A double-oxalate-bridging tetra-Gd 3+ containing divacant Lindqvist dimeric isopolytungtate Na 10 [Gd 2 (C 2 O 4 )(H 2 O) 4 (OH)W 4 O 16 ] 2 •30H 2 O (Gd 4 W 8 ) was obtained based on the reaction of Na 2 WO 4 •2H 2 O, H 2 C 2 O 4 , and GdCl 3 in aqueous solution. Its dimeric polyoxoanion is established by two divacant Lindqvist [W 4 O 16 ] 8− segments c o n n e c t e d b y a r e c t a n g u l a r t e t r a -n u c l e a r i t y [Gd 4 (C 2 O 4 ) 2 (H 2 O) 8 (OH) 2 ] 6+ cluster. Notably, neighboring trinuclear10− polyoxoanions together, giving rise to an intriguing 3-D extended porous framework. The red emitter Eu 3+ ions and green emitter Tb 3+ ions are first codoped into Gd 4 W 8 to substitute Gd 3+ ions for the exploration of the energy transfer (ET) mechanism between Eu 3+ and Tb 3+ ions and the color-tunable PL property in the isopolytungtate system. The PL emission spectra and decay lifetime measurements of the Eu 3+ /Tb 3+ codoped Gd 4 W 8 system illustrate that under excitation at 370 nm, Tb 3+ ions can transfer energy to Eu 3+ ions. When the molar concentration of Tb 3+ ions is fixed at 0.9 and that of the Eu 3+ ions gradually increases from 0.01 to 0.08, the calculated ET efficiency (η ET ) from Tb 3+ to Eu 3+ ions increases from 7.9% for Gd 0.36 Tb 3.6 Eu 0.04 W 8 to 67.3% for Gd 0.08 Tb 3.6 Eu 0.32 W 8 . The energy transfer mechanism (Tb 3+ → Eu 3+ ) is a nonradiative dipole−dipole interaction. Furthermore, upon excitation at 370 nm, Eu 4 W 8 and Tb 4 W 8 show visible red-and green-emitting lights, respectively. When codoping trace amounts of Eu 3+ ions in Tb 4 W 8 , under excitation at 370 nm, Tb 3.92 Eu 0.08 W 8 displays near white-light emission.

No abstract

Two PIII–SbIII-heteroatom templated lanthanoid(Ln)-inserted polyoxotungstates [H2N(CH3)2]10NaH9[Ln4(H2O)14W7O15 (H2MA)4][SbIIIW9O33]2[HPIIISbIIIW15O54]2·44H2O [Ln = Nd3+ (1), Pr3+ (2)] embellished by DL-malic acid (H3MA) ligand were firstly achieved. The [Ln4(H2O)14W7O15(H2MA)4][SbIIIW9O33]2[HPIIISbIIIW15O54]220− polyanion is assembled from two trivacant...

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 III , P III )-directing lanthanoid (Ln)-inserted h eteropolyoxotungstates ( Ln-HPOTs),functionalized by 1,2,3-propanetricarboxylic acid (H 3 ptca) was a c h i e v e d . T h e i n t r i g u i n g t r i m e r i c [ L n 4 ( H12− polyanion was established by two trivacant [B-α-Sb III W 9 O 33 ] 9− segments mounted on both sides and one rare [HP III W 4 O 18 ] 8− segment at the bottom, which are bridged via an organic−inorganic hybrid [W 4 Ln 4 (H 2 O) 12 O 10 (H 2 ptca) 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.

Template-directed assembly of giant cluster-based nanomaterials is an everlasting theme in cluster science. In this work, ethylenediamine tetramethylphosphonic acid [H8EDTPA = (POCH2(OH)2)4C2H4N2] and [B-α-SbW9O33]9– were, respectively, used as an organic template and an inorganic template to prepare an organophosphonic acid-regulating PV–SbIII-heteroatom-inserted polyoxotungstate aggregate [H2N­(CH3)2]5Na11H9[CeW4O10(HEDTPA)­SbW15O50]­[B-α-SbW9O33]2·36H2O (1). Noteworthily, organophosphonic acid ligand not only works as an organic template leading to the assembly of a [HEDTPASbW15O50]14– building block but also further bridges the sandwich-type [CeW4O10(B-α-SbW9O33)2]11– entity. To extend its potential application in electrochemical sensing properties, we prepared a three-dimensional 1@EGO composite (EGO = reduced graphene oxide functionalized by ethylenediamine) with porous architecture and a prominent conducting ability. Furthermore, the 1@EGO composite was explored as a modification material for glassy carbon electrodes to build a dual-signal readout electrochemical aptasensor for carcinogens, which shows much better detection performance for aflatoxin B1 compared with traditional single-signal biosensors