Chiral [Mo₈O₂₆]^4– Polyoxoanion-Induced Three-Dimensional Architectures With Homochiral Eight-Fold Interpenetrated Metal–Organic Frameworks

A pair of novel chiral compounds based on homochiral 8-fold interpenetrated metal–organic frameworks (MOFs) and chiral polyoxometalates (POMs), formulated as d-[Cu­(4,4′-bipy)_1.5]₄­[Mo₈O₂₆] (d-<b>1</b>) and l-[Cu­(4,4′-bipy)_1.5]₄­[Mo₈O₂₆] (l-<b>1</b>) (4,4′-bipy = 4,4′-bipyridine), have been successfully synthesized and characterized by single crystal X-ray diffraction, infrared, thermogravimetric analysis, elemental analysis, and solid circular dichroism spectra. Structural analysis indicates that two compounds are enantiomers. The connection of copper cations and 4,4′-bipy ligands generates helical infinite chains, while adjacent chains are further linked by Cu–N bonds to form a three-dimensional interpenetrating framework with a (10,3)-a topology. Interestingly, the chiral [Mo₈O₂₆]^4– polyanions are encapsulated in the chiral MOFs via sharing the oxygen atoms. Both d- and l-[Cu­(4,4′-bipy)_1.5]₄­[Mo₈O₂₆] crystallize in chiral space group <i>C</i>222₁. Additionally, two compounds represent new examples of chiral self-assembly

Syntheses, Structures, Luminescence, and Magnetic Properties of a Series of Novel Coordination Polymers Constructed by Nanosized [Ln₈Fe₄] Rings

A total of five three-dimensional Ln-Fe coordination polymers (CPs) [(CH₃)₂NH]­[(CH₃)₂NH₂]­[Ln₂Fe­(SO₄)₄(L)]­·3H₂O (Ln = Eu, <b>1</b>; Dy, <b>2</b>; Gd, <b>3</b>; Sm, <b>4</b>; Er, <b>5</b>; H₂L = tartaric acid) have been successfully synthesized under solvothermal conditions and characterized by infrared spectroscopy, thermogravimetric analysis, elemental analyses, luminescence, and magnetic properties. Structural analysis indicates that the frameworks of <b>1</b>–<b>5</b> are constructed from novel [Ln₈Fe₄] rings. In the strcutures of <b>1</b>–<b>5</b>, Ln^III and Fe^III ions interconnect through O donors of sulfate anions to generate a one-dimensional chain, and the adjacent chains are joined together by ligand [L]^2– to form a two-dimensional zonary plane, which is further bridged by ligand [L]^2– to give a new topology and named as “<i><b>Xhd</b></i><b>1</b>”. Magnetic properties of <b>2</b> and <b>3</b> were investigated using variable temperature magnetic susceptibility, and weak ferromagnetic exchange between the Fe^III and Ln^III ions has been established for the Gd derivative. Meanwhile, we also studied luminescence spectra and luminescence lifetimes of <b>1</b> and <b>4</b> in the solid state at room temperature. The luminescence lifetime of <b>1</b> is 0.98 ms, which is significantly longer than the values in the reported Eu³⁺ coordination polymers

An Unprecedented M–O Cluster Constructed from Nanosized {[C₅NH₅]₉[H₃₁Mo^V₁₂O₂₄Co^II₁₂(PO₄)₂₃(H₂O)₄]}^2– Anions Exhibiting Interesting Nonlinear-Optical Properties

A novel high-nuclear nanosized cluster modified by conjugated organic ligands (pyridine and imidazole), [C₅NH₅]₈­[C₃H₅N₂]₂­{[C₅NH₅]₉​­[H₃₁Mo₁₂O₂₄Co₁₂​­(PO₄)₂₃­(H₂O)₄]}·12H₂O (<b>1</b>), has been successfully isolated under hydrothermal conditions and structurally characterized. Compound <b>1</b> consists of 12 Co^II and 12 Mo^V ions linked by 23 {PO₄} groups, exhibiting unprecedented nanosized ship-shaped clusters. The magnetic measurements reveal that compound <b>1</b> exhibits dominant antiferromagnetic interactions. Additionally, pyridine and imidazole ligands enhance the delocalized electron effects of clusters, and the third-order nonlinear-optical response of compound <b>1</b> is excellent

POM Constructed from Super-Sodalite Cage with Extra-Large 24-Membered Channels: Effective Sorbent for Uranium Adsorption

A POMs-based sorbent functionalized by phosphate groups: H₃₃Na₁₄Mo^V₂₄Mo^VI₂(PO₄)₁₁O₇₃ has been successfully isolated under hydrothermal conditions. The cooperative assembly of the ring-shaped polyoxometalate structural building unit {P₄Mo₆} and MoO₄ tetrahedra linkers gives rise to an unprecedented supersodalite cage containing approximately spherical cavities with a 8.76 Å diameter. As POMs-based inorganic material, compound <b>1</b> was first applied as sorbent to adsorb U­(VI) from aqueous solution, exhibiting good stability, high efficiency, and selectivity. The maximum sorption capacity reaches 325.9 mg g^–1, which may capture radionuclides through cooperative binding of the phosphate groups. The adsorbed U­(VI) could be nearly drastically eluted when using 0.1 M Na₂CO₃ and the sorption capacity for U­(VI) slightly decreased 10.16% through five successive sorption/desorption cycles. This work represents first application of POMs-based inorganic materials as sorbent to adsorb uranium from aqueous solution and provides a feasible approach for the entrapment and recovery of radionuclides

POM Constructed from Super-Sodalite Cage with Extra-Large 24-Membered Channels: Effective Sorbent for Uranium Adsorption

A POMs-based sorbent functionalized by phosphate groups: H₃₃Na₁₄Mo^V₂₄Mo^VI₂(PO₄)₁₁O₇₃ has been successfully isolated under hydrothermal conditions. The cooperative assembly of the ring-shaped polyoxometalate structural building unit {P₄Mo₆} and MoO₄ tetrahedra linkers gives rise to an unprecedented supersodalite cage containing approximately spherical cavities with a 8.76 Å diameter. As POMs-based inorganic material, compound <b>1</b> was first applied as sorbent to adsorb U­(VI) from aqueous solution, exhibiting good stability, high efficiency, and selectivity. The maximum sorption capacity reaches 325.9 mg g^–1, which may capture radionuclides through cooperative binding of the phosphate groups. The adsorbed U­(VI) could be nearly drastically eluted when using 0.1 M Na₂CO₃ and the sorption capacity for U­(VI) slightly decreased 10.16% through five successive sorption/desorption cycles. This work represents first application of POMs-based inorganic materials as sorbent to adsorb uranium from aqueous solution and provides a feasible approach for the entrapment and recovery of radionuclides

l- and d‑[LnZn(IN)₃(C₂H₄O₂)]_<i>n</i> (Ln = Eu, Sm, and Gd): Chiral Enantiomerically 3D 3d–4f Coordination Polymers Constructed by Interesting Butterfly-like Building Units and −[Ln-O-Zn]_<i>n</i>– Helices

A total of six three-dimensional chiral coordination compounds l- and d-[LnZn­(IN)₃­(C₂H₄O₂)]_<i>n</i> (Ln = Eu, Sm, and Gd; HIN = isonicotinic acid) have been successfully synthesized under hydrothermal conditions without any chiral auxiliary and characterized by IR, TG, elemental analyses, and solid-state circular dichroism spectra. The structures of <b>1</b>–<b>6</b> were determined by single-crystal X-ray structural analysis, which shows that l-[LnZn­(IN)₃­(C₂H₄O₂)]<i>_n</i> (Ln = Eu (<b>1</b>), Sm (<b>2</b>), and Gd (<b>3</b>)) crystallize in space group <i>P</i>6₅22 and are levogyrate. The chiral frameworks of l-[LnZn­(IN)₃(C₂H₄O₂)]_<i>n</i> are constructed from l-helical Ln-O-Zn cluster chains, while adjacent l-type helical −[Ln-O-Zn]_<i>n</i>– chains are connected through IN^– ligands. d-[LnZn­(IN)₃­(C₂H₄O₂)]_<i>n</i> (Ln = Eu (<b>4</b>), Sm (<b>5</b>), and Gd (<b>6</b>)) crystallize in space group <i>P</i>6₁22, and their chiral frameworks consist of d-helical Ln-O-Zn cluster chains. The observed second-harmonic generation efficiencies of [EuZn­(IN)₃­(C₂H₄O₂)]_<i>n</i>, [SmZn­(IN)₃­(C₂H₄O₂)]_<i>n</i>, and [GdZn­(IN)₃­(C₂H₄O₂)]_<i>n</i> are 0.4, 0.3, and 0.3 times that of urea, respectively. We also studied luminescence spectra and luminescence lifetimes of <b>1</b> and <b>2</b>. The luminescence lifetimes of <b>1</b> and <b>2</b> are 1.18 ms, and 29.6 μs, respectively