Double Trigonal Pyramidal {SeO₃} Groups Bridged 2-Picolinic Acid Modified Cerium-Inlaid Polyoxometalate Including Mixed Selenotungstate Subunits for Electrochemically Sensing Ochratoxin A

Abstract

An organic–inorganic hybrid trigonal pyramidal {SeO3} group, bridged cerium-inlaid polyoxometalate (POM) Na16[Se2Ce4(H2O)8W4(HPIC)4O10]­[B-β-Se­W8­O30]2­[Se2­W12­O46]2·60H2O (1) (HPIC = 2-picolinic acid), containing two disparate selenotungstate (ST) building blocks was synthesized by a one-step assembly strategy, which is established by two asymmetric sandwich-type {[Ce2(H2O)4W2(HPIC)2O4]­[B-β-SeW8O30]­[Se2W12O46]}10– moieties joined by double trigonal pyramidal {SeO3} groups. Its outstanding structural trait is that it contains two types of ST building blocks, Keggin-type [B-β-SeW8O30]8– and Dawson-like [Se2W12O46]12–, which are extremely rare in ST chemistry. Remarkably, [Se2W12O46]12– is first obtained in lanthanide-inlaid STs. Furthermore, 1@PPy conductive film (PPy = polypyrrole) was prepared by electrochemical polymerization and served as the electrode material, and then nano-gold particles (NGPs) were deposited on the surface of 1@PPy conductive film by an electrochemical deposition method in order to immobilize the aptamer of ochratoxin A. With the help of exonuclease I (EN I), the oxidation peak of the metalized Ag works as the detection signal to achieve the detection of ochratoxin A (OTXA). This study offers an available approach for creating organic–inorganic hybrid heteroatom-bridged lanthanide-inlaid POMs and reveals the likelihood of extending heteroatom-bridged lanthanide-inlaid POMs into electrochemical biosensing applications.

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

“…The {SeW 9 } can be deemed as the hypothetical plenary Keggin [SeW 12 O 40 ] 4– (Figure f) cluster by removing a [W 3 O 13 ] 8– ({W 3 }) trimer. Generally speaking, most of lacunary SeT BUs are based on Keggin-type, Dawson-type BUs or their derivatives such as {SeW 8 }, {SeW 9 }, {Se 2 W 12 }, {Se 2 W 14 }, {Se 2 W 18 }, and so on (Figure S2), ,,, but a few “non-conventional” SeT BUs have been reported. Herein, {SeW 6 } in 1a is also a case of uncommon SeT BUs.…”

“…Selenotungstates (SeTs), as a burgeoning and promising branch of HPOM family, have attracted researchers’ vast interest and developed rapidly in recent years. − On one hand, the lone pair electrons stereochemical effect of Se IV HOA in SeTs can effectively preclude from generating the closed HPOM building units (BUs) and result in the formation of open and lacunary HPOM BUs, which can be deemed as peculiar inorganic ligands to combine functional metal cations for fabricating extraordinary architectures. On the other hand, the trigonal pyramidal SeO 3 2– anion can apply the self-carrying structure-directing effect to construct abundant SeT BUs. , In 2010, Cronin and collaborators reported several SeTs involving diverse BUs such as high-vacant {SeW 3 }, {SeW 8 }, and tri-vacant Keggin-type {SeW 9 } BUs .…”

“…First of all, as a kind of alkene organic ligand, FA owns a CC unsaturated double bond and C–C single bonds in structural characteristic, which means that this long carbon-chain ligand possesses the peculiarity of rigid ligands so that it can be used as structural template to form larger extended cluster structures. Second, FA has strong buffer effect to keep pH of the aqueous solution around 3.0 that is a good condition for constructing diverse SeT BUs. − ,− Third, Ln cations not only possess plentiful coordination modes that can help them in connecting POM fragments into polytropic aggregates but also have excellent properties such as high oxophilicity, remarkable luminescence capability, and so on. Meanwhile, as a typical multidentate ligand with two carboxylic groups, the FA ligand can provide more chance for introducing Ln cations to SeT backbones. − According to these ideas, we synthesized two FA-bridging OIHLFSeTs [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 )] and their polyanions are constructed from four trilacunary [B-α-SeW 9 O 33 ] 8– ({SeW 9 }) and two unprecedented [SeW 6 O 25 ] 10– ({SeW 6 }) BUs concatenated by a FA-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+ ({Ln 6 W 8 }) entity.…”

Dual-ligand-functionalized dodeca-nuclear lanthanide–tungsten-cluster incorporated selenotungstates and fluorescence detection of dipicolinic acid (an anthrax biomarker)

“…[18][19][20] Notably, flexible or rigid ligands serving as chelating or bridging linkers have been extensively applied to a POT system and have demonstrated their outstanding potential for the fabrication of high-nuclear metal-substituted or extended IOHPMs. 5,21,22 However, mixed-ligand-participated IOHPMs remain underexplored. For instance, the great potential of organic ligands applied to the POT system has been shown in the design and assembly of POT-organic frameworks based on inorganicorganic Ni 6 -substituted {Ni 6 (μ 3 -OH) 3 (H 2 O) 6 L n (B-α-PW 9 O 34 )} building blocks (BBs) (Fig.…”

Two Tetra-Nuclear Ln-Substituted Prazine Dicarboxylic Acid-Functionalized Selenotungstates with Catalytic Oxidation of Thioether Properties

“…Compared with the prior works, the rigid organic carboxylic-functionalized Ln-substituted SeTs are comparatively rare, which may be attributable to the presence of the steric hindrance effect, the lower activity, and the poor solubility of rigid ligands in reaction system. , Nevertheless, Zhao’s group has prepared a string of Ln-inlaid rigid carboxylic ligand-trimmed SeTs in very recent years. For example, they reported the 2-picolinic acid-functionalized Ce-insert SeTs Na 16 [Se 2 Ce 4 (H 2 O) 8 W 4 (HPIC) 4 O 10 ]­[B-β-SeW 8 O 30 ] 2 [Se 2 W 12 O 46 ] 2 ·60H 2 O by a simple one-step self-assembly reaction in 2022 . Beyond that, Zheng's group manufactured a distinctive Se-4f cluster-incorporated SeTs, H 18 {[(H 4 pic) 4 Eu 10 Se 13 O 28 (H 2 O) 12 ]­(α-GeW 9 O 34 ) 4 ·40H 2 O (H 4 pic= isonicotinic acid), which are the largest selenium-incorporated Se-4f cluster POMs presently reported, concurrent with the high Lewis acid–based catalytic activity was investigated .…”