New organosilyl derivatives of the Dawson polyoxometalate [α2-P2W17O61(RSi)2O]6-:: Synthesis and mass spectrometric investigation

In the field of functionalized polyoxometalates, organosilyl derivatives of polyoxotungstate constitute a special class of hybrid organic-inorganic system. The first organosilyl derivative of the monovacant Dawson heteropolyoxotungstate [alpha(2)-P2W17O61](10-) was obtained by three different methods. The use of two organosilanes as reagents enabled the preparation of the functionalized polyoxometalate [alpha(2)-P2W17O61(RSi)(2)O](6-) in good yield. Electrospray (ESI-MS) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, and W-183, P-31, and Si-29 NMR spectroscopy were used to characterize the composite systems. In several cases, ESI-MS analyses generated reduction processes which were compared to those related to [PMo11VO40](4-), the highly reducible Keggin polyoxometalate.