Hydrothermal synthesis and characterization of two new arsenic–vanadate compounds with the same cluster anion [As8V14O42(H2O)]4−

Two new arsenic–vanadate compounds [Co(C₄H₁₃N₃)₂]₂[As₈V₁₄O₄₂(H₂O)]?·?3.5H₂O (1) and (C₂N₂H₉)₂(C₂N₂H₁₀)[As₈V₁₄O₄₂(H₂O)]?·?2.33H₂O (2) have been hydrothermally synthesized and characterized by X-ray single crystal diffraction, IR spectra and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic space group P ₂(1)/c, a?=?24.649(9)?Å, b?=?13.364(5)?Å, c?=?22.463(8)?Å, β?=?104.008(5)°, V?=?7180(5)?ų, Z?=?4, R ₁?=?0.0787, and wR ₂?=?0.1859. Compound 2 crystallizes in rhombohedral system with space group R3c, a?=?b?=?c?=?22.2405(5)?Å, α?=?β?=?γ?=?110.4030(10)°, V?=?8163.4(3)?ų, Z?=?6, R ₁?=?0.0341 and wR ₂?=?0.0941. The structural analyses show that both compounds have the same discrete cluster anion [As₈V₁₄O₄₂(H₂O)]^4?. Moreover, in 1, the polyanions are connected through van der Waals forces to generate soft channels that are filled by [Co(C₄H₁₃N₃)₂]²⁺ cations and water. In 2, water and organic molecules link cluster anions to create the supramolecular assembly through hydrogen bonding.     

Synthesis and Crystal Structure of Two Decavanadates Cluster Metal Complexes: [Co(H2O)6]2[H2V10O28]·6H2O and (NH4)2[Ca(H2O)7]2[V10O28]

Two new decavanadate metal complexes, [Co(H₂O)₆]₂[H₂V₁₀O₂₈]·6H₂O (1) and (NH₄)₂[Ca(H₂O)₇]₂[V₁₀O₂₈] (2), have been synthesized under hydrothermal condition by using chlorhydric acid as the initiator at 120 °C. The aqueous NaVO₃ solution with an aqueous solution of CoCl₂·6H₂O were used for generating 1 and aqueous CaCl₂·2H₂O and NH₄VO₃ solution were employed for creating 2. Compound 1 consisted of discrete hexa-aqua-cobalt [Co(H₂O)₆]²⁺ cations, [H₂V₁₀O₂₈]⁴⁻ anions and non-coordination water molecules. Compound 2 were composed of hepta-aqua-calcium [Ca(H₂O)₇]²⁺ cations, ammonium NH₄ ⁺ and [V₁₀O₂₈]⁶⁻ anion. For compound 2, the distorted pentagonal bipyramid [Ca(H₂O)₇]²⁺ is uncommon. In the crystal lattice, hydrogen bonds played an important role on connecting cations, anions and non-coordinated water molecules to form the three-dimensional network.     

New supramolecular adducts of chloroaquacomplexes [M3(μ3-S)S3?xSexCly(H2O)9?y](4?y)+ (M = Mo, W) with cucurbit[6]uril

New supramolecular adducts of cucurbit[6]uril with triangular cluster chloroaquacomplexes of Mo and W with mixed sulfido-selenido bridging ligands, {[W₃S₃Se(H₂O)₇Cl₂]₂(C₃₆H₃₆N₂₄O₁₂)}Cl₂·15H₂O (1), {[W₃S_1.5Se_2.5Cl_1.5(H₂O)_7.5]₂(C₃₆H₃₆N₂₄O₁₂)}Cl₅·18.5H₂O (2), and {[Mo₃SSe₃(H₂O)_7.5Cl_1.5]₂× (C₃₆H₃₆N₂₄O₁₂)}C_l5·11H₂O (3) are obtained treating the mixture of products in Mo-S-Se-Br and W-S-Se-Br systems, isolated, and structurally characterized. In all compounds, the supramolecular structure is based on hydrogen bonded associates of cucurbit[6]uril molecule with two cluster cations.     

Hydrothermal syntheses and crystal structures of two transition metal complexes supported by vanadate {V4O12}: {[ M (dpa)2]2V4O12} ( M = Co,Ni. dpa = 2,2′-dipyridylamine)

Hydrothermal reactions have been exploited in the syntheses of two new metavanadates, {[Co(dpa)₂]₂V₄O₁₂}?·?H₂O (1) and {[Ni(dpa)₂]₂V₄O₁₂}?·?H₂O (2), which were characterized by X-ray diffraction, IR and thermogravimetric analysis. Crystal data: C₄₀H₃₈N₁₂O₁₃Co₂V₄ (1) monoclinic. P2(1), a?=?10.126(2), b?=?17.639(4), c?=?12.930(3) Å,?α?= 90°,?β?= 98.356(4)°,?γ?= 90°, Z?=?2; C₄₀H₃₈N₁₂O₁₃Ni₂V₄ (2) monoclinic. P2(1), a?=?10.1037(9), b?=?17.6680(14), c?=?12.8832(10) Å,?α?= 90°,?β?= 98.423(2)°,?γ?= 90°, Z?=?2. The two complexes are isomorphic and their structures consist of a [V₄O₁₂]^4? cluster bound to two [M(dpa)₂]²⁺ moieties through the terminal oxygen atoms in a trans-conformation; the [V₄O₁₂]^4? cluster adopts a chair-like configuration.     

A new organic–inorganic hybrid based on Mn–salen and decavanadate

An organic–inorganic hybrid based on Mn-salen and decavanadate, [NH₄]₂[Mn(salen)(H₂O)₂]₄[V₁₀O₂₈]?·?6H₂O (1) (salen?=?N,N′-ethylene-bis(salicylideneiminate)), has been synthesized by the strategy of secondary building units in mixed methanol–water solution and was structurally characterized by single-crystal X-ray diffraction, elemental analyses, IR, and UV-Vis. The [Mn(salen)(H₂O)₂]⁺ cations and water molecules are located in the interspaces among the polyoxoanions [V₁₀O₂₈]^6? forming a POM-based supramolecule. Compound 1 is the first example of metal-Schiff-base polyoxovanadates. The photocatalytic analysis, cyclic voltammetry, and electrocatalytic analysis of 1 have been investigated.     

Polyoxidovanadate complexes: synthesis,structures and catalytic oxidative bromination of phenol red

By selecting appropriate ligands, two polyoxidovanadate complexes, [Ni(en)₂]₃[V₁₈O₄₂Cl]·7H₂O·2H₃O⁺ (1) and [H₂N(CH₃)₂]₃[PV₁₄O₄₂]·2TMP·6H₃O⁺ (2), have been synthesized at different pH values using V₂(SO₄)₃, Ni(CH₃COO)₂, and H₆TTHA (for 1), VO(acac)₂ and TPP (for 2) (en = C₂H₈N₂, TPP = thiamine pyrophosphate, TMP = thiamine monophosphate, H₆TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid). The complexes have been characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TG), and single crystal X-ray diffraction. The complexes catalyze the oxidation of the organic substrate phenol red in the presence of H₂O₂ and bromide, and the reaction system is considered as a model for hydrogen peroxide determination. The reaction rate constants (k) for 1 and 2 are calculated as 3.729 × 10³ and 4.083 × 10³ (mol L)^?2 s^?1. The maximum conversion rate of phenol red for 1 is 83.32%, while for 2 is 81.12%.     

Asymmetric dinuclear hydroxyl and ethoxyl citrato dioxovanadates(V)

Asymmetric citrato dioxovanadates(V), [Hneo]₄[V₂O₄(R-Hcit)(OH)][V₂O₄(S-Hcit)(OH)]?·?4H₂O (1) and [Ni(phen)₃]₂[V₂O₄(R-Hcit)(OC₂H₅)][V₂O₄(S-Hcit)(OC₂H₅)]?·?4H₂O (2) and (H₄cit?=?citric acid, neo?=?2,9-dimethyl-1,10-phenanthroline, phen?=?1,10-phenanthroline) are isolated with the help of large counterions. Structural analyses of complexes 1 and 2 show that vanadium atoms are coordinated by tridentate citrate ligand and hydroxy or ethoxy groups, respectively. The insertions of hydroxy and ethoxy groups give new examples of the mixed RO-bridges for vanadium–citrate complexes.     

pH-Dependent Assembly of Two Novel Organic–inorganic Hybrids Based on Vanadoantimonate Clusters

Two novel organic–inorganic hybrid vanadoantimonate compounds, [Zn₂(dien)₃][{Zn(dien)}₂V₁₆Sb₄O₄₂(H₂O)]·4H₂O (1) and [Zn(dien)₂]₂ [{Zn(dien)}₂(V₁₄Sb₈O₄₂)₂(H₂O)]·4H₂O (2) (dien = Diethylenetriamine), have been synthesized hydrothermally at different pH value, and structurally characterized by elemental analyses, FT-IR, XPS, TGA and single crystal X-ray diffraction analysis. Compound 1 is composed of the rare [V₁₆Sb₄O₄₂]⁸⁻ cluster covalently linked by two [Zn(dien)]²⁺ coordination cations to yield a novel one-dimensional linear chain. Compound 2 exhibits a one-dimensional zigzag chain constructed from the [V₁₄Sb₈O₄₂]⁴⁻ cluster and [Zn(dien)]²⁺ coordination polymer. The two examples represent the first one-dimensional assemblies based on vanadoantimonate cluster and the metal–organic complex moieties.     

Polyoxometalate tri-supported transition metal complexes containing mixed-valent transition metal ions

Three compounds, [AsMo₈V₆O₄₂][Cu(2,2?-bpy)₂]₂[Cu(2,2?-bpy)]·4H₂O (1), [PMo₈V₆O₄₂][Cu(2,2?-bpy)₂]₂[Cu(2,2?-bpy)]·3H₂O (2) and [PMo₈V₆O₄₂][Cu(2,2?-bpy)₂]₂[Cu(2,2?-bpy)]·3.5H₂O (3), have been synthesized under hydrothermal conditions and characterized by IR, UV–vis, XRD, TG, elemental analysis, and X-ray diffraction analysis. Single-crystal X-ray structure analysis reveals that 1 and 2 are isostructural and isomorphous, whereas 2 and 3 are polymorphs. Polymorphs of 1 have not been synthesized yet. The mixed-valent transition metal ion in 1–3 has been further confirmed by TG analyses. Catalytic properties of 1 and 2 have also been studied.     

Functionalized Sandwich-Type Polyoxometalates Based on the Polynuclear Manganese Cluster and Imidazole Ligands

Two polynuclear manganese(II) sandwiched heteropolytungstates, Na₁₀(HC₃H₄N₂){[Na(H₂O)][Mn(C₃H₄N₂)]₃[SbW₉O₃₃]₂}·20H₂O (1) and (C₄H₇N₂)₁₀[Mn₄(H₂O)₂(PW₉O₃₄)₂] (2), have been obtained by conventional aqueous synthesis method and characterized by IR spectra, TG, elemental analyses and single crystal X-ray diffraction. In compound 1, the three-nuclear manganese cluster is sandwiched by two [B-α-SbW₉O₃₃]⁹⁻ units, and each manganese (II) is coordinated by one imidazole (im) molecule. Differently, compound 2 has a four-nuclear manganese (II) cluster with two coordination water molecules. The 2-methylimidazole (mim) molecules float around the polyanions and connect them into a 3D supramolecular framework by hydrogen bondings. The magnetic investigation for compound 1 indicates the existence of weak antiferromagnetic interaction in the sandwiched three-nuclear [Mn(C₃H₄N₂)]₃ cluster.     

Syntheses,Structures and Properties of Three Heteonuclear Complexes Containing [V<Subscript>10</Subscript>O<Subscript>28</Subscript>]<Superscript>6−</Superscript> Units

Three heteonuclear complexes containing [V₁₀O₂₈]⁶⁻ units, {[Cu(pyr)(H₂O)₄]₂(H₃O)₂[V₁₀O₂₈] · 13.5H₂O}_n (1), {[Ni(pyr)(H₂O)₄]₂(H₃O)₂[V₁₀O₂₈] · 9.5H₂O}_n (2) and [Zn₂(H₂O)₁₄(V₁₀O₂₈)] · H₂PPZ (3) are synthesized and characterized by elemental analyses, IR, single crystal X-ray analyses. The complex 1 and 2 have the similar structures which are composed of the [V₁₀O₂₈]⁶⁻ cluster anion and 1D chain {[M (pyr)(H₂O)₄]²⁺}_n (M = Cu Ni) cations bridged by pyrazine. In the complex 3, Zn²⁺ with two coordination modes is bridged by water molecules to build 1D zigzag chains, and then is linked to the bridging oxygen atoms from [V₁₀O₂₈]⁶⁻ to generate a 2D grid architecture filled with the protoned piperazine (PPZ) molecules. In this paper, the magnetic properties of complex 2 are characterized.     

Supramolecular inclusion of a pillared double-layered host by an anion-directed second-sphere coordination

In this paper, we have illustrated the utilisation of a second-sphere coordination approach to construct supramolecular inclusion solids with varieties of guest molecules. A flexible molecule N,N,N′,N′-tetra-p-methylbenzyl-ethylenediamine (L1) bearing doubly protonated H-bond donors was designed, capable of forming N–H…Cl hydrogen bonds with a crystallographically unique chloride anion, to construct an anion-directed ligand. The pillared double-layered host framework was constructed by an anion-directed ligand and primary coordination sphere [CoCl₄]^2 ?  through weak C–H…Cl hydrogen-bonding interactions. A variety of guest molecules, such as p-anisaldehyde, 1,4-dimethoxy-2,5-bis(methoxymethyl)benzene, can be included, leading to the formation of novel supramolecular inclusion solids: [L1]·4[H]⁺·[CoCl₄]^2 ? ·2Cl^? ·1.5[C₈H₈O₂]·0.25[CH₃OH] (1) and [L1]·4[H]⁺·[CoCl₄]^2 ? ·2Cl^? ·1.5[C₁₂H₂₀O₄]·0.5[CH₃OH] (2).

We have presented herein the utilisation of a second-sphere coordination approach to construct supramolecular inclusion solids with a variety of guest molecules. A novel type of a pillared double-layered host framework was constructed by a second-sphere coordination between the anion-directed ligand (L1 = N,N,N′,N′-tetra-p-methylbenzyl-ethylenediamine) and [CoCl₄]^2 ?  through weak C–H…Cl hydrogen-bonding interaction, and a variety of guest molecules, such as p-anisaldehyde, 1,4-dimethoxy-2,5-bis(methoxymethyl)benzene, can be included, leading to the formation of supramolecular inclusion solids: [L1]·4[H]⁺·[CoCl₄]^2 ? ·2Cl^? ·1.5[C₈H₈O₂]·0.25[CH₃OH] (1) and [L1]·4[H]⁺·[CoCl₄]^2 ? ·2Cl^? ·1.5[C₁₂H₂₀O₄]·0.5[CH₃OH] (2)

     

Supramolecular Systems Based on Ca2+, [Mo3O2S2Cl6(H2O)3]2s-, [Mo3S4Cl6.75Br0.25(H2O)2]3s- and Cucurbit[6]uril

Adducts of cucurbit[6]uril with Ca²⁺ and trinuclear cluster chloroaquacomplexes (H₉O₄)₂(H₇O₃)₂[(Ca(H₂O)₅)2(C₃₆H₃₆N₂₄O₁₂)]Cl₈·0.67H₂O (1) and [(Ca(H₂O)₅)₂(C₃₆H₃₆N₂₄O₁₂)]× [Mo₃O₂S₂Cl₆(H₂O)₃]₂·13H₂O (2) are obtained and structurally characterized. The structures of both compounds contain polymeric [Ca(H₂O) _n ]₂² CB[6]∞ cations that form infinite columns; the space between them is filled with Cl^s- (1) and [Mo₃O₂S₂Cl₆(H₂O)₃]^2s- (2). A new (H₇O₃)₂(H₅O₂)× [Mo₃S₄Cl_6.25Br_0.25(H₂O)₂](C₃₆H₃₆N₂₄O₁₂)·CH₂Cl₂·6H₂O complex (3) is also obtained and structurally characterized.     

Coordination interactions in the crystalline lattice of alkaline ions with the polyoxometalate [V12B18O60H6]10− ligand

In the present work, the synthesis and structural characterization of two new polyoxovanadoborate (BVO) frameworks, based on the [V₁₂B₁₈O₆₀H₆]^10? polyanion, are reported, K(H₃O)(enH₂)₄[V₁₂B₁₈O₆₀H₆]·9.60H₂O (1) and Li₈(NH₄)₂[V₁₂B₁₈O₆₀H₆]·8.02H₂O (2). Both compounds are obtained in a mixed valence ratio of 10V^IV/2V^V. Framework 1 is characterized by potassium ions coordinated by the BVO cluster and ethylenediammonium and hydronium ions as charge-compensating agents. In framework 2, the BVO clusters are coordinating lithium ions and the charge is compensated by ammonium ions. Using the SHAPE 2.1 program, it was possible to calculate the best geometry for the existing lithium and potassium ions. For 2, the lithium ions are five-coordinate, best described by a square pyramid (SPY-5), while the coordination sphere around the potassium ions in 1 are six-coordinate. For 1, the coordination sphere of the existing potassium ions in the framework can be described as trigonal prism (TPR-6). Calculations were also done for a previously reported cluster [Na₁₀[(H₂O)V₁₂B₁₈O₆₀H₆]·18H₂O] (3), in which the sodium ions are six-coordinate but in two different geometries, these being octahedral and TPR-6. The influence of the interactions of the alkali ions with the [V₁₂B₁₈O₆₀H₆]^10? polyanion, on the vanadate and borate absorption bands observed in the infrared spectra, is discussed.     

[TMPA]4[Si8O20] · 34 H2O and [DDBO]4[Si8O20] · 32 H2O are heteronetwork clathrates with 1,1,4,4-tetramethylpiperazinium (TMPA) and 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane (DDBO) guest cations

[TMPA]₄[Si₈O₂₀] · 34 H₂O ( 1 ) and [DDBO]₄[Si₈O₂₀] · 32 H₂O ( 2 ) have been prepared by crystallization from aqueous solutions of the respective quaternary alkylammonium hydroxide and SiO₂. The crystal structures have been determined by single-crystal X-ray diffraction. 1 : Monoclinic, a = 16.056(2), b = 22.086(6), c = 22.701(2) Å, β = 90.57(1)° (T = 210 K), space group C2/c, Z = 4. 2 : Monoclinic, a = 14.828(9), b = 20.201(7), c = 15.519(5) Å, β = 124.13(4)° (T = 255 K), space group P2₁/c, Z = 2. The polyhydrates are structurally related host-guest compounds with three-dimensional host frameworks composed of oligomeric [Si₈O₂₀]^8? anions and H₂O molecules which are linked via hydrogen bonds. The silicate anions possess a cube-shaped double four-ring structure and a characteristic local environment formed by 24 H₂O molecules and six cations (TMPA, [C₈H₂₀N₂]²⁺, or DDBO, [C₈H₁₈N₂]²⁺). The cations themselves reside as guest species in large, irregular, cage-like voids. Studies employing ²⁹Si NMR spectroscopy and the trimethylsilylation method have revealed that the saturated aqueous solutions of 1 and 2 contain high proportions of double four-ring silicate anions. Such anions are also abundant species in the saturated solution of the heteronetwork clathrate [DMPI]₆[Si₈O₁₈(OH)₂] · 48.5 H₂O ( 3 ) with 1,1-dimethylpiperidinium (DMPI, [C₇H₁₆N]⁺) guest cations.     

Two bis­(ammonium) 1,5‐naphthalene­disulfonate salts

The title compounds, bis­(ammonium) naphthalene‐1,5‐di­sul­fon­ate, 2NH₄⁺·C₁₀H₆O₆S₂²⁻, and bis­[1‐(hydroxy­methyl)‐3,5,7‐tri­aza‐1‐azoniatri­cyclo­[3.3.1.1^3,7]­decane] 1,5‐naphthalene­di­sul­fon­ate, 2C₇H₁₅N₄O⁺·C₁₀H₆O₆S₂²⁻, were prepared from the acid‐promoted reaction of hexa­methyl­enetetr­amine. In both structures, the di­sulfonate anion is positioned on an inversion center, with each sulfonate group contributing to the supramolecular assemblies via hydrogen bonds. The ammonium cations are linked to sulfonate groups by four distinct N⁺—H⃛⁻O—S contacts [N⃛O = 2.846 (2)–2.898 (2) Å and N—H⃛O = 160 (2)–175 (2)°], whereas the 1‐(hydroxy­methyl)‐3,5,7‐tri­aza‐1‐azoniatri­cyclo­[3.3.1.1^3,7]­decane cations form one O—H⃛⁻O—S [O⃛O = 2.628 (2) Å and O—H⃛O = 176°] and three C—H⃛⁻O—S [C⃛O = 3.359 (2)–3.380 (2) Å and C—H⃛O = 148–155°] interactions to neighboring sulfonate groups.     

Bis[tris(2,2′‐bipyridyl‐κ2N,N′)cobalt(II)] cyclo‐tetravanadate undecahydrate

The title compound, [Co(C₁₀H₈N₂)₃]₂[V₄O₁₂]·11H₂O, is composed of two symmetry‐related cations containing octahedrally coordinated Co^II ions, a centrosymmetric [V₄O₁₂]⁴⁻ anion with an eight‐membered ring structure made up of four VO₄ tetrahedra, and 11 solvent water molecules. The Co^II cations and vanadate anions are isolated and build cation and anion layers, respectively. In addition, the title compound exhibits a three‐dimensional network through intra‐ and intermolecular hydrogen‐bond interactions between water molecules and O atoms of the anions, and the crystal structure is stabilized mainly by hydrogen bonds.     

Synthese,Kristallstruktur und Eigenschaften der käfigartigen,sechsbasigen Säure P12S12N8(NH)6 · 14 H2O sowie ihrer Salze Li6[P12S12N14] · 26 H2O, (NH4)6[P12S12N14] · 10 H2O und K6[P12S12N14] · 8 H2O

Syntheses, Crystal Structure, and Properties of the Cage‐like, Hexaacidic P₁₂S₁₂N₈(NH)₆ · 14 H₂O and its Salts Li₆[P₁₂S₁₂N₁₄] · 26 H₂O, (NH₄)₆[P₁₂S₁₂N₁₄] · 10 H₂O, and K₆[P₁₂S₁₂N₁₄] · 8 H₂O The cage‐like acid P₁₂S₁₂N₈(NH)₆ · 14 H₂O was obtained by the reaction of KSCN with P₄S₁₀ via the formation of K₆[P₁₂S₁₂N₁₄] · 8 H₂O and subsequent ion exchange reactions in aqueous solution. Starting from the acid the salts Li₆[P₁₂S₁₂N₁₄] · 26 H₂O and (NH₄)₆[P₁₂S₁₂N₁₄] · 10 H₂O were synthesized. According to X‐ray single‐crystal structure analyses the compounds are built up by isosteric P–N cages [P₁₂S₁₂N^[3]₈N^[2]₆]^6–. Each of them is made up of twelve P₃N₃ rings, which exclusively exhibit the boat conformation. The cages have the idealized symmetry 2/m3; P₁₂S₁₂N₈(NH)₆ · 14 H₂O: P1, a = 1119.11(7), b = 1123.61(7), c = 1125.80(6) pm, α = 80.186(4), β = 60.391(4), γ = 60.605(4)°, Z = 1; Li₆[P₁₂S₁₂N₁₄] · 26 H₂O: Fm3, a = 1797.4(1) pm, Z = 4; (NH₄)₆[P₁₂S₁₂N₁₄] · 10 H₂O: P6₃, a = 1153.2(1), c = 2035.6(2) pm, Z = 2; K₆[P₁₂S₁₂N₁₄] · 8 H₂O: R3c, a = 1142.37(5), c = 6009.6(3) pm, Z = 6. In the crystal the cages of the acid are crosslinked via hydrate molecules by hydrogen bonds. The cations in the salts show a high‐mobility and are located between the cages.     

Synthesis,structural characterization,and properties of two new polyoxovanadates based on decavanadate [V10O28]6−

Two new decavanadate metal compounds, [Co(pyim)₃]₂[V₁₀O₂₈]·7H₂O (1) and [Ni(pyim)₃]₂[H₂V₁₀O₂₈]·4H₂O (2) (pyim?=?2-(2-pyridyl)-imidazole), have been synthesized under hydrothermal conditions and characterized by elemental analysis, single-crystal X-ray diffraction analysis, infrared spectra, powder X-ray diffraction analysis, and thermogravimetric analysis. Crystallographic analysis reveals that 1 is constructed from [V₁₀O₂₈]^6?, metal cation [Co(pyim)₃]³⁺, and water. [V₁₀O₂₈]^6? clusters are connected by waters through O–H?O hydrogen bonds to form a sheet structure which is further connected by N–H?O hydrogen bonds to form a 3-D supermolecular framework. In 2, although [Ni(pyim)₃]²⁺ is similar to [Co(pyim)₃]³⁺ in 1, the M?O cluster anion is protonated [H₂V₁₀O₂₈]^4?.     

Crystal structure and spectroscopic behavior of three new tris-oxalatoferrate(III) salts

A new general synthetic procedure for preparation of Na₃[Fe(C₂O₄)₃]·5H₂O (1), Rb₃[Fe(C₂O₄)₃]·3H₂O (2), and Cs₃[Fe(C₂O₄)₃]·2H₂O (3) was developed. The crystal structures of these salts have been determined by single crystal X-ray diffraction. Salt 1 crystallizes in the monoclinic space group C2/c with Z = 8, salt 2 in P2₁/c with Z = 4, and salt 3 in P2₁/n with Z = 4. The three new salts and K₃[Fe(C₂O₄)₃]·3H₂O, prepared for comparative purposes, were further characterized by infrared and ⁵⁷Fe-Mössbauer spectroscopy. These spectra are discussed in comparison with those of related oxalato complexes.