An Innovative Sb^III-W^VI-Cotemplated Antimonotungstate with Potential in Sensing Paroxetine Electrochemically

Advances in polyoxometalate (POM) self-assembly chemistry are always accompanied by new developments in molecular blocks. The exploration and discovery of uncommon building blocks offer great possibilities for generating unprecedented POM clusters. An intriguing Sb^III-W^VI-cotemplated antimonotungstate [H₂N(CH₃)₂]₁₁Na[SbW₉O₃₃]Er₂(H₂O)₂Sb₂[SbW^VIW₁₅O₅₇]·22H₂O (1) was synthesized, which comprises a classical trivacant Keggin [SbW₉O₃₃]^9- ({SbW₉}) fragment and an unclassical lacunary Dawson-like [SbW^VIW₁₅O₅₇]^15- ({SbW^VIW₁₅}) subunit. Notably, the Dawson-like {SbW^VIW₁₅} subunit is the first example of a [SbO₃]^3- and [W^VIO₆]^6- mixed-heteroatom-directing POM segment. Hexacoordinated [W^VIO₆]^6- can not only serve as the heteroatom function but its additional oxygen sites can also link to lanthanide, main-group metal, and transition-metal centers to form the innovative structure. {SbW^VIW₁₅} and {SbW₉} subunits are joined by the heterometallic [Er₂(H₂O)₂Sb₂O₁₇]^22- cluster to give rise to an asymmetric sandwich-type architecture. To further realize its potential application in electrochemical sensing, a conductive 1@rGO composite was obtained by the electrochemical deposition of 1 with graphene oxide (GO). Using a 1@rGO-modified glassy carbon electrode as the working electrode, an electrochemical biosensor for detecting the antidepressant drug paroxetine (PRX) was successfully constructed. This work can provide a viable strategy for synthesizing mixed-heteroatom-directing POMs and demonstrates the application of POM-based materials for the electrochemical detection of drug molecules.