Stoeckli-Evans, Helen

2006, Vieille-Petit, Ludovic, Süss-Fink, Georg, Therrien, Bruno, Ward, Thomas R., Stoeckli-Evans, Helen, Labat, Gaeel, Karmazin-Brelot, Lydia, Neels, Antonia, Buergi, Thomas, Finke, Richard G., Hagen, Collin M.

On page 6112, Figure 9 was missing and Figure 11 appeared twice. The correct Figure 9 is given. [on SciFinder(R)]

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.

2002, Thomas, Christophe M., Mafua, Roger, Therrien, Bruno, Rusanov, Eduard, Stoeckli-Evans, Helen, Süss-Fink, Georg

The new diphosphine ligands Ph2PC6H4C(O)X(CH2)2OC(O)C6H4PPh2 (X = NH; X = NPh; X = O) and Ph2PC6H4C(O)O(CH2)2O(CH2)2OC (O)C6H4PPh2 (I) as well as the monophosphine ligand Ph2PC6H4C(O)X(CH2)2OH (II) have been prepd. from 2-diphenylphosphinobenzoic acid and the corresponding amino alcs. or diols. Coordination of the diphosphine ligands to rhodium, iridium, and platinum resulted in the formation of the square-planar complexes. In all complexes, the diphosphine ligands are trans coordinated to the metal center, thanks to the large spacer groups, which allow the two phosphorus atoms to occupy opposite positions in the square-planar coordination geometry. The trans coordination is demonstrated unambiguously by the single-crystal X-ray structure anal. of on of these complexes. In the case of the diphosphine ligand I, the spacer group is so large that dinuclear complexes with ligand I in bridging positions are formed, maintaining the trans coordination of the P atoms on each metal center, as shown by the crystal structure anal. of another complex. The monophosphine ligand II reacts with [{Ir(cod)Cl}2] (III) (cod = cyclooctadiene) to give the simple deriv. [Ir(cod)Cl] which is converted into the carbonyl complex [Ir(CO)2Cl] with carbon monoxide. The crystal structure anal. of III also reveals a square-planar coordination geometry in which the phosphine ligand occupies a position cis with respect to the chloro ligand. Some of these diphosphine ligands have been tested as cocatalysts in combination with the catalyst precursors [{Rh(CO)2Cl}2] and [{Ir(cod)Cl}2] or [H2IrCl6] for the carbonylation of methanol at 170°C and 22 bar CO. The best results (TON 800 after 15 min) are obtained for the combination X = NPh/[{Rh(CO)2Cl}2]. After the catalytic reaction, one complex is identified in the reaction mixt. and can be isolated; it is active for further runs without loss of catalytic activity. [on SciFinder(R)]

2002, Laly, Myriam, Fidalgo, Eva Garcia, Stoeckli-Evans, Helen, Süss-Fink, Georg

The heteropolyoxometalate [(HAsAsMoMo8O34)-As-III-Mo-V-Mo-V-O-VI](6-) reacts in aqueous solution with an excess of sodium metaarsenite to give a new arsenomolybdate [(As5Mo4O20)-Mo-III-O-VI(OCH3)](2-) which crystallize as the tetrabutylammonium salt. The single-crystal X-ray structure analysis reveals a heteropolyoxometalate anion containing an unusual chain of five arsenic atoms linked to each other by bridging oxygen atoms. (C) 2002 Elsevier Science B.V. All rights reserved.

2006, Auzias, Mathieu, Therrien, Bruno, Labat, Gael, Stoeckli-Evans, Helen, Süss-Fink, Georg

The dinuclear Ru complexes Ru2(CO)4(OOCC5H4FeC5H5)2L2 (L = py: 1, L = PPh3: 2) were synthesized from Ru3(CO)12, ferrocene carboxylic acid and pyridine or PPh3, resp. The single-crystal x-ray structure anal. reveals for 1 and 2 a Ru2(CO)4 sawhorse backbone with the two ferrocenyl substituents of the two carboxylato bridges being endo/exo with respect to each other in the solid state. With the new pyridine deriv. NC5H4OOCC5H4FeC5H5-4 (4-ferrocenoyloxypyridine) (3) as axial ligand, the complex Ru2(CO)4(OOCC5H4FeC5H5)2(NC5H4OOCC5H4FeC5H5-4)2 (4) was obtained, the single crystal x-ray structure anal. showing an exo/exo orientation of the two carboxylato bridges in the solid state. The endo/endo orientation is found in the solid-state structure of Ru2(CO)4(HNOCC5H4FeC5H5)2(PPh3)2 (5), the two OCNH bridges being transoid with respect to each other; this complex is accessible from Ru3(CO)12, ferrocenamide and PPh3. [on SciFinder(R)]

2004, Laurencin, Danielle, Fidalgo, Eva Garcia, Villanneau, Richard, Villain, Françoise, Herson, Patrick, Pacifico, Jessica, Stoeckli-Evans, Helen, Benard, Marc, Rohmer, Marie-Madeleine, Süss-Fink, Georg, Proust, Anna

Reactions of the molybdates Na2MoO4.2H(2)O and (nBu(4)N)(2)[Mo2O7] with [{Ru(arene)Cl-2}(2)] (arene = C6H5CH3, 1,3,5-C6H3(CH3)(3), 1,2,4,5-C6H2(CH3)(4)) in water or organic solvents led to formation of the triple-cubane organometallic oxides [{Ru(eta(6)- arene)}(4)Mo4O16], whose crystal and molecular structures were determined. Refluxing triple cubane [{Ru(eta(6)-C6H5CH3)}(4)Mo4O16] in methanol caused partial isomerization to the windmill form. The two isomers of [{Ru(eta(6)-C6H5CH3)}(4)Mo4O16] were characterized by Raman and Mo K-edge X-ray absorption spectroscopy (XAS), both in the solid-state and in solution. This triple-cubane isomer was also used as a spectroscopic model to account for isomerization of the p-cymene windmill [{Ru(eta(6)-1,4-CH3C6H4CH(CH3)(2))}(4)Mo4O16] in solution. Using both Raman and XAS techniques, we were then able to determine the ratio between the windmill and triple-cubane isomers in dichloromethane and in chloroform. Density functional calculations on [{Ru(eta(6)-arene)}(4)Mo4O16] (arene=C6H6, C6H5CH3, 1,3,5-C6H3(CH3)(3), 1,4-CH3C6H4CH-(CH3)(2), C-6(CH3)(6)) suggest that the windmill form is intrinsically more stabel, provided the complexes are assumed to be isolated. Intramolecular electrostatic interactions and steric bulk induced by substituted arenes verse the energy difference between the isomers. The stability of the triple-cubane isomers should therefore be accounted for by effects of the surroundings that induce a shift in the energy balance between both forms.

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.

2005, Vieille-Petit, Ludovic, Süss-Fink, Georg, Therrien, Bruno, Ward, Thomas R., Stoeckli-Evans, Helen, Labat, Gaeel, Karmazin-Brelot, Lydia, Neels, Antonia, Buergi, Thomas, Finke, Richard G., Hagen, Collin M.

Triruthenium mixed-ligand tetrahedral oxo-capped clusters with framework chirality were prepd. by redn. of areneruthenium triaqua dications followed by capping with areneruthenium dimer as racemic mixts.; diastereomeric mixts. were prepd. using chiral ligand; the prepd. complexes hydrogenate 2-acetamidoacrylate with no ee. Reaction of ArRuCl(?-Cl)2ClRuAr and Ar1RuCl(?-Cl)2ClRuAr1 with Ag2SO4 in aq. soln. gave mixt. of [ArRu(OH2)3]2+ and [Ar1Ru(OH2)3]2+, which upon NaBH4 redn. afforded mixed-ligand binuclear complex Ar1Ru(?-H)3RuAr (4, Ar = ?6-C6Me6, Ar1 = ?6-cymene). Reaction of 4 with Ar2RuCl(?-Cl)2ClRuAr2 and H2O gave the trinuclear cluster [(ArRu)(Ar1Ru)(Ar2Ru)(?3-O)(?-H)3]+ (rac-5, Ar2 = ?6-C6H6). Diastereomeric complexes [(ArRu)(Ar1Ru)(Ar*Ru)(?3-O)(?-H)3]+ [(S,R)-7, (R,R)-7; Ar* = (R)-1-phenylethanol] were prepd. by reaction of 4 with [Ar*RuCl(?-Cl)2ClRuAr*] (6). Analogous complex [(ArRu)(Ar1Ru)(Ar3Ru)(?3-O)(?-H)3]+ (8) was prepd. as a racemic mixt. from known (S,S)-Ar3RuCl(?-Cl)2ClRuAr3 [Ar3 = Et (R)-N-acetyl-?-aminobenzeneacetate]; the complex 8 was sepd. into diastereomers by chromatog., the racemization being caused by epimerization of the chiral ?-carbon. The enantiopure diastereomeric triruthenium clusters [(ArRu)(Ar1Ru)(Ar4Ru)(?3-O)(?-H)3]+ [(S,S)-17, (R,S)-17; Ar4 = (R)-N-acetyl-?-aminobenzeneethanol isobutyrate] were finally prepd. from (S,S)-Ar4RuCl(?-Cl)2ClRuAr4 and 4. The chiral Ru3O framework was evidenced by x-ray crystallog., by CD in the UV and IR regions, and by chiral shift reagents in the NMR spectra. To bring evidence for or against the hypothesis of catalytic hydrogenation by intact trinuclear arene ruthenium clusters contg. an oxo cap, catalytic hydrogenation of Me 2-acetamidoacrylate catalyzed by complexes 13 was performed; the complexes showed low catalytic activity and no asym. induction. [on SciFinder(R)]

2003, Cabort, Amel, Michel, Armelle, Therrien, Bruno, Stoeckli-Evans, Helen, Bernauer, Klaus, Süss-Fink, Georg, Williams, Alan F., Stupka, Gilles

The coordination of 2,6-bis(3,4-dihydro-2H-pyrrol-5-yl)pyridine (L) to Ni, Ru, Fe, and Co was studied. The reaction with Ni salts gives the Ni(II) complex [Ni(L)2]2+ (1). The reaction of RuCl3 gives only the Ru(II) complex [Ru(L)2]2+ (2). In the case of Fe, both [Fe(L)2]2+ (3) and [Fe(L)2]3+ (4) were synthesized and characterized. In the case of Co, the Co(III) complex [Co(L)2]3+ (5) was obtained, even if a Co(II) salt was used. However, [Co(L)2]2+ (6) can be obtained under N. Mol. structures of 1-5 complexes were detd. by x-ray anal. of the corresponding perchlorate salts; the structure of 3 was solved for both the perchlorate and the tetrachloroferrate(III) salts. All complexes show an octahedral coordination geometry with meridional arrangement of the two tridentate ligands. The electrochem. behavior of 2, 3 and 6 was studied by cyclic voltammetry. Quasi reversible electron transfer is obsd. for the redox pairs FeIII/FeII and CoII/CoI. The reaction shows somewhat weaker reversibility for CoIII/CoII, whereas the reaction of RuIII/RuII is not reversible. The measurements suggest 2,6-bis(3,4-dihydro-2H-pyrrol-5-yl)pyridine (L) to have a higher stabilization of low-valent oxidn. states of Fe and Co than terpyridine. [on SciFinder(R)]

2002, Cherioux, Frederic, Therrien, Bruno, Stoeckli-Evans, Helen, Süss-Fink, Georg

The title compd. is obtainable from 1,3-dicyclohexylcarbodiimide and pyrazine-2-carboxylic acid in DMF in the presence of catalytic amts. of [H3Ru4(C6H6)4OH]Cl2. Crystals of the compd. are orthorhombic, space group P212121, with a 9.4745(8), b 11.9101(7), c 15.8212(10) Å; Z = 4, dc = 1.229; R = 0.028, Rw(F2) = 0.058 for 3477 reflections. The intermol. N-H...O=C H bond is responsible for the formation of infinite chains stretching along the a axis of the crystal. [on SciFinder(R)]