Divacant polyoxotungstates: reactivity of the gamma-decatungstates [γ-XW10O36]8-(X = Si, Ge)

The dilacunary, Keggin-based gamma-decatungstate ions [γ-XW(10)O(36)](8-) (X = Si, Ge) {XW(10)} exhibit an exciting and versatile solution chemistry, which is probably unmatched by any other lacunary polytungstate. The reactivity of {XW(10)} in the presence, and even absence, of electrophiles, includes loss/gain of tungsten, isomerization, and dimerization. Ever since the syntheses and structures of {XW(10)} were reported, many research groups around the world have investigated the reactivity of these polyanions towards nucleophiles (mostly d-block metal ions) and different products with various shape, size and composition were obtained. Here we provide an overview of the state-of-the-art in this subarea of polyoxometalate chemistry, with a focus on synthetic and structural aspects.     

(NH4)6[Mn3B6P9O36(OH)3]·4H2O: a new open-framework manganese borophosphate synthesized by using boric acid flux method

A new three-dimensional (3-D) open-framework manganese borophosphate, (NH(4))(6)[Mn(3)B(6)P(9)O(36)(OH)(3)]·4H(2)O (denoted as MnBPO-CJ31), has been synthesized by using boric acid flux method. Its anionic framework structure is constructed by the connection of MnO(6) octahedra and BO(4), PO(4) and PO(3)(OH) tetrahedra. It contains 12-ring channels along the [001] direction with a pore diameter of 7.1 ?. It is the first borophosphate featuring a 3-D anionic partial structure with a B/P ratio of 2/3 and an unprecedented fifteen mer tetrahedral fundamental building unit (FBU) [B(6)P(9)O(36)(OH)(3)] exists in this compound. NH(4)(+) ions locate in the void space to balance the negative charge of the inorganic framework. The compound is further characterized by powder XRD, ICP, CHN, TGA and IR analyses. Magnetic study reveals that MnBPO-CJ31 shows interesting canted antiferromagnetic behaviour at low temperature.     

Syntheses,structures and properties of two complexes bridged by [M(CN)2] − (M = Ag (I), Au (I))

A dinuclear complex Cu₂(bpca)₂(H₂O)₂(Ag₂(CN)₃) (1) and a 1D complex [Cu₂(bpca)₂(H₂O)₂(Au(CN)₂)₂] _n (2) (bpca = bis(2-pyridylcarbonyl)amide anion) have been prepared, structurally characterized and 2 has been magnetically characterized. The magnetic properties show an antiferromagnetic interaction between the two Cu(II) ions. Based on the Hamiltonian ? = ?2J Σ (S_i · S_{i +1}), best fitting for the experimental data leads to J = ?0.045 cm^?1.     

STRUCTURAL CHEMISTRY OF EIGHT-COORDINATE COMPLEXES OP MNTHANOID WITH BIDBNTATE LIGANDS IV.CRYSTAL STRUCTURES OF [C_4H_8OH] [Eu(S_2CNC_4H_8)_4]·xC_4H_8O(x=2,0)

<正> Compound [C4H3OH][Eu(S2CNC4H3)4].2C4H8O(I), Mr=953,80,monoclinic, P21/n,a = 11,332(3), b= 22,837(5), c= 15.671(2)A,β= 94.93(1)°, V= 4040.2 A3,Z= 4,Dc = 1.567 g/cm3. [C4H8OH][Bu(S2CNC4H8)4] (2),Mr=809.72, monoclinic,P 21/c,a= 12.184(2), b= 15.181(3), c= 18.334(3)A,β=98.57(1)°,V=3353,3 A3,Z = 4, Dc= 1.605 g/cm3. The Eu atom in the anions of 1 and 2 is coordinated by eight S atoms frow four S2CNC4H8 chelate groups in the form of a dodecahedron with approximate D2d symmetry.     

Barrier to internal rotation around isopropyl—nitrogen bond of some N,N-di-isopropyldithio-and -diselenocarbamate complexes of tin (IV), X2Sn[Y2CN(Pr-i)2]2 (X = Cl,Me; Y = S,Se)

Line shape analysis of the variable temperature ¹H NMR spectra of X₂Sn[S₂CN(Pr-i)₂]₂ (X = Cl(1), Me(2)) and X₂Sn[Se₂CN(Pr-i)₂]₂ (X = Cl (3), Me (4)) in chloroform was carried out to obtain the activation parameters of internal rotation around the isopropyl-nitrogen bond. The barriers to internal rotation, E_a = 18.3 (1), 16.4 (2), 16.5 (3) and 13.9 (4) kcal/mol, are discussed in terms of the difference of the steric repulsion between the isopropyl group and the sulfur or selenium atom.     

Two Novel Chiral Inorganic–Organic Hybrid Materials Containing Preyssler and Wells–Dawson Heteropolyoxometallates with Valine (val), Glycine (gly), and Proline (pro) Amino acids: (Hval)2(Hgly)(H3O)6K5[Na(H2O)P5W30O110]·19.5H2O and (Hpro)6[P2W18O62]·8H2O

Two novel chiral organic?Cinorganic hybrid materials based on two important heteropolyoxometallate namely Preyssler and Wells?CDawson anions, (Hval)₂(Hgly)(H₃O)₆K₅[Na(H₂O)P₅W₃₀O₁₁₀]·19.5H₂O (1) and (Hpro)₆[P₂W₁₈O₆₂]·8H₂O (2), were prepared and characterized by elemental analysis, X-ray diffraction, and infrared spectroscopy. The mixed amino acid as cations, Preyssler and Wells?CDawson as anions held together into a 3D-network through hydrogen-bonding interactions. The most unique structural features of 1 and 2 are their 3D-inorganic infinite tunnel-like framework. It results a weak van der Waals interlayer interaction. This provides a desirable condition to use its potential as a host in a host?Cguest complex. The chirallity for these two crystal structures, with the space group P2₁ has been observed. The electrostatic forces and hydrogen bonding, keep these ????adducts???? stable in the solid state.     

Synthesis and characterization of heteronuclear germanium(IV) and lanthanum(III) (chromium(III)) complexes with 1,3-diamino-2-propanoltetraacetic acid: Crystal and molecular structure of [Ge(OH)(μ-Hpdta)(μ-OH)La(H2O)4] · H2O

Two heteronuclear germanium(IV) and lanthanum(III) (chromium(III)) complexes with 1,3-diamino-2-propanoltetraacetic acid (H₅Hpdta) have been synthesized. The compounds have been characterized by elemental analysis and X-ray powder diffraction data. The structure of [Ge(OH)(??-Hpdta)(??-OH)La(H₂O)₄] · H₂O (I) has been determined by X-ray crystallography. The crystals are monoclinic, a = 9.3805(3) ?, b = 10.3023(4) ?, c = 21.6527(6) ?, ?? = 94.829(2)°, V = 2085.10(12) ?³, Z = 4, space group P2₁/n, R1 = 0.0294 based on 5480 reflections with I > 2??(I). Compound I is composed of binuclear [Ge(OH)(??-Hpdta)(??-OH)La(H₂O)₄] molecules and crystal water molecules. In the dimeric molecule, the germanium and lanthanum atoms are linked by the bridging oxygen atom of the hydroxo ligand and the oxygen atom of the deprotonated isopropanol group of Hpdta^5?. The coordination spheres of germanium and lanthanum each contains one nitrogen atom and two carboxyl oxygen atoms of the four acetate arms of the heptadentate Hpdta^5? ligand. The Ge coordination polyhedron is completed to a distorted octahedron by the oxygen atom of the terminal hydroxo group, and the lanthanum coordination polyhedron is completed to a nine-vertex polyhedron by the oxygen atoms of four water molecules. In crystal, the complex molecules and crystal water molecules are combined by a system of hydrogen bonds.     

Synthesis, Characterization and Catalysis of New Pillared Anionic Clays by [GaW_(11)O_(39)M(H_2O)]~(7-)(M=Mn~(2 ),Co~(2 ) or Ni~(2 ))

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Hydrothermal Syntheses and Structural Characterizations of Two ML-Containing Polyoxomolybdates:[Cu~Ⅱ_2(HL)_3]_2[Mo_8O_(26)]·(H_2O)_4 and [Ni~Ⅱ(HL)_3]_2(Mo_8O_(26))·(H_2O)_3(HL=3-(2-Pyridyl)pyrazole)

Two new polyoxomolybdate compounds,namely CuII2(HL)3]2[Mo8O26]·(H2O)4(1) and [NiII(HL)3]2(Mo8O26)·(H2O)3(2)(HL = 3-(2-pyridyl)pyrazole),were designed and synthesized under hydrothermal conditions.X-ray diffraction analyses reveal that compound 1 consists of one β-Mo8O264-cluster and a Cu2 dimer which is built from two Cu(II) ions linked by three 3-(2-pyridyl)pyrazole ligands.Compound 2 is generated by two kinds of polyoxomolybdate clusters of α-[Mo8O26]4-and β-[Mo8O26]4-.In complexes 1 and 2,the multi-dimensional frameworks are con-structed with the help of hydrogen-bonding links between the terminaloxygen atoms of [Mo8O26]4-,water molecules,and 3-(2-pyridyl)pyrazole ligands.Crystal data of 1:C24H25Cu2Mo4N9O15,Mr = 1190.37,monoclinic,space group P21/c,a = 10.850(2),b = 18.510(4),c = 17.230(3) ,β = 100.57(3)°,V = 3401.6(12) 3,Z = 4,Dc = 2.324 g/cm3,F(000) = 2312,μ = 2.742 mm-1,R = 0.0302 and wR = 0.0775(Ⅰ 2σ(Ⅰ));Crystal data for 2:C48H48Mo8N18Ni2O29,Mr = 2225.98,monoclinic,space group P21/n,a = 20.799(2),b = 14.7970(13),c = 23.141(2) ,β = 91.6180(10)°,V = 7119.0(11) 3,Z = 4,Dc = 2.077 g/cm3,F(000) = 4344,μ = 1.968 mm-1,R = 0.0309 and wR = 0.0696(Ⅰ 2σ(Ⅰ)).     

Synthesis and Spectroscopic Characterization of Organothiophosphoryl Polyoxotungstates α- [C6H11P (S) ]2Xn+W11O39(8-n)- (Xn+ = P5+, Si4+, Ge4+, Ga3+)

Organothiophosphoryl polyoxotungstate derivatives α-C6H11P(S)]2Xn W11O39(8-n)- (X=P, Si, Ge, Ga)were obtained by the reactions of the monovacant α-[Xn W11O39](12-n)- (X=P, Si, Ge, Ga) anions with electrophilic C6H11P(S)Cl2 in acetonitrile. These new organic-inorganic hybrid anions were characterized by elemental analyses, IR, 31P and 183W NMR spectrometries. The six-line 183W NMR spectrum indicates that [C6H11P (S) ]2Xn W11O39(8-n)- (X= P, Si, Ge, Ga) anions possess true Cs symmetry in acetonitrile. According to the spectroscopic observation and the chemical analyses, it is known that each of the hybrid anions consists of an α-[XW11O3)] framework on which two equivalent C6H11P(S) groups are grafted through P-O-W bridges.     

Two isotypic transition metal germanophosphates M(II)4(H2O)4[Ge(OH)2(HPO4)2(PO4)2] (M(II) = Fe, Co): synthesis, structure, Mössbauer spectroscopy, and magnetic properties

Synthetic, structural, thermogravimetric, M?ssbauer spectroscopic, and magnetic studies were performed on two new isotypic germanophosphates, M(II)(4)(H(2)O)(4)[Ge(OH)(2)(HPO(4))(2)(PO(4))(2)] (M(II) = Fe, Co), which have been prepared under hydro-/solvo-thermal conditions. Their crystal structures, determined from single crystal data, are built from zigzag chains of M(II)O(6)-octahedra sharing either trans or skew edges interconnected by [GeP(4)O(14)(OH)(4)](8-) germanophosphate pentamers to form three-dimensional neutral framework structure. The edge-sharing M(II)O(6)-octahedral chains lead to interesting magnetic properties. These two germanophosphates exhibit a paramagnetic to antiferromagnetic transition at low temperatures. Additionally, two antiferromagnetic ordering transitions at around 8 and 6 K were observed for cobalt compound while only one at 19 K for the iron compound. Low-dimensional magnetic correlations within the octahedral chains are also observed. The divalent state of Fe in the iron compound determined from the M?ssbauer study and the isothermal magnetization as well as thermal analyses are discussed.     

Synthesis of a uranium(VI)-carbene: reductive formation of uranyl(V)-methanides, oxidative preparation of a [R2C═U═O]2+ analogue of the [O═U═O]2+ uranyl ion (R = Ph2PNSiMe3), and comparison of the nature of U(IV)═C, U(V)═C, and U(VI)═C double bonds

We report attempts to prepare uranyl(VI)- and uranium(VI) carbenes utilizing deprotonation and oxidation strategies. Treatment of the uranyl(VI)-methanide complex [(BIPMH)UO(2)Cl(THF)] [1, BIPMH = HC(PPh(2)NSiMe(3))(2)] with benzyl-sodium did not afford a uranyl(VI)-carbene via deprotonation. Instead, one-electron reduction and isolation of di- and trinuclear [UO(2)(BIPMH)(μ-Cl)UO(μ-O){BIPMH}] (2) and [UO(μ-O)(BIPMH)(μ(3)-Cl){UO(μ-O)(BIPMH)}(2)] (3), respectively, with concomitant elimination of dibenzyl, was observed. Complexes 2 and 3 represent the first examples of organometallic uranyl(V), and 3 is notable for exhibiting rare cation-cation interactions between uranyl(VI) and uranyl(V) groups. In contrast, two-electron oxidation of the uranium(IV)-carbene [(BIPM)UCl(3)Li(THF)(2)] (4) by 4-morpholine N-oxide afforded the first uranium(VI)-carbene [(BIPM)UOCl(2)] (6). Complex 6 exhibits a trans-CUO linkage that represents a [R(2)C═U═O](2+) analogue of the uranyl ion. Notably, treatment of 4 with other oxidants such as Me(3)NO, C(5)H(5)NO, and TEMPO afforded 1 as the only isolable product. Computational studies of 4, the uranium(V)-carbene [(BIPM)UCl(2)I] (5), and 6 reveal polarized covalent U═C double bonds in each case whose nature is significantly affected by the oxidation state of uranium. Natural Bond Order analyses indicate that upon oxidation from uranium(IV) to (V) to (VI) the uranium contribution to the U═C σ-bond can increase from ca. 18 to 32% and within this component the orbital composition is dominated by 5f character. For the corresponding U═C π-components, the uranium contribution increases from ca. 18 to 26% but then decreases to ca. 24% and is again dominated by 5f contributions. The calculations suggest that as a function of increasing oxidation state of uranium the radial contraction of the valence 5f and 6d orbitals of uranium may outweigh the increased polarizing power of uranium in 6 compared to 5.     

Two Cobalt(II) Complexes Derived from the Hydrolysis Product of Di-Schiff Base Ligand N,N'-Bis-(1-benzimidazo-2-yl-ethylidene)-ethane-1,2-diamine:Preparation,Characterization and Crystal Structure of the 6-Coordinate Species [CoL_2]X·H_2O (X = ClO_4~-, NO_3~-)

The reactions of Co(ClO4)2·6H2O and Co(NO3)2·6H2O with the di-Schiff base ligand N,N'-bis-(1-benzimidazo-2-yl-ethylidene)-ethane-1,2-diamine (LA) in ethanol have been investigated. The reactions of LA with excess amount of cobalt salts yield the six-coordinate complexes [CoL2](ClO4)2·H2O 1 and [CoL2](NO3)2·H2O 2 as isolatable products (L = N-(1-benzimidazo-2-yl-ethylidene)-ethane-1,2-diamine), where L is a tri-dentate mono-Schiff base ligand, resulting from the hydrolysis of the precursor di-Schiff base LA. Both complexes were characterized by X-ray crystallography. Crystal data for complex 1: monoclinic, space group P21/c, a = 11.9214(10), b = 23.5828(17), c = 14.0387(12) , β = 135.219(4)o, C22H30Cl2CoN8O9, Mr = 680.37, V = 2780.1(4) 3, Z = 4, Dc = 1.625 g/cm3, μ(MoKα) = 0.876 mm-1, F(000) = 1404, the final R = 0.0725 and wR = 0.1530 for 5726 observed reflections (I > 2σ(I)). Crystal data for complex 2: monoclinic, space group P21/c, a = 18.2162(16), b = 10.0610(6), c = 18.593(2) , β = 130.099(3)o, C22H30CoN10O7, Mr = 605.49, V = 2606.5(4) 3, Z = 4, Dc = 1.543 g/cm3, μ(MoKα) = 0.722 mm-1, F(000) = 1260, the final R = 0.0619 and wR = 0.1429 for 5194 observed reflections (I > 2σ(I)). X-ray diffraction analysis reveals that each cobalt atom in the two complexes is chelated by six nitrogen atoms from two tridentate ligands L, exhibiting a slightly distorted octahedral coordination sphere. In both complexes, the strong hydrogen-bonding interactions between the lattice waters and N-H groups of the ligands result in 1D chains which are further connected by ClO4-(or NO3-) groups to form a 3D framework. In complex 2, the strong π-π interactions increase the stability of the structure.