Synthesis,Structure and Physical Properties of an Hybrid Compound Based on Strandberg Type Polyoxoanions and Copper Cations

Single crystals of novel Strandberg type molybdophosphonate complex, (C₅H₇N₂)₆[Cu(H₂O)₃HP₂Mo₅O₂₃]₂·4H₂O, are synthesized in aqueous solution and characterized by X-ray diffraction, spectroscopy (diffuse reflectance, UV–Vis and IR) and thermal analysis. Single crystal X-ray diffraction analysis reveals that this novel compound is composed of [Cu(H₂O)₃HP₂Mo₅O₂₃]^3? anions, three distinct 2-aminopyridinium cations as counter-ions and two distinct crystallization water molecules. The crystal packing is stabilized by H-bonds and π–π interactions, resulting in a 3D framework. In addition, the magnetic behavior of the related compound is measured. Magnetic measurements from 100 to 2 K indicate the presence of an antiferromagnetic coupling between the Cu (II) ions in (C₅H₇N₂)₆[Cu(H₂O)₃HP₂Mo₅O₂₃]₂·4H₂O complex, resulting in a maximum of an antiferromagnetic–paramagnetic transition at T_N = 7 K. Magnetic susceptibility data indicate an antiferromagnetic Curie–Weiss behavior in the studied temperature range, and molecular field theory gives the (J/k_B) values of the nearest neighbor interactions between copper ions.     

Heteropolymolybdate–amino acid complexes: synthesis,characterization and biological activity

Three Keggin-type polyoxometalates functionalized by amino acids, (C₅H₁₃N₂O₂)₂(H₃O)PMo₁₂O₄₀·8H₂O 1, (C₅H₁₄N₂O₂)₂SiMo₁₂O₄₀·12H₂O 2 and (C₅H₁₄N₂O₂)₂GeMo₁₂O₄₀·12H₂O 3, were synthesized and characterized by elemental analysis, IR and ¹H?NMR spectra and single-crystal X-ray diffraction. The X-ray crystallographic study showed that the structures of the three compounds involved N–H···O and O–H···O hydrogen bonds among the protonated ornithine cations, water molecules and the heteropolyanion cluster, and thus represent a model interaction between polyoxometalates and proteins. These complexes display inhibitory actions to the human cancer cells Hela and PC-3?m in vitro.     

Synthesis and Crystal Structure of 4-Aminoquinolinium Dicitratoborate Monohydrate

4-Aminoquinolinium dicitratoborate monohydrate [(4-NH₂)C₉H₆NH][(C₆H₆O₇)₂B] · H₂O (I) has been synthesized for the first time. Single crystals have been studied by X-ray crystallography. The structural units of crystal I are large complex dicitratoborate anions with a spirane structure, 4-aminoquinolinium cations and crystal water molecules. The crystal packing of I is three-dimensional. Seventeen independent contacts O(N)-H?O and N-H?O,O’ form an intricate system of hydrogen bonds.     

New Borate‐citrate: Synthesis,Structure, and Properties of Sr[B(C6H5O7)2](H2O)4·3H2O

Single crystals of Sr[B(C₆H₅O₇)₂](H₂O)₄ · 3H₂O, a new borate‐citrate material, were grown with sizes up to 8 × 6 × 2 mm by slow evaporation of water at room temperature. The structure of Sr[B(C₆H₅O₇)₂](H₂O)₄ · 3H₂O was determined by single‐crystal X‐ray diffraction. It crystallizes in the monoclinic space group P2₁/c, with a = 11.363(3) Å, b = 18.829(4) Å, c = 11.976(3) Å, β = 110.736(3)°, and Z = 4. The SrO₈ dodecahedra, BO₄ tetrahedra and citrate groups are linked together to form chains. The compound was characterized by IR and UV/Vis/NIR transmittance spectroscopy as well as thermal analysis.     

Study of the Dehydration/Rehydration of Ammonium Tris-Oxalato Aluminate(III) (NH4)3Al(C2O4)3⋅3H2O at Controlled Atmosphere

The study of the dehydration/rehydration of ammonium tris-oxalato aluminate(III) (NH₄)₃Al(C₂O₄)₃⋅3H₂O in flowing dinitrogen saturated with water vapor at room temperature, using thermogravimetric analysis and X-ray diffraction techniques, allowed the determination of the temperature stability domains of (NH₄)₃Al(C₂O₄)₃⋅3H₂O, (NH₄)₃Al(C₂O₄)₃⋅2H₂O and the anhydrous salt. The X-ray powder diffraction profiles are reported for each of the three phases. This revised version was published online in August 2006 with corrections to the Cover Date.     

Two W/Mo complexes containing 2,3-dihydroxynaphthalene: synthesis and structure analysis

Two W/Mo complexes, [Et₃NH]₂[WO₂(C₁₀H₆O₂)₂] (1) and [Et₃NH]₂[MoO₂(C₁₀H₆O₂)₂] (2), were synthesized by the reaction of Na₂WO₄?·?2H₂O and (NH₄)₂Mo₂O₇?·?4H₂O with 2,3-DHN (DHN?=?dihydroxynaphthalene) and triethylamine, and characterized by X-ray diffraction and IR. The two complexes exhibit chiral octahedral geometry at central metals, although the overall structure is racemic. Single crystals of 1 are more difficult to obtain than for 2. The molybdenum complex can be easily isolated at room temperature (around 25°C), while the tungsten one needs to be isolated under 15°C, otherwise, the quality of crystal will be poor, leading to disorder. The structures of these two complexes are chiral and enantiomorphous to each other.     

Komplexe mit substituierten 2,5-Dihydroxy-p-benzochinonen: EAC6(C6H5)2O4 · 4 H2O (EA = Sr2+, Ba2+)

Complexes with Substituted 2,5-Dihydroxy-p-benzochinones: EAC₆(C₆H₅)₂O₄ · 4 H₂O (EA = Sr²⁺, Ba²⁺) Single crystals of the isotypic compounds EAC₆(C₆H₅)₂O₄ · 4 H₂O were grown in aqueous silicagel. EA²⁺ has CN 8. It is surrounded by four water molecules and four oxygen atoms of the bis-chelating polyporate dianions. Thereby folded chains are formed which are interlinked by hydrogen bonds. Thus building up corrugated layers with the phenyl substituents almost perpendicular to the layer plane. The layer stacking provides that they can engage into another.     

Two compounds constructed from Strandberg-type polyoxoanions,metals and organic ligands

Two new hybrid compounds, [Cu(1)(phen)(H₂O)][Cu(2)(phen)(H₂O)]([Cu(3)]_0.25(H₂O)][P₂Mo₅O₂₃]·3.75H₂O (1) and [Cu(en)₂]_1.5[P₂Mo₅O₂₃]₂·(enH₂)₃·2H₂O (2) (phen = 1,10-phenanthroline, en = ethylenediamine), have been hydrothermally synthesized and characterized by IR, UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), powder XRD analyses, TG analyses, cyclic voltammogram analyses, elemental analyses, and single crystal X-ray diffraction analyses. Single crystal X-ray diffraction analyses reveal that the two compounds have a 1-D chain structure formed by Strandberg-type POMs and TMCs with –A–B–C–B–A–B–C–B– linking mode, then further extend into a 2-D layer structure through π?π or hydrogen bond interactions.     

草酸铕颗粒微米层状颗粒的合成及其光学性能

Hierarchical europium oxalate Eu₂(C₂O₄)₃·10H₂O micro-particles were synthesized through a simple precipitation method at room temperature in present of trisodium citrate. The prod-ucts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and photoluminescence. The possible formation mechanism of the hierarchical europium oxalate Eu₂(C₂O₄)₃·10H₂O micro-particles was discussed.     

Two tris(oxalato)ferrate(III) hybrid salts with pyridinium derivative isomers as counter cations: synthesis,crystal structures,thermal analyses,and magnetic properties

Two organic–inorganic hybrid salts, tris(2-amino-4,6-dimethylpyridinium) tris(oxalato)ferrate(III), (C₇H₁₁N₂)₃[Fe(C₂O₄)₃] (1), and tris(4-dimethylaminopyridinium) tris(oxalato)ferrate(III) tetrahydrate, (C₇H₁₁N₂)₃[Fe(C₂O₄)₃]·4H₂O (2), have been synthesized and characterized by elemental and thermal analyses, IR spectroscopy, single-crystal X-ray diffraction, and SQUID magnetometry. Compounds 1 and 2 crystallize in triclinic P-1 and monoclinic C2/c space groups, respectively. Each compound contains the anionic complex [Fe(C₂O₄)₃]^3- in which the central metal is six-coordinate in a slightly distorted octahedron defined by three chelating oxalate(2-) ligands. The two substituted pyridinium cations are isomers. However, due to the great steric hindrance provided by the bulky cation, 2-amino-4,6-dimethylpyridinium, only the 4-dimethylaminopyridinium cation, the smallest of this series, led to formation of 2 with enough vacant spaces to be occupied by four solvent water molecules. In the crystals, cations and anions are connected via hydrogen-bonds of the types N–H?O in 1 and N–H?O and O–H?O in 2, with π–π stacking interactions between the pyridine rings stabilizing the 3-D framework. The thermal studies confirmed the anhydrous character of salt 1 and the presence of water molecules in salt 2. The magnetic susceptibility measurements in the 2–300 K temperature range revealed weak antiferromagnetic coupling in the two salts.     

Synthesis,growth, structure and characterization of nickel(II)-doped hexaaquacobalt(II) dipotassium tetrahydrogen tetra-o-phthalate tetrahydrate crystals

Single crystals of K₂[Co_(1−x)Ni_x(H₂O)₆] (C₈H₅O₄)₄·4H₂O (x = 0.25) (PCNHP), a semiorganic black colored transparent crystal of size ∼20 × 13 × 4 mm³, are grown from an aqueous solution of potassium hydrogen phthalate enriched with cobalt chloride and nickel chloride by slow evaporation solution growth technique at room temperature. Structural analysis by single crystal X-ray diffraction reveals that the crystal belongs to monoclinic system with space group P2₁/c and the cell parameters are a = 10.41(3) Å, b = 6.84(2) Å, c = 29.46(9) Å, Z = 4. Incorporation of both Co(II) and Ni(II) into the potassium hydrogen phthalate (KHP) crystal lattice is well confirmed by EDS and chemical tests. Powder XRD profiles indicate the crystallinity and FT-IR studies reveal the vibrational patterns. The UV–vis optical absorption spectrum of PCNHP shows the lower optical cut-off at ∼300 nm and the crystal was transparent in the entire visible region. The crystalline perfection of the grown crystal analysed by high-resolution X-ray diffraction (HRXRD) analysis reveals that the diffraction curve (DC) contains multi-peaks with low angular spread indicating the possibility of low angle structural grain boundaries. Scanning electron microscope (SEM) studies indicate the structure defect centers. The dielectric, thermal and mechanical behaviors of the specimen were also investigated.     

Crystal structure,vibrational studies,optical properties,and Hirshfeld surface analysis of (C5H6N5)2[Cr2O7]

Single crystals of a new organic–inorganic compound, (C₅H₆N₅)₂Cr₂O₇ (1), adeninium dichromate, were grown by the slow evaporation technique and characterized by X-ray diffraction, infrared absorption, and the optical properties were also investigated by UV-vis absorption spectroscopy. The compound crystallizes in the triclinic system and P-1 space group with a = 11.6850(2) Å, b = 11.7531(5) Å, c = 14.5603(7) Å, α = 83.956(3)°, β = 70.481(4)°, γ = 61.863(2)°, V = 1658.70(12) Å³. The structure of the compound consists of four adeninium, (C₅H₅N₂)⁺, cations, and two dichromate dianions with all the atoms situated in general positions. Each dichromate anion is formed by two tetrahedral CrO₄ joined through shared O atoms and are linked to the cations with several weak hydrogen bonding interactions resulting in an extended network. 3-D Hirshfeld surface analysis and 2-D fingerprint plots indicate that the packing is dominated by H?O/O?H and H?N/N?H contacts.     

Mechanochemical Synthesis and Characterization of Alkaline Earth Metal Terephthalates: M(C8H4O4)·nH2O (M = Ca,Sr, Ba)

The mechanochemical synthesis offers an easy access to obtain alkaline earth metal terephthalates M(C₈H₄O₄) · nH₂O (M = Ca, Sr, Ba). In the presented study we describe for the first time the mechanochemical synthesis of powders of Ca(C₈H₄O₄) · 3H₂O, Ca(C₈H₄O₄), Sr(C₈H₄O₄) · H₂O, and Ba(C₈H₄O₄), which so far were only synthesized as single crystals from aqueous solutions or by reactions in an autoclave. Furthermore, a new hydrate Ba(C₈H₄O₄) · 2(1.5)H₂O, not described so far in the literature, was prepared. All compounds were characterized by X‐ray powder diffraction, thermal analysis, elemental analysis, FT‐IR, and MAS NMR spectroscopic measurements.     

Copper(II) complexes based on 2-thenoyltrifluoroacetone aroyl hydrazones: Synthesis,spectroscopy, and X-ray diffraction analysis

Copper(II) complexes CuL ? NH₃ are synthesized by the interaction of ethanol solutions of parasubstituted 2-thenoyltrifluoroacetylmethane aroyl hydrazones (H₂L¹–H₂L⁴) and an aqueous-ammonia solution of copper(II) acetate in an equimolar ratio. The copper(II) complexes are studied by elemental analysis, IR spectroscopy, and EPR spectroscopy. Single crystals of CuL³ ? NH₃ are grown from 1-(2-thenoyl)- 3,3,3-trifluoroacetone para-methylbenzoyl hydrazone and studied using X-ray diffraction analysis (CIF file CCDC 1045841).     

Onium salts of sulfur-containing oxyanions resulting from reaction of sulfur(IV) oxide with aqueous solutions of 1,2-diamines and morpholine

Reaction products have been isolated from SO₂–L–H₂O–О2 systems (L = ethylenediamine, N,N,N′,N′-tetramethylethylenediamine, piperazine, and morpholine) as onium salts [H₃NCH₂CH₂NH₃]SO₄, [(CH₃)₂NHCH₂CH₂NH(CH₃)₂]SO₄, [(CH₃)₂NHCH₂CH₂NH(CH₃)₂]S₂O₆ ? H₂O, [C₄H₈N₂H₄]SO₃ ? H₂O, [C₄H₈N₂H₄]S₂O₆, [C₄H₈N₂H₄]SO₄ ? H₂O, [O(C₂H₄)₂NH₂]₂SO₄ ? H₂O. The prepared compounds have been characterized by X-ray diffraction analysis, X-ray powder diffraction, IR and mass spectroscopy.     

Two new polyoxometalate-based organic-inorganic hybrids: synthesis,crystal structure and characterization

Two new organic-inorganic hybrids, (4,4′-bipy)[Cu^I(2,2′-bipy)₂]₂[W₆O₁₉] (2,2′-bipy = 2,2′-bipyrine, 4,4′-bipy = 4,4′-bipyrine) (1) and (C₆H₅NO₂)₄{Mn^III(H₂O)}[As^IIIW₉O₃₃]₂{W(OH)}- {W(H₂O)}?～18H₂O (2), have been synthesized and characterized by elemental analysis, IR, TG, UV–Vis, XRPD, XPS, electrochemical analysis and single-crystal X-ray diffraction. Single crystal X-ray diffraction analysis shows that 1 is a new Lindqvist-type polyoxoanion bisupported by copper(I) coordination cations and 2,2′-bipy ligands and exhibits a three-dimensional (3-D) supermolecular framework by aromatic π–π stacking interactions. Compound 2 is constructed from a manganese(III)-substituted sandwich-type polyoxoanion based on [α-AsW₉O₃₃]^9? units and dissociative, protonated pyridine-4-carboxylic acid molecules, which act as the charge compensation cations. The cyclic voltammogram of 2 shows an irreversible redox process for Mn³⁺ ions.     

Crystal structure of 1-cyclohexylpiperazine-1,4-diium dichromate(VI)

Single crystals of 1-cyclohexylpiperazine-1,4-diium dichromate(VI), (C₁₀H₂₂N₂)[Cr₂O₇], were obtained by slow evaporation at room temperature from an aqueous solution of potassium dichromate, hydrochloric acid and 1-cyclohexylpiperazine. (C₁₀H₂₂N₂)[Cr₂O₇] is triclinic (P\(\bar 1\)) with a = 10.351(2) Å, b = 12.766(3) Å, c = 6.111(1) Å, α = 91.50(2)°, β = 104.26(3)°, γ = 94.91(2)°, V = 778.8(3) ų, and Z = 2. The structure determination performed from single crystal X-ray diffraction data leads to R₁/wR₂ reliability factors of 0.032/0.078. The asymmetric unit of the title salt C₁₀H₂₂N₂²⁺·Cr₂O₇^2?, consists of one 1-cyclohexylpiperazine-1,4-diium dication and one dichromate dianion. These entities are linked together by N–H···O hydrogen bonds to form {(C₁₀H₂₂N₂)[Cr₂O₇]}_n infinite chains lying parallel to the (100) plane and running along the c axis. The intermolecular N–H···O hydrogen bonds link these chains into a two-dimensional network structure consolidated through C–H···O weak interactions.     

Chloro-free route to mixed-metal oxides. Synthesis of lead titanate nanoparticles from a single-source precursor route

A new heterobimetallic nitrilotriacetatoperoxotitanate complex of titanium and lead [Pb(H₂O)₃]₂[Ti₂(O₂)₂O(nta)₂]·4H₂O (C₆H₆O₆N=H₃nta) was isolated in pure crystals directly from the solution containing tetrabutyl orthotitanate, hydrogen peroxoide, lead acetate, and nitrilotriacetic acid at pH = 2.0–4.0. The isolated complex was characterized by elemental analyses, IR spectrum, thermal analysis (TG), and single-crystal X-ray diffraction. The single-crystal X-ray structural analysis revealed that the titanium atom is N,O,O′,O′′-chelated by the nitrilotriacetate and O,O′-chelated by the peroxo group and was coordinated to the bridging O atom in an overall pentagonal-bipyramidal geometry. The thermal decomposition of this precursor led to the formation of phase-pure lead titanate (PbTiO₃) at ≥450 °C. The morphology, microstructure, and crystalline of the resulting PbTiO₃ product have been characterized by BET, transmission electron microscopy, and powder X-ray diffraction. The TEM micrographs revealed that the size of the as-synthesized crystallines to be 50–100 nm range. The BET measurement revealed that the PbTiO₃ powders had a surface area of 5.6 m²/g.     

Uranyl complexes with methyl derivatives of alicyclic dioximes

A reaction of uranyl dioxalate complexes with methyl derivatives of alicyclic ??-dioximes, 3-methyl-1,2-cyclohexanedione dioxime and 3-methyl-1,2-cyclopentanedione dioxime, was studied. The structure of (CN₃H₆)₄[(UO₂)₂(C₆H₈N₂O₂)(CO₃)(C₂O₄)₂] · (C₆H₁₀N₂O₂) · 2H₂O and NH₄(CN₃H₆)₃[(UO₂)₂(C₇H₁₀N₂O₂)(CO₃)(C₂O₄)₂] · 2H₂O based on binuclear complex anions with carbonate-dioximate fragment was studied by X-ray diffraction.     

Synthesis of Thiocyameluric Acid C6N7S3H3, Its Reaction to Alkali Metal Thiocyamelurates and Organic Tris(dithio)cyamelurates

Thiocyameluric acid C₆N₇S₃H₃, the tri-thio analogue of cyameluric acid, is a key compound for the synthesis of new s-heptazine (tri-s-triazine) derivatives. Here, two different routes for the synthesis of thiocyameluric acid and its reaction to tris(aryldithio)- and tris(alkyldithio)cyamelurates C₆N₇(SSR)₃ are reported as well as transformation to alkali metal thiocyamelurates M₃[C₆N₇S₃], M=Na, K. These compounds were characterised by FTIR, Raman, solution ¹³C and ¹H NMR spectroscopies, thermal gravimetric analysis (TGA) and elemental analysis. The three (de)protonation steps of thiocyameluric acid were investigated by acid–base titration followed via UV/Vis absorption spectroscopy. While it was not possible to determine the three pK_a values, it could be postulated that the acid strength probably increases in the following order: cyanuric acid (C₃N₃O₃H₃) < thiocyanuric acid (C₃N₃S₃H₃) < cyameluric acid (C₆N₇O₃H₃) < thiocyameluric acid (C₆N₇S₃H₃). Single crystals of Na₃[C₆N₇S₃]⋅10 H₂O and K₃[C₆N₇S₃]⋅6 H₂O were obtained and the structures analyzed by single crystal X-ray diffraction. Additionally, quantum chemical calculations were performed to get insights into the electronic structure of thiocyameluric acid and to clarify the thiol–thione tautomerism. Based on a comparison of calculated and measured vibrational spectra it can be concluded that thiocyameluric acid and the di- and mono-protonated anions exist in the thione form.