Two Innovative Fumaric Acid Bridging Lanthanide-Encapsulated Hexameric Selenotungstates Containing Mixed Building Units and Electrochemical Performance for Detecting Mycotoxin.

Two particular fumaric acid bridging lanthanide-encapsulated selenotungstates [H 2 N(CH 3 ) 2 ] 16 Na 8 [Ln 3 (H 2 O) 7 ] 2 [W 4 O 8 (C 4 H 2 O 4 ) (C 4 H 3 O 4 )] 2 [SeW 6 O 25 ] 2 [B-α-SeW 9 O 33 ] 4 ·46H 2 O [Ln = Ce 3+ ( 1 ), La 3+ ( 2 )] were acquired by the deliberately designed step-by-step synthetic strategy, which are composed of four trilacunary Keggin [B-α-SeW 9 O 33 ] 8- and two original [SeW 6 O 25 ] 10- building units together with one fumaric acid bridging heterometallic [Ln 3 (H 2 O) 7 ] 2 [W 4 O 8 (C 4 H 2 O 4 ) (C 4 H 3 O 4 )] 2 28+ entity. Particularly, this heterometallic cluster contains four fumaric acid ligands, which play two different roles: one works as the pendant decorating the cluster and the other acts as the linker connecting the whole structure. In addition, the 1@DDA hybrid material was produced through the cation exchange of 1 and dimethyl distearylammonium chloride (DDA·Cl) and its beehive-shaped film of 1@DDA was prepared by the breath figure method, which can be further used to establish an electrochemical biosensor for detecting a kind of mycotoxin-ochratoxin A (OX-A). The 1@DDA beehive-shaped film-based electrochemical biosensor exhibits good reproducibility and specific sensing toward OX-A with a low detection limit of 29.26 pM. These results highlight the huge feasibility of long-chain flexible ligands in building lanthanide-encapsulated selenotungstates with structural complexity and further demonstrate great electrochemical application potentiality of polyoxometalate-involved materials in bioanalysis, tumor diagnosis, and iatrology.