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Dinuclear ruthenium sawhorse-type complexes containing bridging ligands with ferrocenyl substituents in endo/endo, endo/exo and exo/exo orientations

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

The dinuclear ruthenium complexes Ru2(CO)4(OOCC5H4FeC5H5)2L2 (L = NC5H5: 1, L = PPh3: 2) have been synthesized from Ru3(CO)12, ferrocene carboxylic acid and pyridine or triphenylphosphine, respectively. The single-crystal X-ray structure analysis 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 derivative NC5H4OOCC5H4FeC5H5 (4-ferrocenoyl pyridine) (3) as axial ligand, the complex Ru2(CO)4(OOCC5H4FeC5H5)2(NC5H4OOCC5H4FeC5H5)2 (4) was obtained, the single crystal X-ray structure analysis 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 transoïd with respect to each other; this complex is accessible from Ru3(CO)12, ferrocenamide and triphenylphosphine.

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Synthesis and characterization of tetrahedral Ru3O clusters with intrinsic framework chirality: a chiral probe of the intact cluster catalysis concept. [Erratum to document cited in CA144:088385]

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)]

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Synthesis and Characterization of Tetrahedral Ru3O Clusters with Intrinsic Framework Chirality: A Chiral Probe of the Intact Cluster Catalysis Concept

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)]

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Framework fluxionality of organometallic oxides: Synthesis, crystal structure, EXAFS, and DFT studies on [{Ru(eta(6)-arene)}(4)Mo4O16] complexes

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.

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Dinuclear manganese complexes containing 1,4-dimethyl-1,4,7-triazacyclononane ligands as well as carboxylato and oxo bridges

2006, Romakh, Vladimir B., Therrien, Bruno, Karmazin-Brelot, Lydia, Labat, Gael, Stoeckli-Evans, Helen, Shul’pin, Georgiy B., Süss-Fink, Georg

The reaction of 1,4-dimethyl-1,4,7-triazacyclononane (L-Me2) with MnCl2 • 4H2O in acetonitrile gives, in the presence of sodium formate, hydrogen peroxide, triethylamine and KPF6, the dinuclear Mn(III)–Mn(IV) complex cation [(L-Me2)2Mn2 (O) 2 (OOCH)]2+ (1) which crystallises as the hexafluorophosphate salt.The analogous reaction with sodium benzoate, however, yields the dinuclear Mn(III)–Mn(III) complex cation [(L-Me2)2Mn2 (O)(OOCC6H5)2]2+ (2), isolated also as the hexafluorophosphate salt.In the case of sodium acetate, both cations, the Mn(III)–Mn(IV) complex [(L-Me2)2Mn2 (O) 2 (OOCCH3)]2+ (3) and the known Mn(III)–Mn(III) complex [(L-Me2)2Mn2 (O)(OOCCH3)2]2+ (4) are available, depending upon the molar ratio.The single-crystal X-ray structure analyses show for the green crystals of [1][PF6]1.5 [Cl]0.5 • 1.5 H2O and [3][PF6]2 • (CH3)2CO, a Mn–Mn distance of 2.620(2) and 2.628(4) Å, respectively, while for the red-violet crystal of [4][PF6]2, a Mn–Mn distance of 3.1416(8) Å is observed.All four compounds show catalytic activity for the oxidation of isopropanol with hydrogen peroxide in water and in acetonitrile to give acetone in the presence of oxalic or ascorbic acid as co-catalysts.

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Dinuclear ruthenium sawhorse-type complexes containing bridging ligands with ferrocenyl substituents in endo/endo, endo/exo and exo/exo orientations

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)]

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Mono and oligonuclear vanadium complexes as catalysts for alkane oxidation : synthesis, molecular structure, and catalytic potential

2004-01-30, Süss-Fink, Georg, Gonzalez Cuervo, Laura, Therrien, Bruno, Stoeckli-Evans, Helen, Shul’pin, Georgiy B.

A series of mono- and oligonuclear vanadium(V) and vanadium(IV) complexes containing various chelating N,O-, N3-, and O2-ligands have been prepared. The biphasic reaction of an aqueous solution of ammonium vanadate and a dichloromethane solution of hexamethylphosphoramide (hmpa) and pyrazine-2-carboxylic acid (pcaH) or pyrazine-2,5-dicarboxylic acid (pdcaH2) or pyridine-2,5-dicarboxylic acid (pycaH2) yields yellow crystals of [VO2 (pca)(hmpa)] (1), [(VO2)2(pdca)(hmpa)2] (2), and [VO2(pycaH)(hmpa)] (3), respectively. The single-crystal X-ray structure analyses reveal 1 and 3 to be mononuclear vanadium(V) complexes, in which a VO2 unit coordinates to one nitrogen and one oxygen atom of a pca or pycaH chelating ligand, and 2 to be a dinuclear vanadium(V) complex, in which two VO2 units are coordinated through one nitrogen and one oxygen atom of a pdca bridging ligand; in the three complexes the vanadium atoms also coordinate to the oxygen atom of a hmpa ligand. The reaction of N,N,N′,N′-tetrakis(2-benzimidazolylmethyl)-2-hydroxo-1,3-diaminopropane (hptbH) and VOSO4 in methanol gives the cationic complex [(VO)4(hptb) 2(μ-O)]4+ (4), which can be crystallized as the perchlorate salt. In this tetranuclear complex, two dinuclear vanadium(IV) units are held together by a μ-oxo bridge. The known complex [VOCl2 (tmtacn)] (5) was synthesized from the reaction of 1,4,7-trimethyl-1,4,7-triazacyclononane (tmtacn) and VCl3 in acetonitrile; the reaction of tetrabutylammonium vanadate with pyro-cathecol (catH2) in acetonitrile gives the known anionic complex [V(cat)3]− (6), in which the vanadium(V) center is bonded to three cat chelating ligands through the oxygen atoms, obtained as the tetrabutylammonium salt. All compounds synthesized are highly efficient oxidation catalysts for the reaction of cyclohexane with air and hydrogen peroxide in the presence of four equivalents of pcaH per vanadium, although the catalytic activity of the complexes containing bulky chelating ligands 4 and 5 is somewhat lower in the initial period of the reaction. During this period the active species are formed from the complexes and final turnover numbers are high. The catecholate ligands of complex 6 may reduce from V(V) to V(IV) in the beginning of the process, thus providing very high initial oxidation rates.

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Dinuclear iron, ruthenium and cobalt complexes containing 1,4-dimethyl-1,4,7-triazacyclononane ligands as well as carboxylato and oxo or hydroxo bridges

2006, Romakh, Vladimir B., Therrien, Bruno, Labat, Gael, Stoeckli-Evans, Helen, Shul’pin, Georgiy B., Süss-Fink, Georg

The reaction of 1,4-dimethyl-1,4,7-triazacyclononane (L–Me2) with FeSO4 • 7H2O in aqueous ethanol gives, in the presence of sodium carboxylates, hydrogen peroxide, sodium hydroxide and KPF6, the dinuclear Fe(III)–Fe(III) complex cations [(L–Me2)2Fe2(O)(OOCR) 2]2+ (R = H: 1, R = CH3: 2, R = C6H5: 3), which crystallise as the hexafluorophosphate salts. The corresponding reaction with RuCl3 • nH2O does not work, however, the analogous Ru(III)–Ru(III) complex [(L–Me2)2Ru2 (O)(OOCCH3)2]2+ (5) can be synthesised by reacting Ru(dmso)4Cl2 with L–Me2, HCl and air in refluxing ethanol, followed by addition of sodium acetate, the mononuclear intermediate (L–Me2)RuCl3 • H2O (4) being also isolated and characterised. The reaction of L–Me2, sodium acetate, hydrogen peroxide and triethylamine with CoCl2 • 6H2O in acetonitrile yields, however, the hydroxo-bridged Co(III)–Co(III) complex [(L–Me2)2Co2 (OH)(OOCCH3)2]3+ (6). The molecular structures of 2, 5 and 6, solved by single-crystal X-ray structure analyses of the hexafluorophosphate salts, reveal for the orange crystals of [2][PF6]2 a Fe–Fe distance of 3.104(1) Å, for the purple crystals of [5][PF6]2 a Ru–Ru distance of 3.230(1) Å, and for the violet crystals of [6][PF6]3 • (CH3)2CO a Co–Co distance of 3.358(1) Å. All six complexes show catalytic activity for the oxidation of isopropanol with hydrogen peroxide in water to give acetone in the presence of ascorbic acid as co-catalyst.

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Water-Soluble Arene Ruthenium Complexes Containing a trans-1,2-Diaminocyclohexane Ligand as Enantioselective Transfer Hydrogenation Catalysts in Aqueous Solution

2005, Canivet, Jérôme, Labat, Gael, Stoeckli-Evans, Helen, Süss-Fink, Georg

The cationic chloro complexes [(arene)Ru(H2N∩NH2)Cl]+ (1: arene = C6H6; 2: arene = p-MeC6H4iPr; 3: arene = C6Me6) have been synthesised from the corresponding arene ruthenium dichloride dimers and enantiopure (R,R or S,S) trans-1,2-diaminocyclohexane (H2N∩NH2) and isolated as the chloride salts. The compounds are all water-soluble and, in the case of the hexamethylbenzene derivative 3, the aqua complex formed upon hydrolysis [(C6Me6)Ru(H2N∩NH2)OH2]2+ (4) could be isolated as the tetrafluoroborate salt. The molecular structures of 3 and 4 have been determined by single-crystal X-ray diffraction analyses of [(C6Me6)Ru(H2N∩NH2)Cl]Cl and [(C6Me6)Ru(H2N∩NH2)OH2][BF4]2. Treatment of [Ru2 (arene) 2Cl4] with the monotosylated trans-1,2-diaminocyclohexane derivative (TsHN∩NH2) does not yield the expected cationic complexes, analogous to 1-3 but the neutral deprotonated complexes [(arene)Ru(TsN∩NH2)Cl] (5: arene = C6H6; 6: arene = p-MeC6H4iPr; 7: arene = C6Me6; 8: arene = C6H5COOMe). Hydrolysis of the chloro complex 7 in aqueous solution gave, upon precipitation of silver chloride, the corresponding monocationic aqua complex [(C6Me6)Ru(TsHN∩NH2)(OH2)]+ (9) which was isolated and characterised as its tetrafluoroborate salt. The enantiopure complexes 1-9 have been employed as catalysts for the transfer hydrogenation of acetophenone in aqueous solution using sodium formate and water as a hydrogen source. The best results were obtained (60 °C) with 7, giving a catalytic turnover frequency of 43 h-1 and an enantiomeric excess of 93 %.

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Di-mu-acetato-kappa O-4 : O '-tetracarbonylbis(pyridyl-2-yl-kappa N-amine)diruthenium(I)(Ru-Ru)

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.