Tricarboxylic-Ligand-Decorated Lanthanoid-Inserted Heteropolyoxometalates Built by Mixed-Heteroatom-Directing Polyoxotungstate Units: Syntheses, Structures, and Electrochemical Sensing for 17β-Estradiol.

Organic-inorganic hybrid metal-oxide clusters have been pursued for many years, benefiting from their abundant structures and prominent performances. Upon our exploration, a family of unusual mixed-heteroatom (Sb, P)-directing lanthanoid (Ln)-inserted heteropolyoxotungstates (Ln-HPOTs), [(CH)NH]NaH[Ln(HP)W(HO)(Hptca)O][SbWO]·27HO [Ln = Ce (), La (), Pr ()], functionalized by 1,2,3-propanetricarboxylic acid (Hptca) was achieved. The intriguing trimeric [Ln(HP)W(HO)(Hptca)O][SbWO] polyanion was established by two trivacant [B-α-SbWO] segments mounted on both sides and one rare [HPWO] segment at the bottom, which are bridged via an organic-inorganic hybrid [WLn(HO)O(Hptca)] central moiety. Such Ln-HPOTs involving dual-heteroatom-directing mixed building blocks, and even simultaneously modified by tricarboxylic ligands, are rather unseen in polyoxometalate chemistry. Moreover, the detection of 17β-estradiol through a -based electrochemical biosensor has been explored, demonstrating a low detection limit (7.08 × 10 M) and considerable stability.