Hydrate isomerism in [Cu(en)2(H2O)1.935]2[Fe(CN)6]·4H2O

The title compound, bis[di­aqua­bis­(ethyl­enedi­amine‐κ²N,N′)copper(II)­] hexa­cyano­iron(II) tetrahydrate, [Cu(C₂H₈N₂)₂(H₂O)_1.935]₂[Fe(CN)₆]·4H₂O, was crystallized from an aqueous reaction mixture initially containing CuSO₄, K₃[Fe(CN)₆] and ethyl­enedi­amine (en) in a 3:2:6 molar ratio. Its structure is ionic and is built up of two crystallographically different cations, viz. [Cu(en)₂(H₂O)₂]²⁺ and [Cu(en)₂(H₂O)_1.87]²⁺, there being a deficiency of aqua ligands in the latter, [Fe(CN)₆]⁴⁻ anions and disordered solvent water mol­ecules. All the metal atoms lie on centres of inversion. The Cu atom is octahedrally coordinated by two chelate‐bonded en mol­ecules [mean Cu—N = 2.016 (2) Å] in the equatorial plane, and by axial aqua ligands, showing very long distances due to the Jahn–Teller effect [mean Cu—O = 2.611 (2) Å]. In one of the cations, significant underoccupation of the O‐atom site is observed, correlated with the appearance of a non‐coordinated water mol­ecule. This is interpreted as the partial contribution of a hydrate isomer. The [Fe(CN)₆]⁴⁻ anions form quite regular octahedra, with a mean Fe—C distance of 1.913 (2) Å. The dominant intermolecular interactions are cation–anion O—H⋯N hydrogen bonds and these inter­actions form layers parallel to (001).     

Double complexes [Co(NH3)5(H2O)]2[Zr3F18]·6H2O and [Co(NH3)6]2[Zr3F18]·6H2O

The structures of orthorhombic bis[pentaammineaquacobalt(III)] tetra‐μ₂‐fluorido‐tetradecafluoridotrizirconium(IV) hexahydrate (space group Ibam), [Co(NH₃)₅(H₂O)]₂[Zr₃F₁₈]·6H₂O, (I), and bis[hexaamminecobalt(III)] tetra‐μ₂‐fluorido‐tetradecafluoridotrizirconium(IV) hexahydrate (space group Pnna), [Co(NH₃)₆]₂[Zr₃F₁₈]·6H₂O, (II), consist of complex [Co(NH₃)_x(H₂O)_y]³⁺ cations with either m [in (I)] or and 2 [in (II)] symmetry, [Zr₃F₁₈]⁶⁻ anionic chains located on sites with 222 [in (I)] or 2 [in (II)] symmetry, and water molecules.     

[Mn(H2O)2]4[HNC5H4(COO)]2[C6H2(COO)4]2·4H2O — Ein dreidimensionales Koordinationspolymer mit Gastwassermolekülen in kanalartigen Hohlräumen

[Mn(H₂O)₂]₄[HNC₅H₄(COO)]₂[C₆H₂(COO)₄]₂·4H₂O — A Three‐dimensional Coordination Polymer with Guest Water Molecules in Channel‐like Voids Single crystals of [Mn(H₂O)₂]₄[HNC₅H₄(COO)]₂[C₆H₂(COO)₄]₂·4H₂O have been prepared in aqueous solution at 55 °C. Space group P1¯ (no. 2), a = 999.7(2), b = 1314.4(2), c = 1645.8(2) pm, α = 101.096(8)°, β = 92.796(14)°, γ = 96.03(2)°, V = 2.1053(5) nm³, Z = 2. There are four unique Mn²⁺ which are coordinated in a distorted, octahedral manner by two water molecules, three oxygen atoms of the pyromellitate anions and one oxygen atom of isonicotinic acid (Mn—O 208.6(2) — 227.3(3) pm). The connection of Mn²⁺ and [C₆H₂(COO)₄]^4— yields a three‐dimensional coordination polymer with two different, channel‐like voids extending parallel to [110]. The first channel accomodates water molecules, the second channel is filled by isonicotinic acid molecules. Thermogravimetric analysis in air revealed that the loss of water of crystallisation occurs in two steps between 97 and 200 °C. The dehydrated sample was stable between 200 and 340 °C. Further decomposition yielded Mn₃O₄.     

Crystal Structures of [Mn2(H2O)4(phen)2(C4H4O4)2] · 2 H2O and [Mn(phen)2(H2O)2][Mn(phen)2(C4H4O4)](C4H4O4) · 7 H2O

Reactions of 1,10‐phenanthroline monohydrate, Na₂C₄H₄O₄ · 6 H₂O and MnSO₄ · H₂O in CH₃OH/H₂O yielded a mixture of [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] · 2 H₂O ( 1 ) and [Mn(phen)₂(H₂O)₂][Mn(phen)₂(C₄H₄O₄)](C₄H₄O₄) · 7 H₂O ( 2 ). The crystal structure of 1 (P1 (no. 2), a = 8.257(1) Å, b = 8.395(1) Å, c = 12.879(2) Å, α = 95.33(1)°, β = 104.56(1)°, γ = 106.76(1)°, V = 814.1(2) ų, Z = 1) consists of the dinuclear [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] molecules and hydrogen bonded H₂O molecules. The centrosymmetric dinuclear molecules, in which the Mn atoms are octahedrally coordinated by two N atoms of one phen ligand and four O atoms from two H₂O molecules and two bis‐monodentate succinato ligands, are assembled via π‐π stacking interactions into 2 D supramolecular layers parallel to (101) (d(Mn–O) = 2.123–2.265 Å, d(Mn–N) = 2.307 Å). The crystal structure of 2 (P1 (no. 2), a = 14.289(2) Å, b = 15.182(2) Å, c = 15.913(2) Å, α = 67.108(7)°, β = 87.27(1)°, γ = 68.216(8)°, V = 2934.2(7) ų, Z = 2) is composed of the [Mn(phen)₂(H₂O)₂]²⁺ cations, [Mn(phen)₂(C₄H₄O₄)] complex molecules, (C₄H₄O₄)^2– anions, and H₂O molecules. The (C₄H₄O₄)^2– anions and H₂O molecules form 3 D hydrogen bonded network and the cations and complex molecules in the tunnels along [001] and [011], respectively, are assembled via the π‐π stacking interactions into 1 D supramolecular chains. The Mn atoms are octahedrally coordinated by four N atoms of two bidentate chelating phen ligands and two water O atoms or two carboxyl O atoms (d(Mn–O) = 2.088–2.129 Å, d(Mn–N) = 2.277–2.355 Å). Interestingly, the succinato ligands in the complex molecules assume gauche conformation bidentately to chelate the Mn atoms into seven‐membered rings.     

Hexachloroplatinates of the Lanthanides: Syntheses and Thermal Decomposition of [M(NO3)2(H2O)6]2[PtCl6]·2H2O (M = La,Pr) and [M(NO3)(H2O)7][PtCl6]·4H2O (M = Gd,Dy)

The reaction of the nitrates M(NO₃)₃·6H₂O (M = La, Pr) and (H₃O)₂PtCl₆ led to yellow single crystals of [M(NO₃)₂(H₂O)₆]₂[PtCl₆]·2H₂O (M = La, Pr) (monoclinic, P2₁/c, Z = 2, La/Pr: a = 697.4(3)/695.5(1), b = 1654.5(1)/1652.5(2), c = 1317.7(6)/1318.5(3) pm, β = 93.97°(7)/93.93°(2), R_all = 0.0169/0.0659) while the reaction of M(NO₃)₃·5H₂O (M = Gd, Dy) and (H₃O)₂PtCl₆ yielded yellow single crystals of [M(NO₃)(H₂O)₇][PtCl₆]·4H₂O (monoclinic, P2₁/n, Z = 4, Gd/Dy: a = 838.72(3)/838.40(2), b = 2131.98(6)/2139.50(7), c = 1142.63(3)/1143.10(3) pm, β = 95.670(4)/95.698(3), R_all = 0.0475/0.0337). The crystal structures consist of octahedral [PtCl₆]^2? anions and complex [M(NO₃)₂(H₂O)₆]₂⁺ and [M(NO₃)(H₂O)₇]²⁺ cations, respectively. The thermal decomposition of both types of compounds leads via various steps to elemental platinum and the oxide chlorides MOCl (M = La, Pr, Gd, Dy).     

Heteronukleare Metallatomcluster der Typen X4−n[SnM(CO)4P(C6H5)3]n und M2(CO)8 [μ-Sn(X)M (CO)4P(C6H5)3]2 aus Umsetzungen von SnX2 mit M2(CO)8[P(C6H5)3]2 (X = Halogen; M = Mn,Re; n = 2, 3)

Heteronuclear Metal Atom Clusters of the Types X_4?n[SnM(CO)₄P(C₆H₅)₃]_n and M₂(CO)₈[μ-Sn(X)M(CO)₄P(C₆H₅)₃]₂ by Reaction of SnX₂ with M₂(CO)₈[P(C₆H₅)₃]₂ (X = Halogene; M = Mn, Re; n = 2, 3) The compounds of the both types X_4?n[SnM(CO)₄P(C₆H₅)₃]_n (n = 3; M = Mn; X = F, Cl, Br, I. n = 2: M = Mn, Re; X = Cl, Br, I) and M₂(CO)₈[μ-Sn(X)M(CO)₄P(C₆H₅)₃]₂ (M = Mn; X = Cl, I. M = Re; X = Cl, Br, I) are prepared by reaction of SnX₂ with M₂(CO)₈[P(C₆H₅)₃]₂ (M = Mn, Re). Their IR frequencies are assigned. In Re₂(CO)₈[μ-Sn(Cl)Re(CO)₄P(C₆H₅)₃]₂ the central molecule fragment contains a planar Re₂Sn₂ rhombus with a transannular Re? Re bond of 316.0(2) pm. Each of the Sn^IV atoms is connected with the terminal ligands Cl and Re(CO)₄P(C₆H₅)₃. These ligands are in transposition with respect to the Re₂Sn₂ ring. The mean values for the remaining bond distances (pm) are: Sn? Re = 274.0(3); Sn? Cl = 243(1), Re? C = 176(5), Re? P = 242.4(9), C? O = 123(5). The factors with an influence on the geometrical shape of such M₂Sn₂ rings (M = transition metal) are discussed.     

Cs2.91Na1.34Fe3+0.25[Fe3O(SO4)6(H2O)3]·5H2O,a member of the Maus's salt family

The title compound, tricaesium sodium iron(III) μ₃‐oxido‐hexa‐μ₂‐sulfato‐tris[aquairon(III)] pentahydrate, Cs_2.91Na_1.34Fe³⁺_0.25[Fe₃O(SO₄)₆(H₂O)₃]·5H₂O, belongs to the family of Maus's salts, K₅[Fe₃O(SO₄)₆(H₂O)₃]·6H₂O, which is based on the triaqua‐μ₃‐oxido‐hexa‐μ‐sulfato‐triferrate(III) anion, [Fe₃O(SO₄)₆(H₂O)₃]⁵⁻, with Fe in a characteristically distorted octahedral coordination environment, sharing a common corner via an oxide O atom. Cs in four different cation sites, Na in three different cation sites and five water molecules link the anions in three dimensions and set up a crystal structure in which those parts parallel to (001) and within 0.05 < z < 0.95 have a distinct trigonal pseudosymmetry, whereas the cation arrangement and bonding near z∼ 0 generate a clear‐cut noncentrosymmetric polar edifice with the monoclinic space group C2. The structure shows some cation disorder in the region near z ∼ , where one Na atom in octahedral coordination is partly substituted by Fe³⁺, and a Cs atom is substituted by small amounts of Na on a separate nearby site. One Na atom, located on a twofold axis at z = 0 and tetrahedrally coordinated by four sulfate O atoms of two [Fe₃O(SO₄)₆(H₂O)₃]⁵⁻ units, plays a key role in generating the noncentrosymmetric structure. Three of the seven different cation sites are on twofold axes (one Na⁺ site and two Cs⁺ sites), and all other atoms of the structure are in general positions.     

Solvothermal synthesis,crystal structure and properties of Mn2(tren)3[Mo2O2S6]2·1.3H2O exhibiting the new polymeric [Mn2(tren)3] n 4+ chain

The novel oxothiomolybdate Mn₂(tren)₃[Mo₂O₂S₆]₂·1.3H₂O [tren = tris(2-aminoethyl)amine], synthesized under solvothermal conditions, consists of one-dimensional novel [Mn₂(tren)₃] _n ⁴⁺ chains and discrete [Mo₂O₂S₆]^2– anions. There are two crystallographically independent chains and four [Mo₂O₂S₆]^2– anions in the asymmetric unit. Each Mn atom in the cationic chains is sixfold coordinated by N atoms of the chelating tren molecules. Two of the four crystallographically independent Mn atoms are tridentately coordinated by two tren molecules, whereas the other two are coordinated tetradentately by one tren molecule and monodentately by the remaining primary amino groups from the tren molecules that act as tridentate ligands. The tren ligand bonding modes lead to the formation of the polymeric [Mn₂(tren)₃] _n ⁴⁺ chain. One of the four Mn atoms is in the unusual trigonal prismatic coordination state with six surrounding N atoms.     

Solvothermal Synthesis and Crystal Structures of Two Thioantimonate(V) Compounds with the [SbS4]3— Anion Acting as a Monodentate Ligand: [Mn(C6H18N4)(C6H19N4)]SbS4 and [Mn(C6H14N2)3]2[Mn(C6H14N2)2(SbS4)2]·6H2O

The two novel thioantimonate(V) compounds [Mn(C₆H₁₈N₄)(C₆H₁₉N₄)]SbS₄ ( I ) and [Mn(C₆H₁₄N₂)₃][Mn(C₆H₁₄N₂)₂(SbS₄)₂]·6H₂O ( II ) were synthesized under solvothermal conditions by reacting elemental Mn, Sb and S in the stoichiometric ratio in 5 ml tris(2‐aminoethyl)amine (tren) at 140 °C or chxn (trans‐1, 2‐diaminocyclohexane, aqueous solution 50 %) at 130 °C. Compound I crystallises in the triclinic space group P1¯, a = 9.578(2), b = 11.541(2), c = 12.297(2)Å, α = 62.55(1), β = 85.75(1), γ = 89.44(1)°, V = 1202.6(4)ų, Z = 2, and II in the monoclinic space group C2/c, a = 32.611(2), b = 13.680(1), c = 19.997(1)Å, β = 117.237(5)°, V = 7931.7(8)ų, Z = 4. In I the Mn²⁺ cation is surrounded by one tetradentate tren molecule, one protonated tren acting as a monodentate ligand and a monodentate [SbS₄]^3— anion yielding a distorted octahedral environment. In II one unique Mn²⁺ ion is in an octahedral environment of three bidentate chxn molecules and the second independent Mn²⁺ ion is coordinated by two chxn ligands and two monodentate [SbS₄]^3— units leading to a distorted octahedral surrounding. The compounds were investigated and characterized with thermal and spectroscopic methods.     

Strukturen und thermische Zersetzung von enH2(H3O)[AlF6] und enH2[AlF5(H2O)]

Structures and Thermal Decomposition of enH₂(H₃O)[AlF₆] and enH₂[AlF₅(H₂O)] By precipitation with ethylene diamine (en) from a hydrofluoric acid solution of aluminium enH₂(H₃O)[AlF₆] is formed. It crystallizes in the orthorhombic space group Pnma, a = 1084.9(1), b = 1079.4(1), c = 682.0(1) pm, R = 0.032. H₃O⁺ cations and [AlF₆]^3– anions are connected via strong H bonds to layers which are further linked to a 3 D network by H bonds from the enH₂²⁺ cations. By recrystallization from water or precipitation from a less acid solution enH₂[AlF₅(H₂O)] is formed, which crystallizes monoclinic in the space group P2₁ (a = 660.0(1), b = 563.5(1), c = 994.4(2) pm, β = 98.44(3)°, R = 0.029). The [AlF₅(H₂O)]^2– anions are linked by strong O–H…F bonding to form ‘einer-double chains' interconnected again via the enH₂²⁺ cations to a 3 D framework. Thermoanalytical investigations show that enH₂[AlF₅(H₂O)], by loss of water above 150 °C, as well as enH₂(H₃O)[AlF₆], by loss of water and HF above 120 °C, transform to enH₂AlF₅. The subsequent decomposition goes over NH₄⁺ containing intermediates towards β-AlF₃. Before decomposition the oxonium fluoroaluminate reveals a reversible phase transition at 99 °C.     

K2[Mo2O4(C2O4)2(H2O)2]·3H2O

The crystal and molecular structure of dipotassium di‐μ‐oxo‐bis[aqua(oxalato‐O¹,O²)oxomolybdenum(III)] trihydrate, K₂­[Mo₂O₄(C₂O₄)₂(H₂O)₂]·3H₂O, has been determined from X‐ray diffraction data. In the dimeric anion, which has approximate twofold symmetry, each Mo atom is in a distorted octahedral coordination, being bonded to one terminal oxo‐O atom, two bridging O atoms, two O atoms from the oxalato ligand and one from the water mol­ecule. Bond lengths trans to the multiple‐bonded terminal oxo ligand are larger than those in the cis position, confirming the trans influence as a generally valid rule.     

Das erste Vanadium(III)‐Borophosphat: Darstellung und Kristallstruktur von CsV3(H2O)2[B2P4O16(OH)4]

The First Vanadium(III) Borophosphate: Synthesis and Crystal Structure of CsV₃(H₂O)₂[B₂P₄O₁₆(OH)₄] CsV₃(H₂O)₂[B₂P₄O₁₆(OH)₄] was prepared under mild hydrothermal conditions (T = 165 °C) from mixtures of CsOH_(aq), VCl₃, H₃BO₃, and H₃PO₄ (molar ratio 1 : 1 : 1 : 2). The crystal structure was determined by X‐ray single crystal methods (monoclinic; space group C2/m, No. 12): a = 958.82(15) pm, b = 1840.8(4) pm, c = 503.49(3) pm; β = 110.675(4)°; Z = 2. The anionic partial structure contains oligomeric units [BP₂O₈(OH)₂]^5–, which are built up by a central BO₂(OH)₂ tetrahedron and two PO₄ tetrahedra sharing common corners. V^III is octahedrally coordinated by oxygen of adjacent phosphate tetrahedra and OH groups of borate tetrahedra as well as oxygen of phosphate tetrahedra and H₂O molecules, respectively (coordination octahedra VO₄(OH)₂ and VO₄(H₂O)₂). The oxidation state +3 for vanadium was confirmed by measurements of the magnetic susceptibility. The trimeric borophosphate groups are connected via vanadium centres to form layers with octahedra‐tetrahedra ring systems, which are likewise linked via V^III‐coordination octahedra. Overall, a three‐dimensional framework constructed from VO₄(OH)₂ and VO₄(H₂O)₂ octahedra as well as BO₂(OH)₂ and PO₄ tetrahedra results. The structure contains channels running along [001], which are occupied by Cs⁺ in a distorted octahedral coordination (CsO₄(H₂O)₂).     

Hydrothermal Synthesis and Crystal Structures of Na2Be3(SeO3)4·H2O and Cs2[Mg(H2O)6]3(SeO3)4

The selenites, Na₂Be₃(SeO₃)₄ · H₂O and Cs₂[Mg(H₂O)₆]₃(SeO₃)₄, were synthesized under hydrothermal conditions. The crystal structures of Na₂Be₃(SeO₃)₄ · H₂O and Cs₂[Mg(H₂O)₆]₃(SeO₃)₄ were determined by single‐crystal X‐ray diffractions. Na₂Be₃(SeO₃)₄ · H₂O crystallizes in the triclinic space group P1 (no. 2) with unit cell parameters a = 4.8493(9), b = 12.013(2), c = 12.077(2) Å, and Z = 2, whereas Cs₂[Mg(H₂O)₆]₃(SeO₃)₄ crystallizes in the monoclinic space group C2/m (no. 12) with lattice cell parameters a = 12.596(6), b = 7.297(4), c = 16.914(8) Å, and Z = 2. Na₂Be₃(SeO₃)₄ · H₂O features a three‐dimensional open framework structure formed by BeO₄ tetrahedra and SeO₃ trigonal pyramids. Na cations and H₂O molecules are located in different tunnels. Cs₂[Mg(H₂O)₆]₃(SeO₃)₄ has a structure composed of isolated [Mg(H₂O)₆] octahedra and SeO₃ trigonal pyramids interacted by hydrogen bonds, and Cs cations are resided in‐between. Both compounds were characterized by thermogravimetric analysis and FT‐IR spectroscopy.     

[Mn(en)]3[Cr(CN)6]2⋅4 H2O: A Three-Dimensional Dimetallic Ferrimagnet (Tc=69 K) with a Defective Cubane Unit

The first modified analogue of the A^II₃[B^III(CN)₆]₂⋅x H₂O type of Prussian-Blue, the title compound, has a three-dimensional network structure extended by Cr^III-CN-Mn^II linkages, which is based on a defective cubane unit comprising three Cr and four Mn ions (see structure), and shows ferrimagnetic ordering below 69 K.     

Formation of Cocrystals between Alkali Triazine Tricarboxylates and Cyanuric Acid – Reactivity Considerations and Structural Characterization of the Adduct Phases M3[C3N3(CO2)3][C3N3O3H3]·H2O (M = K,Rb)

The reactivity of cyanuric acid towards alkali triazinetricarboxylates was investigated and the first triazine‐triazine adduct phases comprising alkali metal ions were synthesized and characterized by single‐crystal X‐ray diffraction and thermal analysis. An investigation of the reaction between the alkali triazine tricarboxylates M₃[C₃N₃(CO₂)₃] · xH₂O (M = Li, Na, K, Rb, Cs) and cyanuric acid showed that the degree of ion transfer from triazine tricarboxylate to cyanuric acid increases gradually from the lithium to the cesium salt reflecting an increasing basicity of the triazine tricarboxylates.The reaction of potassium and rubidium triazine tricarboxylate dihydrate with cyanuric yielded the novel co‐crystalsK₃[C₃N₃(CO₂)₃][C₃N₃O₃H₃] · H₂O ( 3a ) and Rb₃[C₃N₃(CO₂)₃][C₃N₃O₃H₃] · H₂O ( 3b ). In comparison to metal free triazine‐triazine adduct phases in these compounds the assembly of molecules in the crystal is mainly determined by Coulomb interactions and only to a certain degree by hydrogen bonds and dispersive interactions. In the crystal the s‐triazine units exhibit a layered structure with triazine tricarboxylate and isocyanuric acid being arranged in zigzag strands within the layers and stacked in columns perpendicular to the layers. Thermal analysis revealed a quite weak cohesion between triazine tricarboxylate and cyanuric acid upon heating.     

M(H2O)2(4,4′‐bipy)[C6H4(COO)2]·2H2O (M = Mn2+, Co2+) – Zwei isotype Koordinationspolymere mit Schichtstruktur

M(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]·2H₂O (M = Mn²⁺, Co²⁺) – Two Isotypic Coordination Polymers with Layered Structure Monoclinic single crystals of Mn(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]·2H₂O ( 1 ) and Co(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]· 2H₂O ( 2 ) have been prepared in aqueous solution at 80 °C. Space group P2/n (no. 13), Z = 2; 1 : a = 769.20(10), b = 1158.80(10), c = 1075.00(10) pm, β = 92.67(2)°, V = 0.9572(2) nm³; 2 : a = 761.18(9), b = 1135.69(9), c = 1080.89(9) pm, β = 92.276(7)°, V = 0.9337(2) nm³. M²⁺ (M = Mn, Co), which is situated on a twofold crystallographic axis, is coordinated in a moderately distorted octahedral fashion by two water molecules, two oxygen atoms of the phthalate anions and two nitrogen atoms of 4,4′‐biypyridine ( 1 : M–O 219.5(2), 220.1(2) pm, M–N 225.3(2), 227.2(2) pm; 2 : Co–O 212.7(2), 213.7(2) pm, Co–N 213.5(3), 214.9(3) pm). M²⁺ and [C₆H₄(COO)₂)]^2? build up chains, which are linked by 4,4′‐biyridine molecules to yield a two‐dimensional coordination polymer with layers parallel to (001).Thermogravimetric analysis in air of 1 indicated a loss of water of crystallization between 154 and 212 °C and in 2 between 169 and 222 °C.     

Hydrothermal synthesis and structural determination of a three-dimensional microporous iron(III)phosphate: [H3N(CH2)4NH3]3[Fe8(HPO4)12(PO4)2(H2O)6]

A new microporous iron (III) phosphate, [H₃N(CH₂)₄NH₃]₃[Fe₈(HPO₄)₁₂(PO₄)₂(H₂O)₆], has been prepared using low temperature hydrothermal methods and characterized by single-crystal X-ray diffraction, EDAX, infrared spectroscopy, thermogravimetric analysis and bond valence sums. The title compound crystallizes as light pink hexagonal-shaped tabs in the centrosymmetric hexagonal space group 3¯ (No.147) with a = b = 13.495(2) Å, c = 9.396(2) Å, V = 1481.9(4) ų and Z = 4 with R/R_w = 0.044/0.048. The compound exhibits a complicated three-dimensional microporous structure with quaternary ammonium ions acting as a template for the framework. It is similar to previously reported [HN(CH₂CH₂)₃NH]₃[Fe₈(HPO₄)₁₂(PO₄)₂(H₂O)₆].     

IV Dodekaedrische [Mo(CN)8]‐Koordination in den cyanoverbrückten Cobalt‐ und Nickel‐Amminkomplexen MII2(NH3)8[Mo(CN)8] · 1,5 H2O (MII = Co,Ni) und Ni2(NH3)9[Mo(CN)8] · 2 H2O

Crystal Structures of Octacyanomolybdates(IV). IV Dodecahedral [Mo(CN)₈] Coordination of the Cyano‐Bridged Cobalt and Nickel Ammin Complexes M^II₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (M^II = Co, Ni) and Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O At single crystals of the hydrated cyano complexes Co₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 910.0(4), b = 1671(2), c = 1501(1) pm, β = 93.76(6)°) and Ni₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 899.9(9), b = 1654.7(4), c = 1488(1) pm, β = 94.01°), isostructurally crystallizing in space group P2₁/c, Z = 4, and of trigonal Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O (a = 955.1(1), c = 2326.7(7) pm, P3₁, Z = 3), X‐ray structure determinations were performed at 168 resp. 153 K. The [Mo(CN)₈]^4– groups of the three compounds, prepared at about 275 K and easily decomposing, show but slightly distorted dodecahedral coordination (mean distances Mo–C: 216.3, 215.4 and 216.1 pm). Within the monoclinic complexes the anions twodimensionally form cyano bridges to the ammin cations [M(NH₃)₄]²⁺ and are connected with the resulting [MN₆] octahedra (Co–N: 215.1 pm, Ni–N: 209.8 pm) into strongly puckered layers. The trigonal complex exhibits a chain structure, as one [Ni(NH₃)₅]²⁺ cation is only bound as terminal octahedron (Ni–N: 212.0 pm). Details and the influence of hydrogen bridges are discussed.     

Correlation between Solution and the Solid State: The pH Dependent Composition in the Ternary System [Co(H2O)6]2+ or [Ni(H2O)6]2+/Piperazine/Phosphate

The protolytic equilibria of piperazine (C₄H₁₀N₂) and phosphate have been investigated in the presence of cobalt or nickel chloride or nitrate by potentiometric titrations between pH 2 and 8. Potentiometric titrations suggest the presence of [M²⁺(H₂O)₅(C₄H₁₁N₂⁺)]³⁺ and [M²⁺(H₂O)₅(C₄H₁₀N₂)]²⁺ in solution with stability constants logK of 3.1 and 3.8 for M = Co and 3.1 and 3.6 for M = Ni, respectively. Crystallization experiments were then conducted at selected pH values to isolate desired species from the known solution composition. Crystallization afforded [M(H₂O)₆]²⁺(C₄H₁₂N₂²⁺)(HPO₄^2—)₂ at pH 3.5 and 6.2 (M = Co, Ni), and Co₃(PO₄)₂·8H₂O at pH 10.5. No crystals with the dihydrogenphosphate anion or a metal‐bound piperazine ligand could be isolated under the reaction conditions. The solid‐state assembly in the isomorphous structures of [M(H₂O)₆](C₄H₁₂N₂)(HPO₄)₂ with M = Co and Ni is based on an extended hydrogen bonded network between the three ionic building blocks.