Double Trigonal Pyramidal {SeO} Groups Bridged 2-Picolinic Acid Modified Cerium-Inlaid Polyoxometalate Including Mixed Selenotungstate Subunits for Electrochemically Sensing Ochratoxin A.

An organic-inorganic hybrid trigonal pyramidal {SeO} group, bridged cerium-inlaid polyoxometalate (POM) Na[SeCe(HO)W(HPIC)O][B-β-SeWO][SeWO]·60HO () (HPIC = 2-picolinic acid), containing two disparate selenotungstate (ST) building blocks was synthesized by a one-step assembly strategy, which is established by two asymmetric sandwich-type {[Ce(HO)W(HPIC)O][B-β-SeWO][SeWO]} moieties joined by double trigonal pyramidal {SeO} groups. Its outstanding structural trait is that it contains two types of ST building blocks, Keggin-type [B-β-SeWO] and Dawson-like [SeWO], which are extremely rare in ST chemistry. Remarkably, [SeWO] is first obtained in lanthanide-inlaid STs. Furthermore, @PPy conductive film (PPy = polypyrrole) was prepared by electrochemical polymerization and served as the electrode material, and then nano-gold particles (NGPs) were deposited on the surface of @PPy conductive film by an electrochemical deposition method in order to immobilize the aptamer of ochratoxin A. With the help of exonuclease I (EN I), the oxidation peak of the metalized Ag works as the detection signal to achieve the detection of ochratoxin A (OTXA). This study offers an available approach for creating organic-inorganic hybrid heteroatom-bridged lanthanide-inlaid POMs and reveals the likelihood of extending heteroatom-bridged lanthanide-inlaid POMs into electrochemical biosensing applications.