Reversible capping/uncapping of phosphorous-centered Keggin-type polyoxoniobate clusters†
Abstract
Caps in α-Keggin-type polyoxometalates [PM2Nb12O40]9− (M: NbO or V
O) can be removed in basic condition to produce uncapped [PNb12O40]15−. Transmetalation or capping occurs from the reaction of [PNb14O42]9− or [PNb12O40]15− with either Sb2O3 or V2O5 to form [PSb2Nb12O40]9− or [PV2Nb12O42]9−, respectively.