Organofunctionalised borotungstate Keggin polyoxometalates, (nBu4N)3H[HBW11O39(P(O)Ph)2] (PBW11), (nBu4N)3H[HBW11O39(As(O)Ph)2] (AsBW11), and (nBu4N)4[HBW11O39(PhSiOSiPh)] (SiBW11), were synthesized and structurally characterized. Cyclic voltammetry showed that the electronic properties of the clusters are dependent on the...