. In isomer 7a, the phosphine ligand is coordinated to one of the ruthenium atoms, whereas in isomer 7b the PMe3 ligand is bonded to the iridium atom. The molecular structures of 1, 7b, 8 and 9 were confirmed by a single-crystal X-ray structure analysis. (C) 1999 Elsevier Science S.A. All rights reserved.

1997, Ferrand, Vincent, Merzweiler, Kurt, Rheinwald, Gerd, Stoeckli-Evans, Helen, Süss-Fink, Georg

The electron-deficient cluster (mu(2)-H)Ru-3(CO)(9)[mu(3)-NS(O)MePh] (1) reacts with the terminal alkyne PhCH2C=CH to give the vinyl complex Ru-3(mu(2)-CO)(2)(CO)(6)[mu(3)-NS(O)MePh](mu(2)-eta(1),eta(2)-PhCH2C=CH2 ) (2). The analogous reaction with internal alkynes (RC=CR') affords the clusters Ru-3(mu(2)-CO)(CO)(7)[mu(3)-NS(O)MePh](mu(3)-eta(1),eta(2)-RC=CHR') (3: R = R' = Pr "; 4: R = Ph; R' = Bu ") in which the vinyl ligand has opened a Ru-Ru bond upon coordination the Ru-3 framework. In the case of diphenylacetylene, reaction with two equivalents of the alkyne, yields the vinyl-alkyne cluster (mu(2)-H)Ru-3(CO)(6)(mu(2)-eta(1),eta(2)-PhC=CHPh)(mu(3)-eta(1),eta(2)-P hC=CPh)[mu(3)-eta(1),eta(2)-NS(O)Me(C6H4)] (5) with ortho-metallation of the phenyl substituent of the sulfoximido cap. (C) 1997 Elsevier Science S.A.