Jingyang Niu

Structural and Catalytic Performance of a Polyoxometalate-Based Metal−Organic Framework Having a Lanthanide Nanocage as a Secondary Building Block

A polyoxometalate-based lanthanide-organic framework was achieved using the {[Ho(4)(dpdo)(8)(H(2)O)(16)BW(12)O(40)] (H(2)O)(2)}(7+) nanocage as a secondary building block for the heterogeneous catalysis of phosphodiester cleavage in an aqueous solution.

Nona-copper(II)-containing 18-tungsto-8-arsenate(III) exhibits antitumor activity

The nona-Cu(II)-containing tungstoarsenate(III) [H4{Cu(II)9As(III)6O15(H2O)6}(α-As(III)W9O33)2](8-) (1a) has been synthesized and characterized. Polyanion 1a comprises a unique, cylindrical {Cu(II)9As(III)6O15(H2O)6}(6+) cluster, which forms a large central cavity and is capped on either end by an [α-As(III)W9O33](9-) capping group. It exhibits remarkable activity against K562 leukaemia cells, as well as induces HepG2 cell apoptosis and autophagy.

Self‐Assembly of [B‐SbW9O33]9− Subunit with Transition Metal Ions (Mn2+, Cu2+, Co2+) in Aqueous Solution: Syntheses, Structures and Magnetic Properties of Sandwich Type Polyoxometalates with Subvalent SbIII Heteroatom

Rational self-assembly of Sb(2)O(3) and Na(2)WO(4), or (NH(4))(18)[NaSb(9)W(21)O(86)] with transition-metal ions (Mn(2+), Cu(2+), Co(2+)), in aqueous solution under controlled conditions yield a series of sandwich type complexes, namely, Na(2)H(2)[Mn(2.5)W(1.5)(H(2)O)(8)(B-beta-SbW(9)O(33))(2)]32 H(2)O (1), Na(4)H(7)[Na(3)(H(2)O)(6)Mn(3)(mu-OAc)(2)(B-alpha-SbW(9)O(33))(2)]20 H(2)O (OAc=acetate anion) (2), NaH(8)[Na(2)Cu(4)Cl(B-alpha-SbW(9)O(33))(2)]21 H(2)O (3), Na(8)K[Na(2)K(H(2)O)(2){Co(H(2)O)}(3)(B-alpha-SbW(9)O(33))(2)] 10 H(2)O (4), and Na(5)H[{Co(H(2)O)(2)}(3)W(H(2)O)(2)(B-beta-SbW(9)O(33))(2)]11.5 H(2)O (5). These structures are determined by using the X-ray diffraction technique and further characterized by obtaining IR spectra and performing elemental analysis. Structure analysis reveals that polyoxoanions in 1 and 5 comprise of two [B-beta-SbW(9)O(33)](9-) building units, whereas 2, 3, and 4 consist of two isomerous [B-alpha-SbW(9)O(33)](9-) building blocks, which are all linked by different transition-metal ions (Mn(2+), Cu(2+), or Co(2+)) with different quantitative nuclearity. It should be noted that compound 2 represents the first one-dimensional sinusoidal chain based on sandwich like tungstoantimonate building blocks through the carboxylate-bridging ligands. Additionally, 3 is constructed from sandwiched anions [Na(2)Cu(4)Cl(B-alpha-SbW(9)O(33))(2)](9-) linked to each other to form an infinitely extended 2D network, whereas 5 shows an interesting 3D framework built up from offset sandwich type polyoxoanion [{Co(H(2)O)(2)}(3)W(H(2)O)(2)(B-beta-SbW(9)O(33))(2)](6-) linked by Co(2+) and Na(+) ions. EPR studies performed at 110 K and room temperature reveal that the metal cations (Mn(2+), Cu(2+), Co(2+)) reside in a square-pyramidal geometry in 2, 3, and 4. The magnetic behavior of 1-4 suggests the presence of weak antiferromagnetic coupling interactions between magnetic metal centers with the exchange integral J=-0.552 cm(-1) in 2.

Rare‐Earth–Transition‐Metal Organic–Inorganic Hybrids Based on Keggin‐type Polyoxometalates and Pyrazine‐2,3‐dicarboxylate

Five rare-earth-transition-metal (RE-TM) heterometal organic-inorganic hybrids based on Keggin-type silicotungstates and mixed ligands H2pzda (pzda=pyrazine-2,3-dicarboxylate) and en (en=ethylenediamine) (enH2)[Cu(en)2(H2O)]2{[Cu(en)2][Cu(en)2(H2O)][(α-SiW11 O39)RE(H2O)(pzda)]}2·n H2O (n≈4; RE=YIII (1), DyIII (2), YbIII (3), and LuIII (4)) and [Cu(en)2(H2O)]2{[Cu(en)2]2[Cu(pzda)2][(α-H2SiW11O39)Ce(H2O)]2}·n H2O (5; n≈8) have been hydrothermally synthesized and structurally characterized. Compounds 1-5 all contain the dimeric mono-RE substituted Keggin [RE(α-SiW11O39)]210- subunits linked by H2pzda ligands. Interestingly, 1-4 exhibit discrete structures, in which the H2pzda ligand acts as a tetradentate ligand to bind the RE and Cu cations, whereas 5 displays a 1D double-chain architecture, in which the H2pzda ligand adopts a new pentadentate mode to connect the Ce and Cu cations. To our knowledge, 1-5 represent the first monovacant Keggin-type silicotungstates containing both RE-TM heterometals and mixed ligands. The luminescence of 2 is derived from the combination of the DyIII cations and H2pzda ligands, whereas the luminescence properties of 1 and 3-5 are attributable to the H2pzda ligands.

Assembly of polyoxometalate-based inorganic–organic compounds from silver–Schiff base building blocks: synthesis, crystal structures and luminescent properties

Three polyoxometalate-based inorganic–organic hybrid compounds constructed from silver(I)-L (L = N,N′-bis-pyridin-2-ylmethylene-hydrazine) species and saturated Keggin type polyoxoanions, {[Ag3L3](PW12O40)(CH3CN)(DMF)2.5}n (1), [Ag4L3(CH3CN)4][Ag2L(CH3CN)3](PMo12O40)2·CH3CN (2) and [(SiMo12O40){Ag2L(CH3CN)3}2]·(CH3CN)2 (3), have been synthesized and structurally characterized by IR spectroscopy, UV spectroscopy, thermogravimetric (TG) analyses and complete single crystal structure analyses. The structure of 1 containing [PW12O40]3− anions as templates exhibits a one-dimensional chain structure constructed by the coordination of a silver center and bis-bidentate bridging ligands with the pyridyl rings adopting a transoid configuration. Compound 2 displays an AB-type arrangement supramolecular structure, in which A is a two-dimensional sheet formed by linking the adjacent [Ag4L3(CH3CN)4]4+ units through the cooperativity of intermolecular π–π interactions and C–H⋯π interactions, while B is composed of [PMo12O40]3− anions and binuclear [Ag2L(CH3CN)4]2+ cations. Compound 3 exhibits a new bisupporting Keggin-polyoxometalate structure in which the [SiMo12O40]4− core supports two [Ag2L(CH3CN)3]2+ fragments in two opposite positions. The luminescent properties of L and 1–3 in the solid state were investigated.

A Nine-Coordinated Bismuth(III) Complex Derived from Pentadentate 2,6-Diacetylpyridine Bis(4N-methylthiosemicarbazone): Crystal Structure and Both in Vitro and in Vivo Biological Evaluation

Up to now, bismuth(III) complexes with thiosemicarbazones have been comparatively rare. Few in vivo biological studies have been carried out in comparison to the plentiful in vitro data. Here, an interesting nine-coordinated bismuth(III) complex, [Bi(H2L)(NO3)2]NO3 [1; H2L = 2,6-diacetylpyridine bis((4)N-methylthiosemicarbazone)], has been synthesized and structurally characterized. The analytical data reveal the formation of 1:1 (metal/ligand) stoichiometry. In vitro biological studies have indicated that the bismuth complex 1 has shown much higher antibacterial and anticancer activities than its parent ligand, especially with MIC = 10.66 μM against Bacillus cereus and Salmonella typhimurium and IC50 = 26.8 μM against K562 leukemia cells, respectively. More importantly, it also evidently inhibits H22 xenograft tumor growth on tumor-bearing mice (10 mg/kg; inhibitory rate = 61.6%). These results indicate that coordination to bismuth(III) might be an interesting strategy in the discovery of new anticancer drug candidates.

Four types of 1D or 2D organic–inorganic hybrids assembled by arsenotungstates and CuII–LnIII/IV heterometals

Four types of organic–inorganic hybrids Na[Cu(en)2(H2O)]4[Cu(en)2]2[Cu(H2O)4]0.5{Cu(en)2[H2CeIV(α-AsW11O39)2]2}·10H2O (1), Na3[Cu(en)2(H2O)][Cu(en)2]1.5[H3Ln(α-AsW11O39)2]·xH2O [Ln = PrIII, x = 5 (2); Ln = NdIII, x = 4.5 (3); Ln = SmIII, x = 5.5 (4); Ln = EuIII, x = 4 (5); Ln = TbIII, x = 4 (6)], [Cu(dap)(H2O)2]0.5[Cu(dap)2(H2O)]2[Cu(dap)2]3[Ln(α-AsW11O39)2]·xH2O [Ln = PrIII, x = 3 (7); Ln = EuIII, x = 3 (8)] and [Cu(dap)2]5.5[Ln(α-AsW11O39)2]·xH2O [Ln = TbIII, x = 6 (9); Ln = DyIII, x = 5 (10)] (en = ethylenediamine, dap = 1,2-diaminopropane) have been hydrothermally synthesized and fully characterized by elemental analyses, IR spectra, solid-state UV spectra, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. 1 exhibits the first 2D TM–Ln heterometallic sheet architecture with a 4-connected topology established by tetrameric [Cu(H2O)4{Cu(en)2[H2Ce(α-AsW11O39)2]2}2]26− units via [Cu(en)2]2+ bridges. 2–6 are isomorphic and display the unique 2D (6,3)-network topology constructed from 1 : 2-type [H3Ln(α-AsW11O39)2]8− units through [Cu(en)2]2+ linkers. 7–8 represent the first 1D “dendritic” chain-like TM–Ln heterometallic POMs based on the 1 : 2-type [Ln(α-AsW11O39)2]11− units. 9–10 are the unique 2D sheets built by 1 : 2-type [Ln(α-AsW11O39)2]11− units and [Cu(dap)2]2+ connectors, in which the [Ln(α-AsW11O39)2]11− subunits act as 5-connected nodes and adjacent 2D sheets are packed in the mode of –AAA–. The photocatalytic measurements show that 1–10 can to some extent inhibit the photodegradation of rhodamine-B (RhB). Moreover, the luminescence properties of 5–6 and 8–9 have been investigated.

Three-dimensional homochiral manganese–lanthanide frameworks based on chiral camphorates with multi-coordination modes

A series of 3D homochiral manganese-lanthanide frameworks have been synthesized based on chiral camphoric acid. In the heterometallic features, D-camphoric acids are unprecedentedly embedded in three coordination modes.

Three-dimensional lanthanide polyoxometalate organic complexes: correlation of structure with properties

A family of three-dimensional (3D) architectures based on lanthanide-substituted polyoxotungstate building blocks [Ln(HL)(L)(H2O)6{Ln(H2L)0.5(α-PW11O39H)Ln(H2O)4}]2·nH2O (Ln = La, n = 8 (1); Ln = Ce, n = 12 (2); Ln = Pr, n = 8 (3); H2L = 2,5-pyridinedicarboxylic acid) have been successfully synthesized under hydrothermal conditions and further characterized by elemental analyses, X-ray powder diffraction (XRPD), IR spectra, UV spectra, thermogravimetric (TG) analyses and single-crystal X-ray diffraction. The common features of 1–3 are that they all consist of 1D zigzag chain [{Ln(α-PW11O39H)}2]6− moieties and the chains further form into 3D structure via metal–organic cations. Furthermore, the photocatalysis properties of 1–3 for degradation of the rhodamine-B (RhB) upon 500 W Hg lamp irradiation have been examined. The magnetic properties of compounds 2 and 3 have been studied by measuring their magnetic susceptibility in the temperature range of 2–300 K.

Two 1-D multi-nickel substituted arsenotungstate aggregates

Two multi-nickel substituted arsenotungstate aggregates [enH2]2[Ni(H2O)4]2[Ni(en)2]2[Ni(en)]2{[(α-AsW6O26)Ni6(OH)2(H2O)3(en)(B-α-AsW9O34)]2[W4O16][Ni3(H2O)2(en)]2}·16H2O (1) and [Ni(H2O)(en)2]2[Ni(H2O)3(en)][Ni(H2O)(en)]{[(α-AsW6O26)Ni6(OH)2(en)2.5(B-α-AsW9O34)]2H4[W4O16][Ni4(H2O)2(en)2]2}·13H2O (2) (en = ethylenediamine) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, UV spectra and single-crystal X-ray diffraction. 1 is a 1D chain architecture built by eighteen NiII substituted {[(α-AsW6O26)Ni6(OH)2(H2O)3(en)(B-α-AsW9O34)]2[W4O16][Ni3(H2O)2(en)]2}16− units via two [Ni(H2O)4]2+ and two [Ni(en)2]2+ bridges. 2 also displays a 1D chain motif constructed from twenty NiII substituted {[(α-AsW6O26)Ni6(OH)2(en)2.5(B-α-AsW9O34)]2H4[W4O16][Ni4(H2O)2(en)2]2}8− units via single en bridges. Notably, 1 and 2 not only represent rare eighteen/twenty NiII substituted arsenotungstates, but also display an unusual construction motif simultaneously containing the trivacant Keggin [B-α-AsW9O34]9−, hexavacant Keggin [α-AsW6O26]11− and tetrameric [W4O16]8− fragments. Magnetic measurements demonstrate that 1 and 2 indicate the ferromagnetic couplings within NiII centers.