Two Innovative Fumaric Acid Bridging Lanthanide-Encapsulated Hexameric Selenotungstates Containing Mixed Building Units and Electrochemical Performance for Detecting Mycotoxin
Xiaodan Jia, Jun Jiang, Lulu Liu, Lina Meng, Lijuan Chen, Junwei Zhao
Abstract
Two particular fumaric acid bridging lanthanide-encapsulated selenotungstates [H2N(CH3)2]16Na8[Ln3(H2O)7]2 [W4O8(C4H2O4) (C4H3O4)]2[SeW6O25]2[B-α-SeW9O33]4·46H2O [Ln = Ce3+ (1), La3+ (2)] were acquired by the deliberately designed step-by-step synthetic strategy, which are composed of four trilacunary Keggin [B-α-SeW9O33]8– and two original [SeW6O25]10– building units together with one fumaric acid bridging heterometallic [Ln3(H2O)7]2[W4O8(C4H2O4) (C4H3O4)]228+ 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.