Rational, Facile Synthesis and Characterization of the Neutral Mixed‐Metal Organometallic Oxides Cp 2 Mo x W 6– x O 17 (Cp = C 5 Me 5 , x = 0, 2, 4, 6)

The reaction of the bis(pentamethylcyclopentadienyl)pentaoxidodimetal complexes Cp* 2 M 2 O 5 with four equivalents of Na 2 M′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* 2 Mo x W 6– x O 17 [ 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 °C leads to Mo x /6 W 1– x /6 O 3 . 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 1 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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)