Fine tuning of the properties of organically modified heteropolymetalates

Keggin-type organically modified oxopolymetalates of formula [R](4)[SiW11O40(SiR')(2)], (R=Bu(4)N(+), R' = -C2H5, -C10H21, -CH=CH2, -CH2CH=CH2, -OH, -C6H5, -C10H7, -C6H4NH2 (o, p), -C(6)H(4)NMe(2) (p), -C6H4CH=CH2, -C6H4CF3, -C6H4CH=CHC6H5) were synthesized. The oxide core presented reversible redox properties which were tuned by the choice of the organic modifier. Parallel variations of the W-183 NMR chemical shifts were measured and both effects might be related to the electronic donor-acceptor properties of the organic radical. The magnitudes of these effects are compared with those coming from the electrolyte itself.