Browsing by Subject "ORGANOSILYL DERIVATIVES"

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    Rational Synthesis and Characterization of the Mixed-Metal Organometallic Polyoxometalates [Cp*MoxW6-xO18]- (x=0, 1, 5, 6)
    (AMER CHEMICAL SOC) Taban-Çaliskan, G; Fernandes, DM; Daran, JC; Agustin, D; Demirhan, F; Poli, R
    The reaction between the oxometallic complexes Cp*2M2O5 and Na2M'O-4 (M, M' = Mo, W) in a 1:10 molar ratio in an acidic aqueous medium constitutes a mild and selective entry into the anionic Lindqvist-type hexametallic organometallic mixed oxides [Cp*MoxW6-xO18](-) [x = 6 (1), 5 (2), 1 (3), 0 (4)]. All of these compounds have been isolated as salts of nBu(4)N(+) (a), nBu(4)P(+) (b), and Ph4P+ (c) cations and two of them (1 and 3) also with the n-butylpyridinium (nBuPyr(+), d) cation. The compounds have been characterized by elemental analyses, thermogravimetric analyses, electrospray mass spectrometry, and IR spectroscopy. The molecular identity and geometry of compounds 1c, 2a, and 2c have been confirmed by single-crystal X-ray diffraction. Density functional theory calculations on models obtained by replacing Cp* with Cp (I-IV) have provided information on the assignment of the terminal M=O and bridging M-O-M vibrations.
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    Rational, Facile Synthesis and Characterization of the Neutral Mixed-Metal Organometallic Oxides Cp2*MoxW6-xO17 (Cp* = C5Me5, x=0, 2, 4, 6)
    (WILEY-V C H VERLAG GMBH) Taban-Çaliskan, G; Agustin, D; Demirhan, F; Vendier, L; Poli, R
    The reaction of the bis(pentamethylcyclopentadienyl)pentaoxidodimetal complexes Cp*2M2O5 with four equivalents of Na2M'O-4 (M, M' = Mo, W) in acidic aqueous medium constitutes a soft and selective entry into neutral Lindqvist-type organometallic mixed-metal oxides Cp*2MoxW6-xO17 [x = 6 (1), 4 (2), 2 (3), 0 (4)]. The identity of the complexes is demonstrated by elemental analyses, thermogravimetric analyses and infrared spectroscopy. Thermal degradation of 1-4 up to above 500 degrees C leads to Mox/6W1-X/6O3. The molecular identity and geometry of compound 2 is further confirmed by a fit of the powder X-ray diffraction pattern with a model obtained from previously reported single-crystal X-ray structures of I and 4, with which 2 is isomorphous. DFT calculations on models obtained by replacing Cp* with Cp (I-IV) validate the structural assignments and assist in the assignment of the M,M'-O vibrations. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)