Stabilisation of heterobimetallic networks by crown ethers and hydrogen-bonding in [Ni(H2O)6][Cu3Cl8(H2O)2] · (15-crown-5)2 · 2H2O: Structure and magnetism

[Ni(H₂O)₆][Cu₃Cl₈(H₂O)₂] · (15-crown-5)₂ · 2H₂O can be conveniently prepared by the interaction of NiCl₂ · 6H₂O, CuCl₂ · 2H₂O and 15-crown-5 in water. The X-ray crystal structure reveals an ionic complex involved in a hydrogen-bonded two dimensional network with the [Ni(H₂O)₆]²⁺ and [Cu₃Cl₈(H₂O)₂]²⁻ ions sandwiched between the 15-crown-5 macrocycles. The magnetic susceptibility data (4–300 K) and magnetisation isotherms (2–5.5 K; 0–5 T) are best interpreted in terms of intra-trimer ferromagnetic coupling within the [Cu₃Cl₈(H₂O)₂]²⁻ moieties, with J ∼ 6 cm⁻¹, and antiferromagnetic coupling between the trimers, the latter mediated by H-bonding pathways. Comparisons are made to other reported quaternary ammonium salts of [Cu₃Cl₈]²⁻ and [Cu₃Cl₁₂]⁶⁻, most of which display structures that involve close stacking of such Cu(II) trimers, rather than being of the present isolated, albeit H-bonded, types.     

Characterization and structural study of lanthanum citrate trihydrate [La(C6H5O7)(H2O)2]·H2O

[La(C₆H₅O₇)(H₂O)₂]·H₂O was synthesized as precursor material for an aqueous solution-gel route to La-containing multimetal oxides. The compound was characterized by means of FTIR, TGA and pycnometry. The crystallographic structure was solved from powder diffraction data. The symmetry is monoclinic [a=17.097(3) Å, b=9.765(2) Å, c=6.3166(8) Å and β=90.42(1)°, Z_exp=3.96] with space group P2₁/n (14). Direct methods were applied and the model was subsequently least-squares refined (R_B=5.1% and R_wP=12.0%). La³⁺ is nine-fold coordinated, the LaO₉ forming a mono-capped square antiprism. The basic unit is a binuclear entity of two LaO₉ polyhedra having one edge in common. These units are connected along the c-axis through citrate molecules. The carboxylate groups of the citrate are coordinated to La³⁺ in monodentate, bidentate and bridging way. Also the alkoxide group, which carries the proton, is coordinated to La³⁺. Two water molecules complete the coordination sphere, while the third one can be found inbetween the La³⁺-citrate network.     

Conservation of [(C2H4NH3)3N]2·(ZrF7)2·H2O layers during the topotactic dehydration of [(C2H4NH3)3N]2·(ZrF7)2·9H2O

Tren amine cations [(C₂H₄NH₃)₃N]³⁺ and zirconate or tantalate anions adopt a ternary symmetry in two hydrates, [H₃tren]₂·(ZrF₇)₂·9H₂O and [H₃tren]₆·(ZrF₇)₂·(TaOF₆)₄·3H₂O, which crystallise in R32 space group with a_H = 8.871 (2) Å, c_H = 38.16 (1) Å and a_H = 8.758 (2) Å, c_H = 30.112 (9) Å, respectively. Similar [H₃tren]₂·(MX₇)₂·H₂O (M = Zr, Ta; X = F, O) sheets are found in both structures; they are separated by a water layer (O_w(2)-O_w(3)) in [H₃tren]₂·(ZrF₇)₂·9H₂O. Dehydration of [H₃tren]₂·(ZrF₇)₂·9H₂O starts at room temperature and ends at 90 °C to give [H₃tren]₂·(ZrF₇)₂·H₂O. [H₃tren]₂·(ZrF₇)₂·H₂O layers remain probably unchanged during this dehydration and the existence of one intermediate [H₃tren]₂·(ZrF₇)₂·3H₂O hydrate is assumed. O_w(1) molecules are tightly hydrogen bonded with -NH₃⁺ groups and decomposition of [H₃tren]₂·(ZrF₇)₂·H₂O occurs from 210 °C to 500 °C to give successively [H₃tren]₂·(ZrF₆)·(Zr₂F₁₂) (285 °C), an intermediate unknown phase (320 °C) and ZrF₄.     

An open-framework three-dimensional indium oxalate: [In(OH)(C2O4)(H2O)]3·H2O

By hydrothermal reaction of In₂O₃ with H₂C₂O₄·2H₂O in the presence of H₃BO₃ at 155 °C, an open-framework three-dimensional indium oxalate of formula [In(OH)(C₂O₄)(H₂O)]₃·H₂O (1) has been obtained. The compound crystallizes in the trigonal system, space group R3c with , , , Z=6, R₁=0.0352 at 298 K. The small pores in 1 are filled with water molecules. It loses its filled water at about 180 °C without the change of structure, then the bounded water at 260 °C, and completely decompounds at 324 °C. The residue is confirmed to be In₂O₃.     

Synthesis and structure of the silylated benzene radical anion salts [K([18]crown-6){C6H4(SiMe3)2-1,4}] and [K([18]crown-6)(THF)2][C6H2(SiMe3)4-1,2,4,5]

The crystalline compound [K([18]crown-6){C₆H₄(SiMe₃)₂-1,4}] (1) was prepared by the low-temperature reduction of the para-disilylated benzene with K/[18]crown-6 in toluene followed by recrystallisation from the same solvent. Reduction of 1,2,4,5-tetrasilylated benzene with 2(K/[18]crown-6) in toluene produced a hydrocarbon-insoluble powder identified as the dianionic derivative [K([18]crown-6)]₂[C₆H₂(SiMe₃)₄-1,2,4,5)] (2), which upon crystallisation from THF/Et₂O yielded [K([18]crown-6)(THF)₂][C₆H₂(SiMe₃)₄-1,2,4,5] (3). An X-ray diffraction study revealed that 1 comprised a contact ion pair with the crown-encapsulated K cation η⁵-connected to the planar ring of the substituted benzene radical anion, while 3 contained a well separated cation and anion.     

Crystal and molecular structures of the Rh[(C2H5O)2PS2]3 and Co[(C6H5O)2PS2]3 chelate compounds

The crystal structures of the Rh[(EtO)₂PS₂]₃ (I) and Co[(PhO)₂PS₂]₃ (II) chelate compounds were determined from X-ray diffraction (XRD) data (CAD-4 diffractometer, MoK _β radiation, 1193 F _hkl , R = 0.0516 for I and 513 F _hkl , R = 0.0305 for II). Crystals I are monoclinic: a = 14.233(3) Å, b = 13.570(3) Å, c = 14.272(3) Å; β = 90.66(3)°, V = 2756.3(10) ų, Z = 4, ρ_calc = 1.587 g/cm³, space group C2/c. Crystals II are trigonal: a = 15.149(2) Å, c = 30.306(6) Å; V = 6023.2(16) ų, Z = 6, ρ_calc = 1.493 g/cm³, space group R3ˉ. Structures I and II consist of discrete mononuclear molecules. The coordination polyhedra of the M atoms (M = Rh, Co) are distorted octahedra formed by six sulfur atoms of three cyclic bidentate (RO)₂ PS₂⁻ ligands. Original Russian Text Copyright ? 2008 by R. F. Klevtsova, L. A. Glinskaya, and S. V. Larionov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 2, pp. 330–334, March–April, 2008.     

Ho(NO3)3(C2H5O2N)4·H2O的低温热容和热力学函数

合成了稀土(钬, Ho)-氨基酸(甘氨酸, C₂H₅O₂N)二元配合物Ho(NO₃)₃(C₂H₅O₂N)₄·H₂O, 并且通过化学分析、元素分析和红外(IR)光谱对配合物进行了表征. 用高精度全自动绝热量热仪, 测定了该配合物在80-390 K温度区间的定压摩尔热容(C_p,m). 利用实验测定的热容数据, 采用最小二乘法, 将热容曲线上热容峰以外的两段平滑区的摩尔热容对折合温度进行拟合, 建立了热容随折合温度变化的多项式方程. 根据热容与焓、熵的热力学关系,计算出了配合物在80-390 K温度区间内,每隔5 K,相对于298.15 K的摩尔热力学函数(H_T,m-H_298.15,m)和(S_T,m-S_298.15,m). 通过热容曲线分析, 计算出了350 K附近转变过程的焓变(Δ_trsH_m)和熵变(Δ_trsS_m). 用差示扫描量热法(DSC)测定了配合物的热稳定性.     

Synthesis and structure of three manganese oxalates: MnC2O4·2H2O, [C4H8(NH2)2][Mn2(C2O4)3] and Mn2(C2O4)(OH)2

Three manganese oxalates have been hydrothermally synthesized, and their structures determined by single-crystal X-ray diffraction. MnC₂O₄·2H₂O (I) is orthorhombic, P2₁2₁2₁, , , , , Z=4, final R, R_w=0.0832, 0.1017 for 561 observed data (I>3σ(I)). The one-dimensional structure consists of chains of oxalate-bridged manganese centers. [C₄H₈(NH₂)₂][Mn₂(C₂O₄)₃] (II) is triclinic, , , , , α=81.489(2)°, β=81.045(2)°, γ=86.076(2)°, , Z=1, final R, R_w=0.0467, 0.0596 for 1773 observed data (I > 3σ (I)). The three-dimensional framework is constructed from seven coordinate manganese and oxalate anions. The material contains extra-framework diprotonated piperazine cations. Mn₂(C₂O₄)(OH)₂ (III) is monoclinic, P2₁/c, , , , β=91.10(3)°, , Z=1, final R₁, wR2=0.0710, 0.1378 for 268 observed data (I>2σ (I)). The structure is also three dimensional, with layers of MnO₆ octahedra pillared by oxalate anions. The hydroxide group is found bonded to three manganese centers resulting in a four coordinate oxygen.     

Crystal structure of [Cs2Na(H2O)2(C23H16O3)(C23H15O3)3]

The crystal structure of a double salt of sodium and cesium with 2-diphenylacetyl-1,3-indandione of the composition [Cs₂Na(H₂O)₂(C₂₃H₁₆O₃)(C₂₃H₁₅O₃)₃] (I) was studied by X-ray crystallography. The crystals of I are monoclinic, Z = 2, space group P2₁/n, a = 10.212(2) ?, b = 23.479(5) ?, c = 15.638(3) ?, β = 98.30(03)°. The compound contains [Cs₂NaO₁₀] trimers, in which the central Na atom shares two edges with two Cs atoms through deprotonated bridging ligands. The trimers are connected to adjacent trimers by paired C-H...O contacts to form layers. The layers form an infinite open framework via hydrogen bonds between the oxygen atoms of keto groups of noncoordinated indandione moieties and water molecules that enter the cesium coordination sphere in trimers of the adjacent layers.     

Syntheses and structures of three new scandium selenites: Sc2(SeO3)3·H2O, Sc2 (SeO3)3·3H2O and CsSc3(SeO3)4 (HSeO3)2·2H2O

Three new hydrated scandium selenites have been hydrothermally synthesized as single crystals and structurally and physically characterized. Sc₂(SeO₃)₃·H₂O crystallizes as a new structure type containing novel ScO₇ pentagonal bipyramidal and ScO₆₊₁ capped octahedral coordination polyhedra. Sc₂(SeO₃)₃·3H₂O contains typical ScO₆ octahedra and is isostructural with its M₂(SeO₃)₃·3H₂O (M=Al, Cr, Fe, Ga) congeners. CsSc₃(SeO₃)₄(HSeO₃)₂·2H₂O contains near-regular ScO₆ octahedra and has essentially the same structure as its indium-containing analogue. All three phases contain the expected pyramidal [SeO₃]^2- selenite groups. Crystal data: Sc₂(SeO₃)₃·3H₂O, M_r=524.85, trigonal, R3c (No. 161), , , , Z=6, R(F)=0.018, wR(F²)=0.036; Sc₂(SeO₃)₃·H₂O, M_r=488.82, orthorhombic, P2₁2₁2₁ (No. 19), , , , , Z=4, R(F)=0.051, wR(F²)=0.086; CsSc₃(SeO₃)₄(HSeO₃)₂·2H₂O, M_r=1067.60, orthorhombic, Pnma (No. 62), , , , , Z=4, R(F)=0.035, wR(F²)=0.070.     

Na4H3[SiW9Al3(H2O)3O37]·12H2O/H2O: a new system for selective oxidation of alcohols with H2O2 as oxidant

This work describes a catalytic system consisting of both Na₄H₃[SiW₉Al₃(H₂O)₃O₃₇]·12H₂O(SiW₉Al₃) and water as solvents (a small quantity of organic solvents were used as co-solvent for a few substrates) that can be good for selective oxidation of alcohols to ketones (aldehydes) using 30% H₂O₂ without any phase-transfer catalyst under mild reaction conditions. The catalyst system allows easy product/catalyst separation. Under the given conditions, the secondary hydroxyl group was highly chemoselectively oxidized to the corresponding ketones in good yields in the presence of primary hydroxyl group within the same molecule, and hydroxides are selectively oxidized even in the presence of alkene. Benzylic alcohols were selectively oxidized to the corresponding benzaldehydes in good yields without over oxidation products in solvent-free conditions. Nitrogen, oxygen, sulfur-based moieties, at least for the cases where these atoms are not susceptible to oxidation, do not interfere with the catalytic alcohol oxidation.     

Solvothermal synthesis, crystal structure, magnetic and luminescent properties of (H3O)6·[Co4(H2O)4(HPMIDA)2(PMIDA)2)]·2H2O

A cobalt phosphonate (H₃O)₆·[Co₄(H₂O)₄(HPMIDA)₂(PMIDA)₂)]·2H₂O, 1, has been synthesized from a mild solvothermal reaction of Co(II) ion with N-(phosphonomethyl)iminodiacetic acid (H₄PMIDA). Compound 1 crystallizes in the triclinic space group with cell parameters of , , , α=93.06(3)°, β=99.66(3)°, γ=90.34(3)° and Z=1. Compound 1 shows a novel tetra-nuclear molecular structure. In the crystal lattice, molecules of 1 hydrogen bond to each other to form two-dimensional (2D) layers, which are further linked together by the co-crystallized H₂O molecules and H₃O⁺ counter ions through hydrogen bonding to form the 3D supramolecular network. Thermogravimetric analysis, IR spectrum, magnetic susceptibility and luminescent spectra are given.     

Low-temperature heat capacity of triangle antiferromagnetic molecular clusters K12[(VO)3(SbW9O33)2]·15H2O and K12[(VO)3(BiW9O33)2]·29H2O

Energy level diagrams have been determined for two molecular clusters, K₁₂[(VO)₃(SbW₉O₃₃)₂]·15H₂O and K₁₂[(VO)₃(BiW₉O₃₃)₂]·29H₂O, by low-temperature heat capacity measurements down to 85 mK under magnetic field strengths up to 9 T. Both compounds exhibit a broad heat capacity peak dependent upon the magnetic field, which can be explained by the thermal excitation in the magnetic energy levels. A detailed analysis based on the numerical calculation reveals that the spin-spin interaction between the V⁴⁺ ions includes a Dzyaloshinskii-Moriya interaction.     

Synthesis and Structure of a New Organic-Inorganic Framework with Tetranuclear Clusters, [Co4(OH)2(H2O)2](C4H11N2)2[C6H2(COO)4]2·3H2O

A new hybrid organic-inorganic three-dimensional compound, [Co₄(OH)₂(H₂O)₂](C₄H₁₁N₂)₂[C₆H₂(CO₂)₄]₂·3H₂O 1, has been synthesized via hydrothermal reactions and characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and magnetic techniques. Compound 1 crystallizes in the monoclinic space group P2₁/n (no. 14) with a=6.3029(9) Å, b=16.413(2) Å, c=17.139(2) Å, β=98.630(2)°, V=1735.0(4) ų, Z=2. Compound 1 contains tetranuclear Co₄(μ₃-OH)₂(H₂O)₂ clusters that are inter-linked by pyromellitate bridging ligands into a three-dimensional structure containing one-dimensional tunnels along the a-axis with water and pendant monoprotonated piperazine molecules in the center. The variable temperature magnetic susceptibility was measured from 2 to 300 K at 5000 Oe showing a predominantly anti-ferromagnetic interaction in 1, and the field dependence of magnetization was measured at 2, 5, 15, and 20 K indicating the competition of magnetic interactions in the tetranuclear centers.     

Supramolecular pseudo-rotaxane type complexes from π-extended TTF dimer crown ether and C60

A new cyclophane-type crown ether endowed with two exTTF units forms supramolecular ensembles with different dibenzylammonium salts with a binding constant of K_a∼50 M⁻¹ determined by ¹H NMR and fluorescence experiments. Cyclic voltammetry studies show the existence of electronic interaction between the exTTF units due to the flexible nature of the crown ether chains.     

Preparation and configurational isomerism of ditertiary stibine sulfides, (C6H5)(CH3)(S)SbCH2Sb(CH3)(C6H5) and [(C6H5)(CH3)(S)Sb]2(CH2)3

Asymmetric ditertiary stibine sulfides (C₆H₅)(CH₃)(S)SbCH₂Sb(CH₃)(C₆H₅) and [(C₆H₅)(CH₃)(S)Sb]₂(CH₂)₃ have been prepared. It was found that they exist as only one of two possible diastereomers in the crystalline state. However, isomerization to the other form takes place in solution, resulting in an equilibrium mixture. A possibility of configurational lability of tertiary stibine sulfide was suggested for the first time.     

New binuclear vanadium(III) and (IV) squarate species: synthesis, structure and characterization of [V(OH)(H2O)2(C4O4)]2·2H2O and (NH4)[(VO)2(OH)(C4O4)2(H2O)3]·3H2O

Two new vanadium squarates have been synthesized, characterized by infrared and thermal behavior and their structures determined by single crystal X-ray diffraction. Both structures are made of discrete, binuclear vanadium entity but in 1, [V(OH)(H₂O)₂(C₄O₄)]₂·2H₂O the vanadium atom is trivalent and the entity is neutral while in 2, (NH₄)[(VO)₂(OH)(C₄O₄)₂(H₂O)₃]·3H₂O, the vanadium atom is tetravalent and the entity is negatively charged, balanced by the presence of one ammonium ion. Both molecular anions are bridged by two terminal μ₂ squarate ligands. 1 crystallizes in the triclinic system, space group P-1, with lattice constants a=7.5112(10) Å, b=7.5603(8) Å, c=8.2185(8) Å, α=106.904(8)°, β=94.510(10)°, γ=113.984(9)° while 2 crystallizes in the monoclinic system, space group C2/c, with a=14.9340(15) Å, b=6.4900(9) Å, c=17.9590(19) Å and β=97.927(12)°. From the magnetic point of view, V(III) binuclear species show ferromagnetic interactions at low temperatures. However, no anomalies pointing to magnetic ordering are observed down to 2 K.     

Hydrothermal synthesis and characterization of layered vanadium phosphite: [HN(C2H4)3N][(VO)2(HPO3)2(OH)(H2O)]·H2O

A novel compound, [HN(C₂H₄)₃N][(VO)₂(HPO₃)₂(OH)(H₂O)]·H₂O, was hydrothermally synthesized and characterized by single crystal X-ray diffraction. This compound crystallizes in the monoclinic system with the space group C2/c and cell parameters a=11.0753(3) Å, b=17.8265(6) Å, c=16.5229(5) Å, and β=92.362(2)°. The structure of the compound consists of vanadium phosphite layers which are built up from the infinite one-dimensional chains of [(VO)(H₂O)(HPO₃)₂]²⁻ of octahedral VO₅(H₂O) and pseudo pyramidal [HPO₃], and bridging binuclear fragments of [VO(OH)]₂. Thermogravimetric analysis and magnetic susceptibility data for this compound are given.     

Single-crystal characterization of Co7(OH)6(H2O)3(C4H4O4)47H2O; A new cobalt succinate identified through high-throughput synthesis

A new form of cobalt succinate has been discovered using high-throughput methods and its structure was solved by single crystal X-ray diffraction. Co₇(C₄H₄O₄)₄(OH)₆(H₂O)₃7H₂O crystallizes in the monoclinic space group P2₁/c with cell parameters: a=7.888(2) Å, b=19.082(6) Å, c=23.630(7) Å, β=91.700(5)°, V=3555(2) Å³, R₁=0.0469. This complex structure, containing 55 crystallographically distinct non-hydrogen atoms, is compared to the previously reported nickel phase, characterized using ab initio structure solution from synchrotron powder diffraction data.     

[(n-C16H33)N(CH3)3]2[TiF6]·2H2O的合成、结构和热稳定性

利用水热法在150 ℃合成了新的化合物六氟钛酸十六烷基三甲基胺二水合物([(n-C16H33)N(CH3)32[TiF6]·2H2O), 并利用单晶X射线衍射技术解析了其结构, 同时利用傅立叶变换红外光谱、元素分析及热分析技术加以佐证. 该化合物由六氟钛酸根离子(TiF2-6)、水分子及十六烷基三甲基胺离子([(n-C16H33)N(CH3)3]+)组成, 属于单斜晶系, 其空间群为C2/c. 氢键在其构筑三维结构时起着重要的作用.