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Niu J Ma P Niu H Li J Zhao J Song Y Wang J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(31):8739-8748
Rational self-assembly of hexaniobate Lindqvist-type precursor [HNb6O19]7- with soluble Cu2+ salts utilizing different strategies produces a series of giant polyniobate clusters, namely, (H2en)1.25[Cu(en)2(H2O)]2Cl4[Nb24O72H21.5]7 H2O (1; en: ethylenediamine), [Cu(en)2]3[Cu(en)2(H2O)]9[{H2Nb6O19} subset{[({KNb24O72H10.25}{Cu(en)2})2{Cu3(en)3(H2O)3}{Na1.5Cu1.5(H2O)8}{Cu(en)2}4]6}]144 H2O (2), K12Na4[H23NaO8Cu24(Nb7O22)8]106 H2O (3), and K16Na12[H9Cu25.5O8(Nb7O22)8] 73.5 H2O (4). Their structures were determined and further characterized by single-crystal X-ray diffraction analysis, IR and Raman spectroscopy, thermogravimetric analysis (TGA), and elemental analysis. Structural analyses reveal that compound 2 comprises a giant capsule anion based on a wheel-shaped cluster encapsulating a Lindqvist diprotonated cluster [H2Nb6O19]6- unit, and forms a honeycomb-like structure with the inclusion of Lindqvist-type anions [H2Nb6O19]6- in the holes, whereas 3 and 4 represent an unprecedented giant cube-shaped framework. All the compounds are built from [Nb7O22]9- fundamental building blocks. Solution Raman spectroscopy studies of 2 and 3 reveal that the solid-state structures of these polyniobate cluster anions disassemble and exist in the form of the [Nb6O19]8- unit in solution. Magnetic susceptibility measurement of 3 shows antiferromagnetic coupling interactions between CuII ions with the spin-canting phenomenon. 相似文献
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Sylvain Gatard Dr. Sébastien Blanchard Dr. Bernd Schollhorn Prof. Pierre Gouzerh Prof. Anna Proust Prof. Kamal Boubekeur Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(28):8390-8399
The electroactive benzothiazole hydrazone AMBTH–H2, a new member of the 2,2′‐azino‐bis(N‐alkylbenzothiazole) family, was synthesised in a five‐step procedure and characterised by using X‐ray diffraction along with two intermediates and the N‐methylbenzothiazole hydrazone MBTH–H2. Both AMBTH–H2 and MBTH–H2 were coupled to [Mo6O19]2? in acetonitrile in the presence of dicyclohexylcarbodiimide and dimethylaminopyridine to give two new diazoalkane–hexamolybdates, which were isolated as tetrabutylammonium salts and characterised by using IR, UV/Vis and NMR spectroscopies, cyclic voltammetry and, for one of them, X‐ray diffraction. The packing arrangement molecules in crystals of AMBTH–H2, the redox features of the AMBTH–hexamolybdate hybrid together with a good electronic communication between the organic π system and the molybdenum centres make these compounds very promising blocks for the synthesis of conducting molecular materials. 相似文献
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Dr. Natalya V. Izarova Aleksandar Kondinski Dr. Nina Vankova Prof. Dr. Thomas Heine Patrick Jäger Dr. Florian Schinle Dr. Oliver Hampe Prof. Dr. Ulrich Kortz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8556-8560
The first fully inorganic, discrete gold–palladium–oxo complex [NaAuIII4PdII8O8(AsO4)8]11? has been synthesized in aqueous medium. The combination of single‐crystal XRD, elemental analysis, mass spectrometry, and DFT calculations allowed establishing the structure and composition of the novel polyanion, and UV/Vis studies suggest that it is stable in neutral aqueous media. 相似文献
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Rational self‐assembly of Sb2O3 and Na2WO4, or (NH4)18[NaSb9W21O86] with transition‐metal ions (Mn2+, Cu2+, Co2+), in aqueous solution under controlled conditions yield a series of sandwich type complexes, namely, Na2H2[Mn2.5W1.5(H2O)8(B‐β‐SbW9O33)2]?32 H2O (1) , Na4H7[Na3(H2O)6Mn3(μ‐OAc)2(B‐α‐SbW9O33)2]?20 H2O (OAc=acetate anion) (2) , NaH8[Na2Cu4Cl(B‐α‐SbW9O33)2]?21 H2O (3) , Na8K[Na2K(H2O)2{Co(H2O)}3(B‐α‐SbW9O33)2]? 10 H2O (4) , and Na5H[{Co(H2O)2}3W(H2O)2(B‐β‐SbW9O33)2]?11.5 H2O (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‐β‐SbW9O33]9? building units, whereas 2 , 3 , and 4 consist of two isomerous [B‐α‐SbW9O33]9? building blocks, which are all linked by different transition‐metal ions (Mn2+, Cu2+, or Co2+) 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 [Na2Cu4Cl(B‐α‐SbW9O33)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(H2O)2}3W(H2O)2(B‐β‐SbW9O33)2]6? linked by Co2+ and Na+ ions. EPR studies performed at 110 K and room temperature reveal that the metal cations (Mn2+, Cu2+, Co2+) 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 . 相似文献
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Titanium‐Substituted Polyoxotantalate Clusters Exhibiting Wide pH Stabilities: [Ti2Ta8O28]8− and [Ti12Ta6O44]10−
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Dr. Jung‐Ho Son Prof. William H. Casey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14155-14157
Two new substituted polyoxotantalate clusters, [Ti2Ta8O28]8? and [Ti12Ta6O44]10?, considerably expand the pH range where tantalates persist in aqueous solution. The structures of [Ti2Ta8O28]8? and [Ti12Ta6O44]10? are reported as tetramethylammonium salts after synthesis at hydrothermal conditions in aqueous solution. These Ti‐substituted polyoxotantalate clusters have analogues among recently discovered niobates, but are slightly larger and more persistent in solution. Most importantly, they exhibit a much wider range of pH stability than the familiar hexatantalate cluster, which is the only other tantalate known to be stable at highly basic pH conditions. These molecules are kinetically stable to near‐neutral pH, making them excellent synthons for further development into materials and catalysts, and an significant advance in adapting tantalates for use in aqueous solutions. 相似文献
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Ronny Neumann Prof. Daniella Goldfarb Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(33):10014-10020
An in‐depth spectroscopic EPR investigation of a key intermediate, formally notated as [PVIVVVMo10O40]6? and formed in known electron‐transfer and electron‐transfer/oxygen‐transfer reactions catalyzed by H5PV2Mo10O40, has been carried out. Pulsed EPR spectroscopy have been utilized: specifically, W‐band electron–electron double resonance (ELDOR)‐detected NMR and two‐dimensional (2D) hyperfine sub‐level correlation (HYSCORE) measurements, which resolved 95Mo and 17O hyperfine interactions, and electron–nuclear double resonance (ENDOR), which gave the weak 51V and 31P interactions. In this way, two paramagnetic species related to [PVIVVVMo10O40]6? were identified. The first species (30–35 %) has a vanadyl (VO2+)‐like EPR spectrum and is not situated within the polyoxometalate cluster. Here the VO2+ was suggested to be supported on the Keggin cluster and can be represented as an ion pair, [PVVMo10O39]8?[VIVO2+]. This species originates from the parent H5PV2Mo10O40 in which the vanadium atoms are nearest neighbors and it is suggested that this isomer is more likely to be reactive in electron‐transfer/oxygen‐transfer reaction oxidation reactions. In the second (70–65 %) species, the VIV remains embedded within the polyoxometalate framework and originates from reduction of distal H5PV2Mo10O40 isomers to yield an intact cluster, [PVIVVVMo10O40]6?. 相似文献
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Tetradecacobalt(II)‐Containing 36‐Niobate [Co14(OH)16(H2O)8Nb36O106]20− and Its Photocatalytic H2 Evolution Activity
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Prof. Jingyang Niu Fang Li Dr. Junwei Zhao Pengtao Ma Dr. Dongdi Zhang Dr. Bassem Bassil Prof. Ulrich Kortz Prof. Jingping Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9852-9857
A gigantic Co14‐containing 36‐niobate, Na12K8[Co14(OH)16(H2O)8Nb36O106] ? 71H2O ( 1 ), has been prepared by the hydrothermal method and structurally characterized. Polyanion [Co14(OH)16(H2O)8Nb36O106]20? ( 1 a ) comprises a central Co7 core, surrounded by another seven isolated Co2+ ions and six Lindqvist‐type (Nb6O19) hexaniobate fragments. This is the first example of a high‐nuclear cobalt‐cluster‐containing polyoxoniobate. The photocatalytic H2 evolution activity of Pt‐loaded 1 was observed in methanol solution under irradiation using a 300 W Xe lamp. 相似文献