Hydrothermal Synthesis,Crystal Structures and Characterization of Two Hydrogen Phosphates Templated by 4-Amino-2,2,6,6-tetramethylpiperidine

Abstract

Chemical preparations, crystal structures, thermal analyses, and IR spectroscopic studies are given for two new hydrogen phosphates templated by 4-amino-2,2,6,6-tetramethylpiperidine: (C₉H₂₂N₂)₂·(H₂PO₄)·(HPO₄)·(F)·H₂O (I) and (C₉H₂₂N₂)·(H₂PO₄)₂(II). The structures are determined by single crystal X-ray diffraction. Both compounds crystallize in the P2₁/c (N°14) monoclinic space group with the unit cell parameters: a = 14.856 (1) Å, b = 14.092 (2) Å, c = 14.7166 (9) Å, β = 118.434 (7)°, V = 2709.2 (4) Å ³, and Z = 4 for (I) and a = 9.803 (2) Å, c = 0.466 (2) Å, c = 15.640 (8) Å, β = 94.990 (4), V = 1598.68 (7) ų, and Z = 4 for (II).

The structure of I, refined to R = 0.042 and R_w = 0.067 for 6009 reflections (I ≥ 2σ (I)), exhibits infinite inorganic chains _∞((H₂PO₄)·(HPO₄)·(F)·H₂O)^4? linked together through weak hydrogen bonds to form layers onto which the diprotonated [C₉H₂₂N₂]^{2 +} amine molecules are anchored.

The structure of II, refined to R = 0.060 and R_w = 0.086 for 1435 reflections (I ≥ 2σ (I)), consists of _∞(H₂PO₄)^? (100) layers between which [C₉H₂₂N₂]²⁺ cations are inserted. A network of hydrogen bonds connects the different components. IR spectra of I and II show the characteristic bands of amine groups and phosphate anions.     

Analytical applications of the reaction of thorium with benzenephosphonic acid

Benzenephosphonic acid quantitatively precipitates thorium as Th(C₆H₅PO₃)₂·3H₂O at pH values as low as 0.5. The compound may be dried at 140° to 180° C and weighed, as a gravimetric means of determining thorium. On ignition, Th (C₂H₅PO₃)₂ 3 H₂O undergoes decomposition at 240° to 300° C to form Th(C₆H₅PO₃)₂·2H₂O, at 450° to 650° C to form Th(HPO₄)₂·2H₂O and finally at 800° to 1000° C to form Th(HPO₄)₂. The latter compound is stable to 1200° C.Potentiometrically (pK₁' = 0.91, pK₂' = 6.41) and spectrophotometrically (pK₁' = 0.96, pK₂' = 6.51) determined pK' values are reported. Absorption spectra of C₆H₅PO₃H₂, C₆H₅PO₃H^- and C₆H₅PO₃^-2 are reported. The solubility of Th (C₆H₅PO₃)₂·3H₂O was studied as a function of pH and the average value of the solubility product (K_sp = 4s³) was found to be 3.24·10^-31.     

Arrhenius constants for the reactions of ozone with ethylene and acetylene

The kinetics of ozonation of C₂H₄ and C₂H₂ have been studied in the gas phase from ?40 to ?95°C (C₂H₄) and +10 to ?30°C (C₂H₂). The O₃ concentrations were near 10^?4 M, and the hydrocarbons were present in 2- to 25-fold excess. A few experiments with propylene were also carried out. The reactions were followed by observing the rate of decay of O₃ absorption at 2537 Å. Reaction stoichiometries and effects of added O₂ were investigated. The second-order rate constant for C₂H₄ was log k(M^?1 sec^?1) = (6.3 ± 0.2) – (4.7 ± 0.2)/θ (θ = 2.3RT). The rate was independent of the presence of excess O₂. Rate measurements for C₃H₆ were less accurate because of aerosol interference. Combined with room temperature measurements of other workers, the C₃H₆ rate constant was log k(M^?1 sec^?1) = (6.0 ± 0.4) – (3.2 ± 0.6)/θ. The C₂H₂ rate constant was log k(M^?1 sec^?1) = (9.5 ± 0.4) – (10.8 ± 0.4)/θ. In the case of C₃H₆ the major product was propylene ozonide. Ethylene did not yield the ozonide, and the products of the O₃–C₂H₄ and O₃–C₂H₂ reactions were not identified. Pre-exponential factors for the olefin reactions are consistent with a five-membered ring transition state formed by 1,3 dipolar cycloaddition of O₃. For C₂H₂, however, the much higher observed A factor suggests a different mechanism. Possible transition states for the O₃–C₂H₂ reaction are discussed.     

Crystal structure,luminescence, and thermochromic properties of bis(tetraethylammonium) hexabromotellurate(IV)

The atomic structure of ((C₂H₅)₄N)₂TeBr₆ crystals (a = 17.930(8) Å, b = 11.133(5) Å, c = 15.022(7) Å, β = 109.28(9)°, space group C2/c, Z = 4, ρ_calcd = 2.036 g/cm³) has been studied by X-ray diffraction. The ((C₂H₅)₄N)₂TeBr₆ crystal structure consists of isolated [TeBr₆]^2? anions and ((C₂H₅)₄N)⁺ cations. The electronic and geometric aspects that influence the luminescence and thermochromic properties of the complex have been considered.     

Thermodynamic properties of crystalline phosphate Ba0.5Zr2(PO4)3 over the temperature range from T → 0 to 610 K

The temperature dependence of the heat capacity of crystalline barium zirconium phosphate C _p ^o  = f(T) was measured over the temperature range 6–612 K. The experimental data obtained were used to calculate the standard thermodynamic functions C _p ^o (T), H°(T) ? H°(0), S°(T), G°(T) ? H°(0) over the temperature range from T → 0 to 610 K and standard entropy of formation at 298.15 K. The data on the low-temperature (6 ≤ T/K ≤ 50) heat capacity were used to determine the fractal dimension of Ba_0.5Zr₂(PO₄)₃. Conclusions concerning the topology of the structure of phosphate were drawn. Thermodynamic properties of M_0.5Zr₂(PO₄)₃ (M = Ca, Sr, Ba) were compared.     

Synthese und Kristallstruktur von K2(HSO4)(H2PO4), K4(HSO4)3(H2PO4) und Na(HSO4)(H3PO4)

Synthesis and Crystal Structure of K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄), and Na(HSO₄)(H₃PO₄) Mixed hydrogen sulfate phosphates K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄) and Na(HSO₄)(H₃PO₄) were synthesized and characterized by X‐ray single crystal analysis. In case of K₂(HSO₄)(H₂PO₄) neutron powder diffraction was used additionally. For this compound an unknown supercell was found. According to X‐ray crystal structure analysis, the compounds have the following crystal data: K₂(HSO₄)(H₂PO₄) (T = 298 K), monoclinic, space group P 2₁/c, a = 11.150(4) Å, b = 7.371(2) Å, c = 9.436(3) Å, β = 92.29(3)°, V = 774.9(4) ų, Z = 4, R₁ = 0.039; K₄(HSO₄)₃(H₂PO₄) (T = 298 K), triclinic, space group P 1, a = 7.217(8) Å, b = 7.521(9) Å, c = 7.574(8) Å, α = 71.52(1)°, β = 88.28(1)°, γ = 86.20(1)°, V = 389.1(8)ų, Z = 1, R₁ = 0.031; Na(HSO₄)(H₃PO₄) (T = 298 K), monoclinic, space group P 2₁, a = 5.449(1) Å, b = 6.832(1) Å, c = 8.718(2) Å, β = 95.88(3)°, V = 322.8(1) ų, Z = 2, R₁ = 0,032. The metal atoms are coordinated by 8 or 9 oxygen atoms. The structure of K₂(HSO₄)(H₂PO₄) is characterized by hydrogen bonded chains of mixed H_nS/PO₄^– tetrahedra. In the structure of K₄(HSO₄)₃(H₂PO₄), there are dimers of H_nS/PO₄^– tetrahedra, which are further connected to chains. Additional HSO₄^– tetrahedra are linked to these chains. In the structure of Na(HSO₄)(H₃PO₄) the HSO₄^– tetrahedra and H₃PO₄ molecules form layers by hydrogen bonds.     

Über Kondensierte Phosphate des Melamins

Condensed Phosphates of Melamine The title compounds with the formulae (C₃H₆N₆)_n · H_n+2P_nO_3n+1 (linear phosphates, n = 2; 3) and (C₃H₆N₆ · HOP₃)_m (cyclic phosphates, m = 3; 4; 6; 8 and high polymeric phosphate) are obtained as crystalline hydrates by interaction of the corresponding sodium phosphates with stoichiometric amounts of melamine hydrochloride and hydrochloric acid or melamine hydrochloride in aqueous solution. With the exception of (C₃H₆N₆ · HPO₃)₄ · 6H₂O ( I ) these hydrates decompose at ～100°C forming a mixture of mono and diphosphate which transforms at ～200°C into pure melamine diphosphate and at ～250°C into melamine polyphosphate. In contrast to this I froms at ～100°C the anhydrous melamine tetrametaphosphate which converts at ～150°C into melamine polyphosphate. Melamine diphosphate and polyphosphate are also formed on heating melamine monophosphate C₃H₆N₆ · H₃PO₄.     

Über Chalkogenolate. 152. Untersuchungen über Derivate der N-Thioformyldithiocarbamidsäure. 2. Kristallstruktur von Tetra-n-butylammonium-N-thioformyldithiocarbamat

On Chalcogenolates. 152. Studies on Derivatives of N-Thioformyl Dithiocarbamic Acid. 2. Crystal Structure of Tetra-n-butylammonium N-Thioformyl Dithiocarbamate The title compound [N(ⁿC₄H₉)₄][S₂C? NH? CS? H] crystallizes with Z = 2 in the triclinic space group P1 with cell dimensions a = 9.694(2) Å, b = 11.478(3) Å, c = 12.551(6) Å, α = 63.03(3)°, β = 66.42(2)°, γ = 85.60(2)°. The crystal structure has been determined from single crystal X-ray data measured at 20°C and refined to a conventional R of 0.061 for 2249 independent reflections (R_w = 0.042). The structure is built up of dimeric aggregates consisting of 2[N(ⁿC₄H₉)₄]⁺ cations and 2[S₂C? NH? CS? H]^? anions. The two anions are linked together by ? CS? S…?H? N bridges. To make possible a space saving stacking of the dimeric aggregates in the crystal, one methyl group in terminal position of one n-butyl chain in the cation has gauche conformation.     

Beiträge zur Kristallchemie und zum thermischen Verhalten von wasserfreien Phosphaten. XXXXII Die ersten Iridiumphosphate

The First Iridiumphosphates Two polymorphs of iridium(III)‐metaphosphate Ir(PO₃)₃ and an iridium(IV)‐silicophosphate (Ir_1?xSi_x)₃[Si₂O(PO₄)₆] (x ～ 0.5) were synthesized and their crystal structures determined from single‐crystal x‐ray data. Pale pink needles of triclinic Ir(PO₃)₃ (Ru(PO₃)₃ structure type, (No. 2), Z = 2, a = 6.9574(6) Å, b = 10.3628(9) Å, c = 5.0288(4) Å, α = 92.28(1)°, β = 92.80(1)°, γ = 98.60(1)°, 1574 independent reflections, 122 parameters, R₁ = 0.028, wR₂ = 0.061) were grown from a metaphosphoric acid melt. Pale pink prisms of C‐type Ir(PO₃)₃ (C‐Al(PO₃)₃ structure type, Cc (No. 14), Z = 12, a = 13.103(2) Å, b = 19.183(1) Å, c = 9.354(1) Å, β = 127.19(1)°, 4254 independent reflections, 354 parameter, R₁ = 0.024, wR₂ = 0.062) were obtained by chemical vapour transport (900 °C → 800 °C, addition of IrCl₃·xH₂O). Both metaphosphates are built of [Ir^IIIO₆] octahedra and infinite chains. The latter have a translation period of three phosphate tetrahedra in the triclinic modification and six in the monoclinic. 1D and double‐quantum filtered 2D ³¹P‐MAS‐NMR spectra of C‐type Ir(PO₃)₃ confirm the chain structure and reveal a chemical shift range between ?4,8 and ?30,9 ppm for the 9 crystallographically independent, however chemically similar phosphate groups. Pale orange crystals of (Ir_1?xSi_x)₃[Si₂O(PO₄)₆] (Si₃[Si₂O(PO₄)₆] structure type, (No. 148), Z = 3, a = 7.8819(8) Å, c = 24.476(4) Å, 1086 independent reflections, 56 parameters, R₁ = 0.061, wR₂ = 0.190) occurred in chemical vapour transport experiments aiming at the crystallization of C‐Ir(PO₃)₃. The crystal structure of the silicophosphate consists of isolated [Ir^IVO₆] octahedra and [Si₂O(PO₄)₆]^12? heteropolyanions.     

Complex Phosphates in the Li(Na)3]PO4-InPO4 Systems

Subsolidus sections in the systems Li₃PO₄-InPO₄ (950°C) and Na₃PO₄-InPO₄ (800, 900, and 1000°C) have been studied by X-ray powder diffraction. The compound Li₃In(PO₄)₂ has been synthesized, and the nasicon-type solid solution Li_{3(1 ? x)}In_{2 + x}(PO₄)₃ (0.67 ≤ x ≤ 0.80). has been found to exist. In the system Na₃PO₄-InPO₄, the solid solution Na_{3(1 ? x)}In_x/3PO₄ (0 ≤ x ≤ 0.2) and two complex phosphates exist: Na₃In(PO₄)₂ and Na₃In₂(PO₄)₃. These complex phosphates are dimorphic, with the irreversible-transition temperature equal to 675 and 820°C, respectively. Na₃In(PO₄)₂ degrades at 920°C. Ionic conductivity has been measured in some phases in the system.     

Crystal structure and thermal behavior of a chromium-piperazinium phosphate

(C₄N₂H₁₂)CrO(H_1.5PO₄)₂·H₂O has been synthesized hydrothermally using piperazine as organic template. Its crystal structure was solved ab initio using synchrotron powder X-ray diffraction data [monoclinic, a = 16.9649(4) Å, b = 9.8609(2) Å, c = 7.14375(14) Å, and β = 94.896(3)°, space group P2₁/a, Z = 4]. 1D structure is composed by isolated infinite anionic chains [CrO(H_1.5PO₄)₂]_n (vertex-sharing {CrO₆} octahedra joined by phosphate moieties). Their 2D plate-like morphology is propitiated by a very strong inter-chain interaction (P–O···H···O–P symmetric hydrogen bonds). KAS isoconversional method was applied to determine the activation energy for both thermal and thermo-oxidative decomposition of (C₄N₂H₁₂)CrO(H_1.5PO₄)₂·H₂O.     

Contributions on thermal behaviour and crystal chemistry of anhydrous phosphates. XIX. Tri-chromium(II)-bis-phosphate Cr3(PO4)2 (≙ Cr6(PO4)4) – A transition metal(II)-orthophosphate with new structure type

Deep blue-violet single crystals of hitherto unknown chromous orthophosphate have been obtained reducing CrPO₄ by elemental Cr at temperatures above 1050°C in evacuated silica ampoules (NH₄I or I₂ as mineraliser). The complex structure of Cr₃(PO₄)₂ (P2₁2₁2₁, Z = 8, a = 8.4849(10) Å, b = 10.3317(10) Å, c = 14.206(2) Å) contains six crystallographically independent Cr²⁺ per unit cell. Five of them are coordinated by four oxygen atoms which form a distorted (roof shaped) square plane as first coordination sphere at interatomic distances 1.96 Å ? d(Cr? O) ? 2.15 Å. Their coordination is completed by additional oxygen atoms (2 or 3) at distances 2.32 Å ? d(Cr? O) ? 3.21 Å. The sixth Cr²⁺ shows six-fold octahedral coordination with strong radial distortion (d(Cr? O): 1.97, 2.04, 2.15, 2.28, 2.29, 2.53 Å). The four different [PO₄] groups exhibit only minor deviations from ideal tetrahedral geometry (1.51 Å ? d(P? O) ? 1.57 Å, 104.3° ? ∠(O? P? O) ? 114.4°). An unusually low magnetic moment μ_exp = 4.28(2) μ_B (θ_P = ?54.8(5) K) has been observed for Cr²⁺.     

Sur L'Existence d'un Intermediaire Reactionnel Entre Phosphate et Pyrophosphate Acide de Potassium: Cas de K2H8(PO4)2P2O7

On the Existence of Intermediate Reaction Products of Potassium Hydrogen Phosphate and Diphosphate: K₂H₈(PO₄)₂P₂O₇ The crystal structure of K₂H₈(PO₄)₂P₂O₇ has been determined from diffractometer data obtained using MoKα radiation. The space group is Pca2₁ with a = 9.364(2), b = 7.458(2) and c = 19.560(2) Å, V = 1 366.0 ų; d_m = 2.17(1) g/cm³. Z = 4 · μ(MoKα) = 12.47 cm^?1. The structure was solved by direct methods. The crystal structure was refined to R = 0.025 for 416 independent reflexions. Two kinds of PO₄ exist and the mean value of P? O is 1.55(2) Å for one and 1.53(2) Å for the other. In P₂O₇ the angle P? O? P is 135(1)°. The distances P? O of bridge are 1.59(2) and 1.57(2) Å the mean value of P? O in terminals ? PO₃ is 1.51(2) Å. The coordination numbers of the potassium ions are nine and eight. K₂H₈(PO₄)₂P₂O₇, compound with mixed anion PO₄/P₂O₇ may be considered as reactional intermediary between acid orthophosphate and pyrophosphate.     

Synthesis, Crystal Structure and Characterization of a Mixed-Valence Keggin-Structural 12-Molybdophosphoric Acid Compound: NH4(C4N2H12)(C2N2H10)2[Mo 4 V Mo 8 VI PO40]·2H2O

A mixed-valence Keggin-structural 12-molybdophosphoric acid hydrate, NH₄(C₄N₂H₁₂)(C₂N₂H₁₀)₂ [Mo ₄ ^V Mo ₈ ^VI PO₄₀]·2H₂O (1), has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction, elemental analysis, TG, XRD, IR, Raman, UV–Vis diffuse reflection spectrum and XPS spectrum. The compound 1 crystallizes in the monoclinic system with cell parameters of a = 20.668(4) Å, b = 10.827(2) Å, c = 21.508(4) Å, β = 117.070(3)°, V = 4,285.6(14) ų, and space group C _2/c, Z = 4 at 293 K. The final full-matrix least-squares refinement converged to R ₁ = 0.029 for the observed reflections (4,721) with I > 2σ(I) and wR ₂ = 0.065 for all data (4,837) and S = 1.048. Compared with another compound, (C₄N₂H₁₂)(C₂N₂H₁₀)₂[Mo₅P₂O₂₃] (2) (Chen et al., Chin J Struct Chem 30:1178, 2011), compound 1 was obtained via only changing molar ratio of reactants and the pH value of reaction system. Meanwhile, compound 1 contains the same two kinds of organonitrogen ligands, even their molar ratio, but entirely different space architecture and distinct heteropoly blue building block, [Mo ₄ ^V Mo ₈ ^VI PO₄₀]^7?. The crystal packing of 1 presents interesting 1D Zig-zag, 2D laminated and even 3D honeycomb-like configurations.     

Synthesis and crystal structures of two new uranyl coordination compounds obtained in aqueous solutions of 1-butyl-2,3-dimethylimidazolium chloride

Abstract

Two new uranyl coordination compounds, [C₉H₁₇N₂]₃[(UO₂)₂(CrO₄)₂Cl₂(H₂O)₂]Cl·5H₂O (1) and (C₉H₁₇N₂)[(UO₂)(C₂O₄)Cl] (2), have been synthesized by adding potassium dichromate (K₂Cr₂O₇) or oxalic acid dihydrate (H₂C₂O₄·2H₂O) solution into an aqueous solution of uranyl nitrate and 1-butyl-2,3-dimethylimidazolium chloride [Bmmim]Cl. [Bmmim]Cl provides the charge balance and Cl ions that coordinate with uranyl ions. The fundamental building units of 1 and 2 are UO₆Cl pentagonal bipyramidal structures. Compound 1 exhibits a graphene-like structure with a system molar ratio of 1:1 for U:Cr and crystallizes in the orthorhombic space group Pbca, with a = 25.644(3) Å, b = 12.996(14) Å and c = 29.198(4) Å. 16-Membered rings are formed by CrO₄^2? and UO₂²⁺ in the crystal structure of 1. Compound 2 crystallizes in monoclinic space group P2₁/n, with a = 10.759(3) Å, b = 11.395(3) Å, c = 14.149(4) Å, β = 102.962(9)° and shows one-dimensional (1D) serrated chains. Within the crystal structures of 1 and 2, C–H_[Bmmim]Cl?O hydrogen bonds are identified. O–H_water?Cl hydrogen bonds are also detected in the crystal structure for 1.     

Solution and solid state studies with the bis-oxalato building block [Cr(pyim)(C2O4)2]− [pyim = 2-(2′-pyridyl)imidazole]

The preparation, X-ray structure, and variable temperature magnetic study of the new compound {Ba(H₂O)_3/2[Cr(pyim)(C₂O₄)₂]₂}_n·9/2nH₂O (1) [pyim = 2-(2′-pyridyl)imidazole and C₂O₄^2? = dianion of oxalic acid], together with the potentiometric and spectrophotometric studies of the protonation/deprotonation equilibria of the pyim ligand and the ternary complex [Cr(pyim)(C₂O₄)₂]^?, are reported herein. The crystal structure of 1 consists of neutral chains, with diamond-shaped units sharing barium(II), with the two other corners occupied by chromium(III). The two metal centers are connected through bis(bidentate) oxalate. Very weak antiferromagnetic interactions between the chromium(III) ions occur in 1. The values of the protonation constants of the imidazole and pyridyl fragments of pyim as well as the acidity constant of the coordinated pyim in [Cr(pyim)(C₂O₄)₂]^? are determined for the first time by potentiometry and UV–Vis spectroscopy in aqueous solution (25?°C and 0.15 M NaNO₃ as ionic strength).     

Darstellung sowie Kristall- und Molekülstruktur von Triphenylphosphinoxidhydrogenfluorid, (C6H5)3PO · HF

Preparation, Crystal and Molecular Structure of Triphenylphosphineoxide Hydrogen - fluoride (C₆H₅)₃PO · HF (C₆H₅)₃PO · HF was prepared from hydrofluoric acid (40%) and (C₆H₅)₃PO in benzene. It crystallizes in the monoclinic space group P2₁/c with a = 1 032.8(3), b = 1 051.0(7), c = 1695.5(2) pm, β = 121.95(2)° and Z = 4; d (calc./obs.) 1.27/1.26 g ° cm^?3. The structure was determined by direct methods from 2 709 independent reflections and has been refined by full matrix least squares methods to R = 0.049. In the compound HF and (C₆H₅)₃PO are linked by a short H-bond. Some distances: O? F 238.4(5), O? H 142.3, H? F 99.8, P? O 149.5(4) pm. Angle O? H? F 159.8°.     

Etude des spectres vibrationnels et des proprietes physico-chimiques du cyclotriphosphate mixte de nickel et de sodium hexahydrate,NiNa4(P3O9)2.6H2O

A study of the vibrational spectra and physico-chemical properties of nickel and sodium cyclotriphosphate hexahydrate, NiNa₄(P₃O₉)₂.6H₂O. We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate hexahydrate of nickel and sodium, NiNa₄(P₃O₉)₂.6H₂O, between 25 and 700°C by infrared spectrometry, X-ray diffraction, TGA and DTA thermal analyses. This study allows the identification and the crystallographic characterization of a new phase, NiNa₄(PO₃)₆, obtained between 350 and 450°C. NiNa₄(PO₃)₆ crystallizes in the triclinic system, P₋₁, with the following unit cell parameters a = 6.157(3)Å, b = 6.820(6)Å, c = 10.918(6)Å, α = 80.21(5)°, β= 97.80(9)°, γ = 113.49(3)°, V = 409.8 ų, Z = 1, M(19) = 25 and F(19) = 48 (0.0095; 42). The calcination of NiNa₄(PO₃)₆, between 500 and 600°C, leads to a mixture of long-chain polyphosphates NiNa(PO₃)₃ and NaPO₃. The kinetic characteristics of the dehydration of NiNa₄(P₃O₉)₂.6H₂O were determined and discussed. The vibrational spectrum of the title compound, NiNa₄(P₃O₉)₂.6H₂O, was interpreted in the domain of the stretching vibrations of the P₃O₉ rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P₃O₉ ring with D_3h symmetry.     

Synthesis and Solid-State Structure of Cyclobutyltellurium(IV)-Containing Dimeric Tungstoarsenates(III)

The cage-like cyclobutyltellurium(IV)-containing tungstoarsenate(III) dimers [(C₄H₈Te-OH)₂(C₄H₈Te)₆{As₂W₁₇O₆₁(H₂O)}₂]^14? (1) and [{(C₄H₈Te)₂W₂O₅(H₂O)₂As₂W₁₉O₆₇(H₂O)}₂]^16? (2) were synthesized in moderately acidic aqueous medium by reaction of C₄H₈TeI₂ with the lacunary tungstoarsenates(III) [B-α-AsW₉O₃₃]^9? and [As₂W₁₉O₆₇(H₂O)]^14?, respectively. Polyanion 1 was isolated as a mixed cesium-guanidinium salt Cs_8.5(C(NH₂)₃)_5.5[(C₄H₈TeOH)₂(C₄H₈Te)₆{As₂W₁₇O₆₁(H₂O)}₂]·60H₂O (1a), whereas 2 crystallized as a mixed cesium-potassium salt Cs₉K₇[{(C₄H₈Te)₂W₂O₅(H₂O)₂As₂W₁₉O₆₇(H₂O)}₂]·90H₂O (2a). Single crystal X-ray analysis demonstrated that 1a and 2a crystallized in the triclinic space group \( P \bar{1} \), with a = 12.7738(8) Å, b = 18.7490(14) Å, c = 21.9831(14) Å, α = 111.155(4)^o, β = 93.312(3)^o, γ = 99.530(4) and Z = 1 for 1a and a = 19.309(6) Å, b = 24.674(8) Å, c = 26.071(8) Å, α = 63.218(17)°, β = 89.26(16)^°, γ = 79.948(17)^° and Z = 2 for 2a. The polyanion salts 1a and 2a were characterized by solid state NMR (¹H, ¹³C, ¹²⁵Te), FT-IR, TGA-DSC, and elemental analysis.     

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.