Browsing by Author "Taban G."

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    Reduction of [Cp2*Mo2O5] by thioglycolic acid in an aqueous medium: Synthesis and structure of [{Cp*Mo(μ-SCH2COO)}2(μ-S)]
    (2006) Demirhan F.; Taban G.; Baya M.; Dinoi C.; Daran J.-C.; Poli R.
    Compound [Cp2*Mo2O5] reacts with thioglycolic acid, HSCH2COOH, in an acidic (CF3COOH) mixed water-methanol solvent, to yield compound [{Cp*Mo(μ-SCH 2CO2)}2(μ-S)]. During this reaction, the thioglycolic acid acts as a reducing agent, as a ligand, and provides a sulfide ion for the Mo-S-Mo bridge. The molecular structure of the product can be described as containing two four-legged piano stools that share three legs. The Mo-Mo distance of 2.792(7) Å indicates metal-metal bonding, in agreement with the compound diamagnetism. © 2005 Elsevier B.V. All rights reserved.
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    Improved syntheses of [Cp2* Mo2 O5] and [Cp2* W2 O5]: Structural characterization of Na[Cp*MoO3] · 5H2O and [Cp2* W2 O5]
    (2007) Dinoi C.; Taban G.; Sözen P.; Demirhan F.; Daran J.-C.; Poli R.
    Use of aqueous conditions and the ROOH (R = tBu or H) compounds as oxidizing agents affords a simple two-step, one-pot synthetic procedure leading to [Cp2* M2 O5] (M = Mo, W) from [M(CO)6] selectively and in high yields. The hexacarbonyl compounds are converted to Na[Cp*M(CO)3] in refluxing THF, then the mixture is diluted with water (W) or aqueous NaOH (Mo) and directly treated with 6 equiv. of ROOH. Acidification of an aqueous solution of the Na[Cp*MO3] product affords spectroscopically pure [Cp2* M2 O5] in high isolated yields (global yields from [M(CO)6], for R = tBu: Mo, 91%; W, 87%). The X-ray structures of Na[Cp*MoO3] · 5H2O and [Cp2* W2 O5] are also reported. © 2007 Elsevier B.V. All rights reserved.
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    Aqueous reduction of [Cp*2W2O5]: Characterization of the triangular clusters [Cp*3W 3O4(OH)2]2+ and [Cp* 3W3O6]+ - Comparison with molybdenum
    (Wiley-VCH Verlag, 2007) Dinoi C.; Sözen P.; Taban G.; Demir D.; Demirhan F.; Prikhodchenko P.; Gun J.; Lev O.; Daran J.-C.; Poli R.
    Zinc reduction of Cp*2W2O5 in an acidified water-methanol medium affords the green 3-electron trinuclear cluster [Cp*3W3O4(OH)2]2+, isolated and crystallographically characterized as the triflate salt, 1. Upon exposure to air, this complex is oxidized to a related 2-electron cluster, [Cp*3W3O6]+, which was crystallized and characterized in three different salts, 2-4. The 3-electron cluster exhibits a near-tetragonal frozen-glass EPR spectrum, and it shows evidence of coupling of the unpaired electron to only one of the three W atoms. The two-electron cluster is diamagnetic. An electrospray ionization MS n study revealed a stepwise expulsion of neutral [Cp*WO 2] units as the main fragmentation process. DFT calculations unveiled the intimate details of the electronic structures of these complexes and fully rationalized the structural and spectroscopic properties. © Wiley-VCH Verlag GmbH & Co. KGaA, 2007.