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 SiW11O398– heteropolyoxometalate.