Synthesis and structure of a new scorpionate-dithio carboxyl oxovanadium complex and an organic dithio carboxyl compound

A new complex of oxovanadium(IV), V₂O₂[(HB(pz)₃)₂(pyrro)₂ (1) and a dimer-dithio carboxyl compound (C₅H₈NS₂)₂ (2) have been synthesized by the reaction of VOSO₄·nH₂O with NaHB(pz)₃ and pyrrolidine dithio carboxylic acid ammonium salt. They were characterized by element analysis, IR spectra, UV–vis spectra and X-ray diffraction. Structural analyses of 1 and 2 gave the following parameters: 1, triclinic, P-1, a = 7.732(4) Å, b = 14.285(8) Å, c = 17.802(9) Å, α = 101.314(8)°, β = 92.682(9)°, γ = 92.228(9)°, V = 1923.6(18) Å³, and Z = 4; 2, monoclinic, C2/c, a = 13.857(2) Å, b = 10.4213(18) Å, c = 9.436(2) Å, β = 97.099(2), V = 1352.1(4) Å³, and Z = 4. In complex 1, vanadium atom adopts a distorted tetragonal bipyramid structure, which is typical for oxovanadium(IV) complexes. Compound 2 is a dimer-dithio carboxyl compound with S–S bond. In addition, thermal analysis was performed for analyzing the stabilization of the complexes.     

Interaction of chiral bis-distamycin derivatives with DNAs: electronic circular dichroism study

The new diastereomeric complexes of two oligo-N-methylpyrrole peptides, linked by a methano[1,5]-diazocin scaffold with DNA, were prepared. The specificity of the binding modes of (4S,9S)- and (4R,9R)-bis-distamycins derivative with ct-DNA explains the observed optical activity of the racemic mixture of distamycin if DNA is present. The bis-distamycin derivative possesses a clear sequence selectivity for A-T rich sequences of DNA, although a nonspecific binding mode with low affinity was also seen for G-C rich sequences. The reversibility of ECD spectra at 5 °C after heating to 90 °C was established.     

Improved anode performance of thermally treated SiO/C composite with an organic solution mixture

A pristine composite anode material comprising of silicon monoxide and graphite was prepared through ball milling process and made in the form of a slurry using a simple solution mixture consisting of propylene carbonate (PC) and acetone (AC) and then heat treated. Cycle life study of the pristine composite and heat treated organic slurry composite showed the charge capacity values as 318 and 500 mAh g⁻¹, respectively at 100th cycle. Analysis of change of delithiation capacity with cycling and delithiation current between 0.3 and 0.6 V from cyclic voltammogram (CV) along with scanning electron microscope (SEM) and X-ray diffraction (XRD) of the electrodes/composites leads to conclude thermal processing of the organic slurry treated pristine composite converts dispersed active materials of the pristine composite into a compact structure trapped/wrapped with carbon particles (Cx, x varies from 1 to 3) providing apparently a resistor like behaviour and makes the anode deliver a stable reversible capacity with cycling.     

Synthesis and crystal structure of the first chain-type nitridosilicates RE5Si3N9 (RE = La,Ce)

The novel branched chain-type nitridosilicates Ce₅Si₃N₉ and La₅Si₃N₉ have been synthesized in a radio-frequency furnace starting from the respective metals and silicon diimide Si(NH)₂ at 1625 °C for La₅Si₃N₉ and 1650 °C for Ce₅Si₃N₉, respectively. The structure of Ce₅Si₃N₉ has been determined by single-crystal X-ray diffraction (Ce₅Si₃N₉, Cmca (no. 64), a = 10.567(2) Å, b = 11.329(2) Å, c = 15.865(3) Å, V = 1899.3 Å³, Z = 8, R₁ = 0.0391, 1480 independent reflections, 90 refined parameters). The structure of isotypic La₅Si₃N₉ has been refined by the Rietveld method, starting from single-crystal data of Ce₅Si₃N₉ (La₅Si₃N₉, Cmca (no. 64), a = 10.647(4) Å, b = 11.414(4) Å, c = 16.030(5) Å, V = 1948.1 Å³, Z = 8, R_P = 0.0348, R_F² = 0.0533). Both compounds are built up of alternating Q²- and Q³-type corner sharing SiN₄ tetrahedra with additional corner sharing Q¹-units attached to the Q³-tetrahedra pointing alternately in opposing directions. These zipper-like chains are intertwined in both directions perpendicular to the chain itself to form a three-dimensionally interlocked structure with the rare-earth ions situated between the chains. Magnetic measurements resulted in a ferromagnetic ground state with a magnetic moment in agreement with Ce³⁺.     

Distorted perovskite structured organic–inorganic hybrid compounds for possible multiferroic behavior: [n-alkyl]2FeCl4

Perovskite structured compounds have shown multifunctional properties and therefore attracted attention recently because of their potential applications. To explore such materials we have prepared simple double salts, distorted perovskite structured compounds, Cn₂FeCl₄, Cn = n-propyl or n-butyl ammonium ions. (C₃)₂FeCl₄ crystallize in orthorhombic space group, Cmc2₁, having lattice constants a = 7.223(9) Å, b = 7.439(9) Å, c = 25.303(8) Å with unit cell volume of 1359.95 cm³, at room temperature. The overall structure consists of two-dimensional Fe(II)–chloride network, parallel to the ac-plane, interlayered by the ammonium ions. Magnetic measurements using SQUID magnetometer show that these compounds are antiferromagnets with T_N ～ 90 K. Preliminary studies using DSC and AC-conductivity have shown promising transitions above room temperature.     

Syntheses and structures of the MOF-type series of metal 1,4,5,8,-naphthalenetetracarboxylates M2(OH)2[C14O8H4] (Al,Ga, In) with infinite trans-connected M–OH–M chains (MIL-122)

Three new isostructural MOF-type compounds (named MIL-122) have been obtained from the hydrothermal reaction at 210 °C for 24 h of the 1,4,5,8-naphthalenetetracarboxylic acid with aluminum, gallium or indium source in water. The structures of the compounds M₂(OH)₂[C₁₄H₄O₈] (M = Al, Ga, In) have been solved ab initio from powder X-ray diffraction analysis using the synchrotron radiation (Soleil; station CRISTAL). The three-dimensional organic–inorganic framework exhibits infinite straight chains of metal-centered octahedra sharing trans corners linked to each other through the 1,4,5,8-naphthalenetetracarboxylate ligand. The cations Al, Ga or In, are coordinated by four oxygen atoms coming from the carboxyl groups and two bridging hydroxyl groups μ₂-OH, located in trans position in the octahedral surrounding. The compounds characterized by thermogravimetric and thermodiffraction analyses are thermally stable up to 440, 460 and 380 °C, for Al, Ga and In, respectively. Crystal data: monoclinic cell; P2₁/c (n°14); for MIL-122 (Al): a = 9.5174(2), b = 10.0706(1), c = 6.6465(2) Å, β = 91.2614(5)°, V = 636.878(2) Å³, Z = 2; for MIL-122 (Ga): a = 9.6501(1), b = 10.0585(1), c = 6.75069(9) Å, β = 92.4786(9)°, V = 654.65(1) Å³, Z = 2; for MIL-122 (In): a = 9.92359(5), b = 10.19765(7), c = 7.19357(4) Å, β = 727.034(8)°, V = 727.034(8)ų, Z = 2.     

Structure and properties of α-AgFe2(MoO4)3

Silver diiron tris(oxomolybdate), α-AgFe₂(MoO₄)₃, was synthesized in sealed silica tubes at 1050 K and is isostructural to α-NaFe₂(MoO₄)₃, determined by single-crystal X-ray diffraction (space group P?1, a = 6.9320(7) Å, b = 6.9266(6) Å, c = 10.9732(13) Å, α = 81.197(8)°, β = 83.456(9)°, γ = 81.352(8)° at 300 K, Z = 2). The crystal structure is built up from both monomers and edge-sharing dimers of [FeO₆]-octahedra, which are linked with each other by isolated [MoO₄]-tetrahedra to a three-dimensional network. Ag ions are situated on a site with four near oxygen neighbours. Thermal expansion is most pronounced along the c-axis, while the angle α decreases with increasing temperature. Antiferromagnetic ordering is indicated by a sharp maximum in the temperature dependence of magnetization at 21.5(5) K, and a magnetic moment of 5.36(1) μ_B per Fe-ion was derived from the Curie constant in the paramagnetic region. The collinear antiferromagnetic structure with propagation vector k = (0,½,½) and an ordered magnetic moment of 4.62(9) μ_B per Fe-ion were deduced from neutron powder diffraction data and give evidence for an underlying magnetic interaction mechanism, resulting in rather strong and long-ranged couplings. Mössbauer spectroscopy shows a change in the electronic configuration on the two distinct Fe sites between room temperature and 150 K, accompanied by an increase of the average Fe–O distance for one site and a shrinking one for the other as expected for charge ordering in a mixed valence compound with Fe(II) and Fe(III).     

Carbazole-modified blue light-emitting copolymers with the backbones integrated by diphenyloxadiazole,fluorene, and triphenylamine

Two new blue light-emitting polymers, poly{[2,5-bis(4-phenylene)-1,3,4-oxadiazole]-[9,9-dihexylfluorene-2,7-diyl]-[N-(4-(9H-carbazol-9-yl)phenyl)-N,N-bis(p-phenylene)aniline]} (POFPA) and poly{[2,5-bis(4-phenylene)-1,3,4-oxadiazole]-[9,9-dihexylfluorene-2,7-diyl]-[4-(3,6-(di-9H-carbazol-9-yl)-9H-carbazol-9-yl)-N,N-bis(p-phenylene)-aniline]} (POFCPA), were synthesized by Suzuki coupling reactions. By GPC analysis against a linear polystyrene standard POFPA and POFCPA were found to have M_n of 1.68 × 10⁴ and 3.70 × 10³, respectively. In contrast to POFPA, the main absorption peak of POFCPA in dilute toluene solution was blue-shifted by Δλ = 26 nm owing to its backbone of relatively shorter π-conjugation length and more carbazole units in side chain. The absolute fluorescence quantum yield (Φ_f) of POFCPA in dilute toluene solution was determined as 73%, much higher than that of POFPA (Φ_f ≈ 58.9%) measured under the same conditions. An electroluminescence device based on POFCPA displays a stable blue emission having color coordinates of (0.15, 0.20), a maximum brightness of 4762 cd/m², and a maximum current efficiency of 1.79 cd/A. By using this polymer as the host material doped with 1 wt.% 4,4′-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl, the achieved highest brightness, maximum current efficiency and maximum power efficiency are 13,613 cd/m², 3.38 cd/A, and1.84 lm/W, respectively.     

Thiazolylhydrazone dervatives as inhibitors for insect N-acetyl-β-d-hexosaminidase and chitinase

Insect chitinase and N-acetyl-β-d-hexosaminidases (Hex) are potential targets for developing new pesticides. Here, a series of thiazolylhydrazones I (with substituted group R₁ at N3) and II (with substituted group R₁ at N2) were designed, synthesised and evaluated as competitive inhibitors of OfHex1 and OfChi-h, from the agricultural pest Ostrinia furnacalis. Derivatives I-3d and II-3d, with phenoxyethyl group at R₁, demonstrated the best inhibitory activities against OfHex1 and OfChi-h. Molecular docking analysis indicated that the branched conformation compound II-3d (K_i = 1.5 μmol/L) formed more hydrogen bonds with OfHex1 than the stretched conformation compound I-3d (K_i = 5.9 μmol/L). The differences in compounds’ binding conformations with OfChi-h explained differences in inhibitory activity of compounds I-3d (K_i = 1.9 μmol/L) and II-3d (K_i = 4.1 μmol/L). This work suggests a novel scaffold for developing specific Hex and Chi-h inhibitors.     

The experimental and DFT studies of 1,3-dimethyl-2-[4-chloro-styryl]-benzimidazolium iodide

1,3-Dimethyl-2-[4-chloro-styryl]-benzimidazolium iodide (1) was synthesized and characterized by X-ray diffraction, ¹H NMR, MS, IR, UV–vis spectra and elemental analysis. The crystals are monoclinic, space group P2₁/c, with a = 12.507(3) Å, b = 7.3259(19) Å, c = 36.705(9) Å, V = 3358.9(15) Å³, and Z = 4 (at 296(2) K). Crystal stacking scheme indicates the face-to-face π?π aromatic stacking interactions. Molecular geometries, frequencies, IR, ¹H NMR and UV–vis were calculated at DFT/TD-DFT level using two hybrid exchange–correlation functionals, B3LYP and PBE1PBE. The stability of the molecule arising from hyperconjugative interaction and charge delocalization had been analyzed using natural bond orbital (NBO) analysis. These calculations on (1) provide deep insight into its electronic structure and properties.     

Crystal growth of barium rhenates from hydroxide fluxes

Single crystals of two new barium rhenate compositions, Ba₁₆Re₆O₃₇ and Ba₁₀Re₃O₁₆(OH)₃, and of one new polymorph, orthorhombic Ba₅Re₂O₁₂, were grown out of a barium hydroxide flux in sealed silver tubes. Ba₁₆Re₆O₃₇ and Ba₁₀Re₃O₁₆(OH)₃ crystallize into the monoclinic C2/m system, with a = 20.577(4) Å, b = 5.8897(10) Å, c = 15.438 (3) Å, β = 92.255(10) ° and a = 1938342(9) Å, b = 5.8172(3) Å, c = 10.2925(5) Å, β = 91.7460(10) °, respectively. The orthorhombic polymorph of Ba₅Re₂O₁₂ crystallizes in the space group Pnma, with a = 19.6728(10) Å, b = 5.8491(3) Å and c = 10.4648(5) Å. All the three crystal structures are related and consist of a framework of BaO_x polyhedra (where x varies from six to twelve) with interpenetrating layers of ReO₆ octahedra.     

Two metal-organic frameworks with infinite indium hydroxide chains connected through tetradentate carboxylate linkers

Two indium-based metal-organic framework have been hydrothermally synthesized by using 1,2,4,5-benzenetetracarboxylate (pyromellitate) or 3,3′,4,4′-benzophenonetetracarboxylate as linkers. Their structures have been characterized by means of single-crystal X-ray diffraction analysis and reveal closely related networks consisting of identical infinite chains of indium-centered trans-connected octahedra, linked to each other through the tetradentate carboxylate linkers. The structure of the indium pyromellitate (MIL-60) delimits a 3D frameworks with one-dimensional 4.0 × 2.7 Å² channels running along [001] encapsulating water. The second compound (MIL-119) is built up from the compact stacking of the 3,3′,4,4′-benzophenonetetracarboxylate molecules connected to four distinct inorganic chains. In the latter, water species are found to be trapped between two indium hydroxide chains or in terminal positions, bonded to the indium cations. Strong hydrogen interactions are observed between these types of water molecules. Both compounds do not exhibit any significant porosity.Crystal data: In₂(OH)₂[C₁₀O₈H₂]·2H₂O (MIL-60): monoclinic, C2/m, a = 7.1854(7) Å, b = 17.1940(17) Å, c = 6.5167(7) Å, β = 100.639(2)°, V = 791.27(14) Å³, Z = 2. In₂(OH)₂(H₂O)[C₁₇O₉H₆]·H₂O (MIL-119), monoclinic, P2₁/c, a = 14.2530(11) Å, b = 14.4024(10) Å, c = 11.7027(9) Å, β = 93.018(2)°, V = 2399.0(3) Å³, Z = 4.     

Two novel Keggin tungstocobaltates grafted by cobaltII complex group(s): K[Co(phen)2(H2O)]2[HCoW12O40]·2H2O and [Co(2,2′-bipy)3]1.5{[Co(2,2′-bipy)2(H2O)][HCoW12O40]}·0.5H2O

Two novel inorganic–organic hybrid compounds composed of Keggin tungstocobaltate framework and cobalt(II)–N coordination complexes, K[Co(phen)₂(H₂O)]₂[HCoW₁₂O₄₀]·2H₂O (1) (phen = 1,10-phenanthroline) and [Co(2,2′-bipy)₃]_1.5{[Co(2,2′-bipy)₂(H₂O)][HCoW₁₂O₄₀]·0.5H₂O (2) (bipy = bipyridine), have been synthesized under hydrothermal conditions by directly using Keggin POMs as starting materials, which were characterized by elemental analyses, IR, TG analyses and X-ray single crystal diffraction. Crystal data for compound 1: C₄₈H₄₁Co₃KN₈O₄₄W_12, triclinic, space group P-1, a = 10.918(5) Å, b = 13.401(5) Å, c = 13.693(5) Å, α = 69.291(5)°, β = 71.568(5)°, γ = 78.421(5)°, V = 1768.9(12) Å³, Z = 1; for compound 2: C₁₃₀H₁₀₄Co₇N₂₆O₈₃W_24, orthorhombic, space group, C2/c, a = 46.839(9) Å, b = 14.347(3) Å, c = 26.147(5) Å, α = β = γ = 90°, V = 17,570(6) Å³, Z = 4. Compound 1 exhibits a pseudo-1D chainlike structure, in which potassium ions act as linkages of Keggin unit doubly grafted by [Co(phen)₂(H₂O)] complex. Compound 2 represents a [Co(2,2′-bipy)₂(H₂O)]²⁺ mono-grafted Keggin tungstocobaltate derivative with 1.5[Co(2,2′-bipy)₃]²⁺ countercations. The cyclic voltammetric behavior of 1-CPE is similar to the parent 3-CPE, but the cyclic voltammetric behavior of Co^II shows a little difference. Variable-temperature magnetic susceptibility measurement of compound 1 demonstrates the presence of antiferromagnetic interactions.     

Synthesis,thermal behaviour and crystal structure of RbSrP3O9·3 H2O

Rubidium strontium cyclo-triphosphate trihydrate, RbSrP₃O₉·3 H₂O, was synthesized by reaction between cyclo-triphosphoric acid H₃P₃O₉ and rubidium and strontium carbonates. It crystallizes in the othorhombic system, space group Pnma, with a = 9.120(1) Å, b = 8.141(1) Å, c = 15.234(1) Å, V = 1 131.1(3) Å³, Z = 4. Crystal structure determination from single crystal data collected at 300 K shows that the P₃O₉ groups exhibit C_s symmetry and are not connected to each other. Rubidium (distorted octahedron) and strontium (distorted square antiprism) are coordinated by oxygen and water molecules yielding the formation of infinite chains interconnected to each other and to the P₃O₉ groups. The IR valence vibration bands of the P₃O₉ cycle have been identified in the domain 1 400–650 cm^–1 and related to the structural results. After water loss, the anhydrous phase crystallizes from an intermediate amorphous phase and further decomposes into Rb₂SrP₄O₁₂ and SrP₂O₆.     

Spontaneous resolution of a novel chiral coordination polymer through supramolecular interactions and solvent symmetry breaking

The spontaneous resolution reaction of racemic trans-2,3-dihydro-2,3-dipyridyl-benzo[e]indole 1 with Cd(ClO₄)₂·6H₂O in the presence of 2-butanol under solvothermal reaction conditions favors the formation of crystal 2 [P-Cd(R,R,-1)₂(ClO₄)₂], while a similar reaction in the presence of ethanol only favors the formation of crystal 3 [M-Cd(S,S,-1)₂(ClO₄)₂]. The crystal structural determination shows that both 2 and 3 crystallize in chiral enantiomorphous space groups (P6₁22 and P6₅22) and their structures are 1D infinite chain, and are just enantiomorphous pairs most like. The spontaneous resolution process displays estimated ee values of ca. +0.6 for 2-butanol and ca. −0.4 for ethanol. Enantiomerically pure (S,S)-trans-2,3-dihydro-2,3-dipyridyl-benzo[e]indole (S,S,-1) can be obtained through the decomposition of mechanically separated 3. Additionally (S,S,-1) also crystallizes in a chiral space group (P2₁). The CD (circular dichroism) spectra of both 2 and 3 in the solid state are also approximately enantiomorphous pairs. However, their fluorescent spectra in the solid state display a moderate difference in maximum emission peaks (Δλ = 19 nm). Crystal data for 2: C₄₄H₃₄Cl₂N₆O₈Cd, M = 958.07, hexagonal, P6₁22, a = 10.5488(5), c = 68.256(4) Å, α = γ = 90°, β = 120°, V = 6577.8(6) Å³, Z = 6, D_c = 1.451 mg m⁻³, R₁ = 0.0498, wR₂ = 0.1124, μ = 0.679 mm⁻¹, S = 0.623, Flack χ = −0.02(6). For space group P6₅22, R₁ = 0.0670, wR₂ = 0.1602, S = 0.725 with a Flack value of 1.03(7); Crystal data for 3, C₄₄H₃₄Cl₂N₆O₈Cd, M = 958.07, hexagonal, P6₅22, a = 10.5446(3), c = 68.265(3) Å, V = 6573.3(4) Å³, Z = 6, D_c = 1.452 mg m⁻³, R₁ = 0.0444,wR₂ = 0.1002, μ = 0.679 mm⁻¹, S = 0.558, Flack χ = 0.01(5). For space group P6₁22, R₁ = 0.0501, wR₂ = 0.1178, S = 0.599 with a Flack value of 1.00(5). The low Flack parameter indicates that the absolute configurations of 2 and 3 are stated; Crystal data for (S,S)-1, C₂₂H₁₇N₂, M = 323.39, orthorhombic, P2₁2₁2₁, a = 9.2598(7), b = 9.4617(8), c = 19.1452(16) Å, V = 1677.4(2) Å³, Z = 4, D_c = 1.281 mg m⁻³, R₁ = 0.0417, wR₂ = 0.1191, T = 293 K, μ = 0.077 mm⁻¹, S = 0.862.     

Combined experimental and computational study on the energetics of 1,2-benzisothiazol-3(2H)-one and 1,4-benzothiazin-3(2H, 4H)-one

The present work reports an experimental and computational study of the energetics of 1,2-benzisothiazol-3(2H)-one and 1,4-benzothiazin-3(2H, 4H)-one. The standard (p° = 0.1 MPa) massic energy of combustion, at T = 298.15 K, of each compound was measured by rotating bomb combustion calorimetry, in oxygen that allowed the calculation of the respective standard molar enthalpy of formation, in the condensed phase, at T = 298.15 K. The standard molar enthalpies of sublimation, at T = 298.15 K, were measured by high-temperature Calvet microcalorimetry. From the combination of data obtained by both techniques we have calculated the standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K. In addition, computational calculations were carried using the density functional theory with the B3LYP functional and the 6-31G1 basis set and some correlations between structure and energetics were obtained for the keto and enol forms of both compounds. Using the G3(MP2)//B3LYP composite method and various appropriate reactions, the standard molar enthalpies of formation of 1,2-benzisothiazol-3(2H)-one and 1,4-benzothiazin-3(2H, 4H)-one, at T = 298.15 K, were computationally derived and compared with the experimental data. The aromaticity of 1,2-benzisothiazol-3(2H)-one, 1,4-benzothiazin-3(2H, 4H)-one and that of some related species was evaluated by analysis of nucleus independent chemical shifts (NICS).     

Copper and cadmium phosphonates based on 2-quinolinephosphonate

Hydrothermal reactions of 2-quinolinephosphonic acid (1) and CuSO₄ or CdSO₄ result in two new compounds with formula Cu(2-C₉H₆NPO₃) (2) and Cd(2-C₉H₆NPO₃)(H₂O) (3). Compound 2 has a layer structure in which dimers of edge-sharing {CuO₄N} square-pyramids are linked by {CPO₃} tetrahedra through corner sharing. Compound 3 shows a new type of layer structure where chains of corner sharing {CdO₅N} octahedra are connected by {CPO₃} tetrahedra into an inorganic layer. The quinoline groups fill in the inter-layer spaces in both cases. Crystal data for 1: monoclinic, space group P2₁/c, a = 10.270(2) Å, b = 13.566(3) Å, c = 6.9818(16) Å, β = 101.916(4)°, V = 951.8(4) Å³, Z = 4. For 2: monoclinic, space group P2₁/c, a = 13.976(3) Å, b = 7.9398(18) Å, c = 7.8687(18) Å, β = 101.150(5)°, V = 856.7(3) Å³, Z = 4. For 3: monoclinic, space group P2₁/c, a = 17.164(4) Å, b = 5.4870(12) Å, c = 10.850(2) Å, β = 101.557(4)°, V = 1001.1(4) Å³, Z = 4. The magnetic measurement on 2 reveals a dominant antiferromagnetic exchange coupling between the Cu(II) centers. A quasi-reversible electrochemical reaction is observed for complex 2 immobilized on the surface of GC electrode, corresponding to the redox couple Cu²⁺/Cu⁺. The fluorescent properties of 1–3 are also investigated.     

Quantum chemical calculations and X-ray crystallographic studies of cis-dioxomolybdenum(VI) Schiff base complex

Treatment of the Schiff base 2-((E)-(2-hydroxy propylimino)methyl)phenol with MoO₂(acac)₂ in dry methanol gave the mononuclear complex (methanol{6-[(2-oxidopropyl)iminometh-yl]phenolato}dioxidomolybdenum(VI), which was characterized by X-ray crystal analysis, and it has monoclinic space group p2₁/c, and a = 10.330(17) Å, b = 9.397(15) Å, c = 13.695(2) Å, V = 1252.1(3) Å³, and Z = 4. B3LYP theoretical method with DZP basis sets calculations nicely reproduces the X-ray experimental geometry, molecular orbital levels and the other structural properties for this complex.     

Ce(H2O)(PO4)3/2(H3O)1/2(H2O)1/2, a second entry in the structural chemistry of cerium(IV) phosphates

A cerium(IV) phosphate has been prepared using precipitation methods and its structure has been solved by single crystal X-ray diffraction (R₁ = 0.0292 for 3092 reflections with I>2σ(I) and wR₂ = 0.0540). Ce(H₂O)(PO₄)_3/2(H₃O)_1/2(H₂O)_1/2 crystallises in the monoclinic space group C2/c (a = 15.7058(17) Å, b = 9.6261(9) Å, c = 10.1632(4) Å, ß = 121.623(7)°, and V = 1308.4 (2) Å³). Its structure is based on a negatively charged 3D framework, made of cerium atoms connected by PO₄ tetrahedra. There are two types of PO₄ units; one shares only corners with the cerium coordination polyhedra while the other one shares edges and corners. This structure also includes hydronium cations, to balance the framework charge, and water molecules. One special feature of this 3D framework is the formation of interconnected tunnels which extend along the c axis and contain the hydronium cations and the water molecules. This open framework and the presence of cationic species in the tunnels are in perfect agreement with the previously reported ion exchange properties.     

Syntheses,structures and single-molecule magnetic behaviors of two dicubane Mn4 complexes

The reaction of MnX₂ · 4H₂O (X = Cl or Br) with 2,6-bis(hydroxymethyl)-4-methylphenol (H₃L) and NaOH in methanol solution yielded two tetranuclear manganese complexes, [Mn₄(HL)₄(MeOH)₄Cl₂] (1) and [Mn₄(HL)₄(MeOH)₄Br₂] (2). Both compounds crystallize in the monoclinic space group C₂/c with cell parameters: a = 26.0945(19) Å, b = 11.4999(8) Å, c = 21.2188(16) Å, β = 121.050(1)° and z = 4 for 1 · 2Et₂O; a = 25.8145(3) Å, b = 11.6734(2) Å, c = 21.3956(3) Å, β = 120.1277(6)° and z = 4 for 2 · 2Et₂O. Both complexes consist of a mixed-valence dicubane structure, which comprises two Mn^II and two Mn^III ions. Magnetic susceptibilities and magnetization of complexes 1 and 2 in the solid state indicate that two clusters have an S = 9 ground state. Frequency-dependent out-of-phase signals of alternating current magnetic susceptibilities were observed in the low temperature range (<3 K) for both complexes indicating a slow magnetic relaxation.