Synthesis and multispectroscopic characterization of organically modified polyoxometalates

Abstract

Organically modified ‘Keggin-type’ oxopolymetalates of general chemical formula [R]₄[SiW₁₁O₄₀(SiR″)₂], (R = H⁺, K⁺ or NR′₄⁺; R′= Me or Bu; R″= Et, CHCH₂, C₁₀H₂₁ or Ph) have been synthesised by three different procedures. Large quantities were obtained in high purity and good yield. Their structure has been established by a multispectroscopic study, elemental mass analysis, and time of flight spectrometry (²⁵²Cf). Selection rules governing the latter technique are also detailed. IR, ²⁹Si and ¹⁸³W NMR spectroscopy confirm that two organic silicon groups are bonded to the surface of the lacunar SiW₁₁O₃₉^8– heteropolyoxometalate.