Tricarboxylic-Ligand-Decorated Lanthanoid-Inserted Heteropolyoxometalates Built by Mixed-Heteroatom-Directing Polyoxotungstate Units: Syntheses, Structures, and Electrochemical Sensing for 17β-Estradiol
Saisai Xie, Jun Jiang, Dan Wang, Zhigang Tang, Runfei Mi, Lijuan Chen, Junwei Zhao
Abstract
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 (SbIII, PIII)-directing lanthanoid (Ln)-inserted heteropolyoxotungstates (Ln-HPOTs), [(CH3)2NH2]2Na7H3[Ln4(HPIII)W8(H2O)12(H2ptca)2O28][SbIIIW9O33]2·27H2O [Ln = Ce3+ (1), La3+ (2), Pr3+ (3)], functionalized by 1,2,3-propanetricarboxylic acid (H3ptca) was achieved. The intriguing trimeric [Ln4(HPIII)W8(H2O)12(H2ptca)2O28][SbIIIW9O33]212– polyanion was established by two trivacant [B-α-SbIIIW9O33]9– segments mounted on both sides and one rare [HPIIIW4O18]8– segment at the bottom, which are bridged via an organic–inorganic hybrid [W4Ln4(H2O)12O10(H2ptca)2]14+ 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 1-based electrochemical biosensor has been explored, demonstrating a low detection limit (7.08 × 10–14 M) and considerable stability.