A chiral furocoumarin

The furocoumarin 1,2‐di­hydro‐2‐(1,2‐di­hydroxy­prop‐2‐yl)‐8H‐furo­[2,3‐h]­benzo­pyran‐8‐one crystallizes from methanol–water as the monohydrate C₁₄H₁₄O₅·H₂O. Both chiral centers have the S configuration. Both OH groups and both H atoms of the water mol­ecule form intermolecular hydrogen bonds with O?O distances in the range 2.7686 (18)–2.8717 (18) Å.     

3Mg(OH)2·MgSO4·8H2O: A Metastable Phase in the System Mg(OH)2‐MgSO4‐H2O

In the course of investigations relating to magnesia oxysulfate cement the basic magnesium salt hydrate 3Mg(OH)₂ · MgSO₄ · 8H₂O (3–1–8 phase) was found as a metastable phase in the system Mg(OH)₂‐MgSO₄‐H₂O at room temperature (the 5–1–2 phase is the stable phase) and was characterized by thermal analysis, Raman spectroscopy, and X‐ray powder diffraction. The complex crystal structure of the 3–1–8 phase was determined from high resolution laboratory X‐ray powder diffraction data [space group C2/c, Z = 4, a = 7.8956(1) Å, b = 9.8302(2) Å, c = 20.1769(2) Å, β = 96.2147(16)°, and V = 1556.84(4) ų]. In the crystal structure of the 3–1–8 phase, parallel double chains of edge‐linked distorted Mg(OH₂)₂(OH)₄ octahedra run along [–110] and [110] direction forming a pattern of crossed rods. Isolated SO₄ tetrahedra and interstitial water molecules separate the stacks of parallel double chains.     

Solubility and Crystallization in the System MgCl2–MgSO4–H2O at 50 and 75°C

The system MgCl₂–MgSO₄–H₂O has been investigated experimentally and modeled thermodynamically according to the Pitzer method at 50 and 75°C. It was found that, even when seemingly all requirements for reaching the stable thermodynamic equilibrium are fulfilled, the crystallization of higher hydrates as metastable phases is possible, and cannot be avoided in each crystallization field of a stable lower hydrate of magnesium sulfate. Crystallization of MgSO₄ · x H₂O (x = 1, 4, 6) and MgCl₂ · 6 H₂O at 50°C and of MgSO₄ · H₂O and MgCl₂ · 6 H₂O at 75°C as stable phases has been observed. Three metastable crystallization fields of MgSO₄ · x H₂O (x = 4, 6, 7) have been detected at 50°C and two of MgSO₄ · x H₂O (x = 4, 6) at 75°C. The results obtained and the contradictions existing in the literature with respect to the solubility and the crystallizing solid phases are discussed in terms of the crystal structures.     

Co(en)3[B4O5(OH)4]Cl·3H2O和[Ni(en)3][B5O6(OH)4]2·2H2O的合成、结构以及热力学性质

利用水热法合成了两种过渡金属配合物为模板剂的含水硼酸盐晶体Co(en)3[B4O5(OH)4]Cl·3H2O(1) 和 [Ni(en)3][B5O6(OH)4]2·2H2O (2),并通过元素分析、X射线单晶衍射、红外光谱及热重分析对其进行了表征。化合物1晶体结构的主要特点是在所有组成Co(en)33+, [B4O5(OH)4]2–, Cl– 和 H2O之间通过O–H…O、O–H…Cl、N–H…Cl和N–H…O四种氢键连接形成网状超分子结构。化合物2晶体结构的特点是[B5O6(OH)4]–阴离子通过O–H…O氢键连接形成沿a方向有较大通道的三维超分子骨架,模板剂[Ni(en)3]2+阳离子和结晶水分子填充在通道中。     

Poly­[[[(1,10‐phenanthroline‐κ2N,N′)­zinc(II)]‐μ3‐5‐hydroxy­isophthalato‐κ4O,O′:O′′:O′′′] monohydrate]

In the title compound, {[Zn(C₈H₄O₅)(C₁₂H₈N₂)]·H₂O}_n or {[Zn(OH‐BDC)(phen)]·H₂O}_n (where OH‐H₂BDC is 5‐hydroxy­isophthalic acid and phen is 1,10‐phenanthroline), the Zn atoms are coordinated by two N atoms from the phen ligands and by four O atoms from hydroxy­isophthalate ligands in a highly distorted octahedral geometry, with Zn—O distances in the range 2.042 (4)–2.085 (5) Å and Zn—N distances of 2.133 (5) and 2.137 (5) Å. The {[Zn(OH‐BDC)(phen)]·H₂O}_n infinite zigzag polymer forms a helical chain of [Zn₂(OH‐BDC)₂]_n units. Face‐to‐face π–π interactions (3.60–3.75 Å) occur between two phen rings belonging to the same helical chain. Consolidation of the packing structure is achieved by O—H⋯O hydrogen‐bonding interactions between the carboxyl­ate O atoms, the hydroxyl group and the water mol­ecule, forming two‐dimensional sheets.     

A Sterically Hindered Phosphonic Acid with a Hydrogen‐Bonded Cage Structure: [4‐tert‐Bu‐2,6‐Mes2‐C6H2P(O)(OH)2·H2O]4

The synthesis and molecular structure of the novel phosphonic acid 4‐tert‐Bu‐2,6‐Mes₂‐C₆H₂P(O)(OH)₂ ( 1 ) is reported. Compound 1 crystallizes in form of its monohydrate as a hydrogen‐bonded cluster ( 1·H₂O )₄ comprizing four phosphonic acid molecules (O···O 2.383(3)‐3.006(4) Å). Additionally, sterically hindered terphenyl‐substituted phosphorus compounds of the type 4‐tert‐Bu‐2,6‐Mes₂‐C₆H₂PR(O)(OH) ( 5 , R = H; 7 , R = O₂CC₆H₄‐3‐Cl; 9 , R = OEt) were prepared, which all show dimeric hydrogen‐bonded structures with O···O distances in the range 2.489(2)–2.519(3) Å. Attempts at oxidizing 5 using H₂O₂, KMnO₄, O₃, or Me₃NO in order to give 1 failed. Crystallization of 5 in the presence of Me₃NO gave the novel hydrogen bonded aggregate 4‐tert‐Bu‐2,6‐Mes₂‐C₆H₂PH(O)(OH)·ONMe₃ ( 6 ) showing an O–H···O distance of 2.560(4) Å.     

Assembly of a Novel Dumbbell‐type Dinuclear Copper(II) Complex: Synthesis,Structure and Properties

A new dumbbell‐type 4,4′‐bipy‐bridged dinuclear copper(II) complex, [Cu₂(4,4′‐bipy)L₂(H₂O)₂](ClO₄)₄ · 8CH₃OH · 10H₂O, where L = 1‐[bis(3‐aminopropyl)amino]‐2‐ propanol and bipy = bipyridine, has been synthesized and characterized, X‐ray crystallographic analysis shows that the [Cu₂(4,4′‐bipy)L₂(H₂O)₂]⁴⁺ cations and water molecules generate layer structures extending parallel to bc planes through hydrogen bonding interactions of O–H ··· O and C–H ··· O. The layers are also connected by hydrogen bonding interactions involving methanol, water, and perchlorate anions. These interactions lead to the formation of rectangular channels of 12.3 Å × 6.0 Å along the crystallographic c axis. Perchlorate anions fill in each channel in a sandwich‐like packing mode, they are joined with the adjacent layers by water heptamers. Magnetic susceptibility measurements show that the magnetic exchange interaction is weak although it has a regular π‐type electron transfer pathway. Furthermore, the electrochemical and thermogravimetric properties of the complex were also investigated.     

Cobalt(II) and nickel(II) complexes of quinoline‐2‐carboxyl­ate

The title complexes, trans‐di­aqua­bis­(quinoline‐2‐carboxyl­ato‐κ²N,O)­cobalt(II)–water–methanol (1/2/2), [Co(C₁₀H₆NO₂)₂(H₂O)₂]·2CH₄O·2H₂O, and trans‐di­aqua­bis­(quinoline‐2‐car­box­yl­ato‐κ²N,O)­nickel(II)–water–methanol (1/2/2), [Ni(C₁₀H₆NO₂)₂(H₂O)₂]·2CH₄O·2H₂O, are isomorphous and contain Co^II and Ni^II ions at centers of inversion. Both complexes have the same distorted octahedral coordination geometry, and each metal ion is coordinated by two quinoline N atoms, two carboxyl­ate O atoms and two water O atoms. The quinoline‐2‐carboxyl­ate ligands lie in trans positions with respect to one another, forming the equatorial plane, with the two water ligands occupying the axial positions. The complex mol­ecules are linked together by hydrogen bonding involving a series of ring patterns which include the uncoordinated water and methanol mol­ecules.     

Five solvates of a multicomponent pharmaceutical salt formed by berberine and diclofenac

A multicomponent pharmaceutical salt formed by the isoquinoline alkaloid berberine (5,6‐dihydro‐9,10‐dimethoxybenzo[g]‐1,3‐benzodioxolo[5,6‐a]quinolizinium, BBR) and the nonsteroidal anti‐inflammatory drug diclofenac {2‐[2‐(2,6‐dichloroanilino)phenyl]acetic acid, DIC} was discovered. Five solvates of the pharmaceutical salt form were obtained by solid‐form screening. These five multicomponent solvates are the dihydrate (BBR–DIC·2H₂O or C₂₀H₁₈NO₄⁺·C₁₄H₁₀Cl₂NO₂^?·2H₂O), the dichloromethane hemisolvate dihydrate (BBR–DIC·0.5CH₂Cl₂·2H₂O or C₂₀H₁₈NO₄⁺·C₁₄H₁₀Cl₂NO₂^?·0.5CH₂Cl₂·2H₂O), the ethanol monosolvate (BBR–DIC·C₂H₅OH or C₂₀H₁₈NO₄⁺·C₁₄H₁₀Cl₂NO₂^?·C₂H₅OH), the methanol monosolvate (BBR–DIC·CH₃OH or C₂₀H₁₈NO₄⁺·C₁₄H₁₀Cl₂NO₂^?·CH₃OH) and the methanol disolvate (BBR–DIC·2CH₃OH or C₂₀H₁₈NO₄⁺·C₁₄H₁₀Cl₂NO₂^?·2CH₃OH), and their crystal structures were determined. All five solvates of BBR–DIC (1:1 molar ratio) were crystallized from different organic solvents. Solvent molecules in a pharmaceutical salt are essential components for the formation of crystalline structures and stabilization of the crystal lattices. These solvates have strong intermolecular O…H hydrogen bonds between the DIC anions and solvent molecules. The intermolecular hydrogen‐bond interactions were visualized by two‐dimensional fingerprint plots. All the multicomponent solvates contained intramolecular N—H…O hydrogen bonds. Various π–π interactions dominate the packing structures of the solvates.     

Solid–Liquid Metastable Phase Equilibria in the Ternary System (MgCl<Subscript>2</Subscript> + MgSO<Subscript>4</Subscript> + H<Subscript>2</Subscript>O) at 323.15 K

The solubilities and the densities in the aqueous ternary system (MgCl₂ + MgSO₄ + H₂O) at 323.15 K were determined by the isothermal evaporation method. The phase diagram was drawn for this system at 323.15 K. The phase diagram consists of two invariant points, three univariant curves, and three crystallization regions corresponding to bischofite (MgCl₂ · 6H₂O), tetrahydrate (MgSO₄ · 4H₂O) and hexahydrite (MgSO₄ · 6H₂O). Neither double salts nor solid solution was found. Based on the Pitzer and Harvie–Weare (HW) model, the solubility equilibrium constants for the salts were fitted with the solubilities in this research work, and the solubilities of the ternary system at 323.15 K were calculated. Comparisons between the calculated and measured solubilities show that the predicted data agree well with the experimental results.     

Orthotelluric Acid as Substitute for Crystal‐Water: Syntheses and Crystal Structure of the Co‐crystallate [Te(OH)6 · 2 Adenine · 4 H2O] and the Disodium Ditellurate(VI) Aggregate {[Te2O2(OH)6(ONa)2]2[NaOH · 12.5 H2O]}

Supramolecular aspects on Te(OH)₆ as substitute for crystal‐water in adenine hydrate complexes and the first disodium ditellurate(VI) are reported. The co‐crystallate [Te(OH)₆ · 2 adenine · 4 H₂O] ( 1 ) has been prepared in 41% yield from the 1 : 1 mixing of Te(OH)₆ with the nitrogenous base adenine. The adduct of infinite stacks of adenine molecules, Te(OH)₆ and water not only proves that Te(OH)₆ mimicks the role of water in the related hydrate adenine · 3 H₂O but also shows that the inclusion of Te(OH)₆ raises the number of HO–H and N–HO contacts and therefore increases the distance between the adenine rings to 3.31 Å in 1 in comparison to that in adenine trihydrate (3.22 Å). Additionally, the disodium ditellurate(VI) aggregate {[Te₂(O)₂(OH)₆(ONa)₂]₂ [NaOH · 12.5 H₂O]} ( 2 ) resulted from the reaction of 1 with 2 molar equivalents of aqueous NaOH. Dinuclear 2 represents the first X‐ray diffraction characterized example of a sodium tellurate(VI) constructed from [Te₂O₄(OH)₆]^2– dianions.     

(Ph4P)2[Be3(μ‐OH)3(H2O)6]Cl5: Kristallstruktur und DFT‐Rechnungen

Bis(tetraphenylphosphonium)‐tris(μ‐hydroxo)hexaaquatriberylliumpentachloride, (Ph₄P)₂[Be₃(μ‐OH)₃(H₂O)₆]Cl₅ ( 1 ), was surprisingly obtained by reaction of (Ph₄P)N₃ · n H₂O with BeCl₂ in dichloromethane suspension and subsequent crystallization from acetonitrile to give single crystals of composition 1· 5.25CH₃CN. According to the crystal structure determination space group P , Z = 2, lattice dimensions at 100 K: a = 1354.8(2), b = 1708.7(2), c = 1753.2(2) pm, α = 114.28(1)°, β = 94.80(1)°, γ = 104.51(1)°, R₁ = 0.0586] the [Be₃(μ‐OH)₃(H₂O)₆]³⁺ cations form six‐mem‐bered Be₃O₃ rings with boat conformation and distorted tetrahedrally coordinated beryllium atoms with the terminally coordinated H₂O molecules. The structure ist characterized by a complicated three dimensional hydrogen‐bridging network including O–H ··· O, O–H ··· Cl, and O–H ··· NCCH₃ contacts. DFT calculations result in nearly planar [Be₃(OH)₃] six‐membered ring conformations.     

Structural effects on the solid‐state photodimerization of 2‐pyridone derivatives in inclusion compounds

The structures of six crystalline inclusion compounds between various host molecules and three guest molecules based on the 2‐pyridone skeleton are described. The six compounds are 1,1′‐biphenyl‐2,2′‐dicarboxylic acid–2‐pyridone (1/2), C₁₄H₁₀O₄·2C₅H₅NO, (I–a), 1,1′‐biphenyl‐2,2′‐dicarboxylic acid–4‐methyl‐2‐pyridone (1/2), C₁₄H₁₀O₄·2C₆H₇NO, (I–c), 1,1′‐biphenyl‐2,2′‐dicarboxylic acid–6‐methyl‐2‐pyridone (1/2), C₁₄H₁₀O₄·2C₆H₇NO, (I–d), 1,1,6,6‐tetraphenyl‐2,4‐hexadiyne‐1,6‐diol–1‐methyl‐2‐pyridone (1/2), C₃₀H₂₂O₂·2C₆H₇NO, (II–b), 1,1,6,6‐tetraphenyl‐2,4‐hexadiyne‐1,6‐diol–4‐methy‐2‐pyridone (1/2), C₃₀H₂₂O₂·2C₆H₇NO, (II–c), and 4,4′,4′′‐(ethane‐1,1,1‐triyl)triphenol–6‐methyl‐2‐pyridone–water (1/3/1), C₂₀H₁₈O₃·3C₆H₇NO·H₂O, (III–d). In two of the compounds, (I–a) and (I–d), the host molecules lie about crystallographic twofold axes. In two other compounds, (II–b) and (II–c), the host molecules lie across inversion centers. In all cases, the guest molecules are hydrogen bonded to the host molecules through O—H...O=C hydrogen bonds [the range of O...O distances is 2.543 (2)–2.843 (2) Å. The pyridone moieties form dimers through N—H...O=C hydrogen bonds in five of the compounds [the range of N...O distances is 2.763 (2)–2.968 (2) Å]. In four compounds, (I–a), (I–c), (I–d) and (II–c), the molecules are arranged in extended zigzag chains formed via host–guest hydrogen bonding. In five of the compounds, the guest molecules are arranged in parallel pairs on top of each other, related by inversion centers. However, none of these compounds underwent photodimerization in the solid state upon irradiation. In one of the crystalline compounds, (III–d), the guest molecules are arranged in stacks with one disordered molecule. The unsuccessful dimerization is attributed to the large interatomic distances between the potentially reactive atoms [the range of distances is 4.027 (4)–4.865 (4) Å] and to the bad overlap, expressed by the lateral shift between the orbitals of these atoms [the range of the shifts from perfect overlap is 1.727 (4)–3.324 (4) Å]. The bad overlap and large distances between potentially photoreactive atoms are attributed to the hydrogen‐bonding schemes, because the interactions involved in hydrogen bonding are stronger than those in π–π interactions.     

Two 3d‐4f Heterometallic Coordination Polymers of Macrocyclic Oxamide with Benzotriazole‐5‐carboxylate Co‐ligand: Syntheses,Crystal Structures and Magnetic Properties

Two heterometallic 3d–4f coordination polymers, [Gd(CuL)₂(Hbtca)(btca)(H₂O)] · 2H₂O ( 1 ) and [Er(CuL)₂(Hbtca)(btca)(H₂O)] · H₂O · CH₃OH ( 2 ) (CuL, H₂L = 2,3‐dioxo‐5,6,14,15‐dibenzo‐1,4,8,12‐tetraazacyclo‐pentadeca‐7,13‐dien; H₂btca = benzotriazole‐5‐carboxylic acid) were synthesized by solvothermal methods and characterized by single‐crystal X‐ray diffraction. Complexes 1 and 2 exhibit a double‐strand meso‐helical chain structures formed by [Ln^IIICu^II₂] (Ln^III = Gd, Er) units by oxamide and benzotriazole‐5‐carboxylate bridges. They are isomorphic except that one free water molecule of 1 is replaced by a methanol molecule. All 1D chains are further interlinked by hydrogen bonds resulting in a 3D supramolecular architecture. The magnetic properties of the compound 1 and 2 are also discussed.     

Tris(1H‐benzimidazol‐2‐yl­meth­yl)­amine–solvent adducts

The tris­(1H‐benzimidazol‐2‐yl­meth­yl)­amine (ntb) mol­ecule crystallizes in different solvent systems, resulting in two kinds of adduct, namely the monohydrate, C₂₄H₂₁N₇·H₂O or ntb·H₂O, (I), and the acetonitrile–methanol–water (1/0.5/1.5) solvate, C₂₄H₂₁N₇·C₂H₃N·0.5CH₄O·1.5H₂O or ntb·1.5H₂O·0.5MeOH·MeCN, (II). In both cases, ntb adopts a tripodal mode to form hydrogen bonds with a solvent water mol­ecule via two N—H⋯O and one O—H⋯N hydrogen bond. In (I), the ntb·H₂O adduct is further assembled into a two‐dimensional network by N—H⋯N and O—H⋯N hydrogen bonds, while in (II), a double‐stranded one‐dimensional chain structure is assembled via N—H⋯O and O—H⋯O hydrogen bonds, with the acetonitrile mol­ecules located inside the cavities of the chain structure.     

Zu den Kristallstrukturen der Übergangsmetall(II)‐Dodekahydro‐closo‐Dodekaborat‐Hydrate Cu(H2O)5,5[B12H12]·2,5 H2O und Zn(H2O)6[B12H12]·6 H2O

On the Crystal Structures of the Transition‐Metal(II) Dodecahydro‐closo‐Dodecaborate Hydrates Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O and Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O By neutralization of an aqueous solution of the free acid (H₃O)₂[B₁₂H₁₂] with basic copper(II) carbonate or zinc carbonate, blue lath‐shaped single crystals of the octahydrate Cu[B₁₂H₁₂]·8 H₂O (≡ Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O) and colourless face‐rich single crystals of the dodecahydrate Zn[B₁₂H₁₂]·12 H₂O (≡ Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O) could be isolated after isothermic evaporation. Copper(II) dodecahydro‐closo‐dodecaborate octahydrate crystallizes at room temperature in the monoclinic system with the non‐centrosymmetric space group Pm (Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O: a = 768.23(5), b = 1434.48(9), c = 777.31(5) pm, β = 90.894(6)°; Z = 2), whereas zinc dodecahydro‐closo‐dodecaborate dodecahydrate crystallizes cubic in the likewise non‐centrosymmetric space group F23 (Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O: a = 1637.43(9) pm; Z = 8). The crystal structure of Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O can be described as a monoclinic distortion variant of the CsCl‐type arrangement. As characteristic feature the formation of isolated [Cu₂(H₂O)₁₁]⁴⁺ units as a condensate of two corner‐linked Jahn‐Teller distorted [Cu(H₂O)₆]²⁺ octahedra via an oxygen atom of crystal water can be considered. Since “zeolitic” water of hydratation is also present, obviously both classical H–O^δ?···^+δH–O and non‐classical B–H^δ?···^+δH–O hydrogen bonds play a significant role for the stabilization of the structure. A direct coordinative influence of the quasi‐icosahedral [B₁₂H₁₂]^2? anions on the Cu²⁺ cations has not been determined. The zinc compound Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O crystallizes in a NaTl‐type related structure. Two crystallographically different [Zn(H₂O)₆]²⁺ octahedra are present, which only differ in their relative orientation within the packing of the [B₁₂H₁₂]^2? anions. The stabilization of the crystal structure takes place mainly via H–O^δ?···^+δH–O hydrogen bonds, since again the hydrogen atoms of the [B₁₂H₁₂]^2? anions have no direct coordinative influence on the Zn²⁺ cations.     

Interaction energy and the shift in OH stretch frequency on hydrogen bonding for the H2O → H2O,CH3OH → H2O,and H2O → CH3OH dimers

The ability to use calculated OH frequencies to assign experimentally observed peaks in hydrogen bonded systems hinges on the accuracy of the calculation. Here we test the ability of several commonly employed model chemistries—HF, MP2, and several density functionals paired with the 6‐31+G(d) and 6‐311++G(d,p) basis sets—to calculate the interaction energy (D_e) and shift in OH stretch fundamental frequency on dimerization (δ(ν)) for the H₂O → H₂O, CH₃OH → H₂O, and H₂O → CH₃OH dimers (where for X → Y, X is the hydrogen bond donor and Y the acceptor). We quantify the error in D_e and δ(ν) by comparison to experiment and high level calculation and, using a simple model, evaluate how error in D_e propagates to δ(ν). We find that B3LYP and MPWB1K perform best of the density functional methods studied, that their accuracy in calculating δ(ν) is ≈ 30–50 cm^?1 and that correcting for error in D_e does little to heighten agreement between the calculated and experimental δ(ν). Accuracy of calculated δ(ν) is also shown to vary as a function of hydrogen bond donor: while the PBE and TPSS functionals perform best in the calculation of δ(ν) for the CH₃OH → H₂O dimer their performance is relatively poor in describing H₂O → H₂O and H₂O → CH₃OH. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010     

Hydroxo‐bridged Tetranuclear CuII Complexes: {[Cu(bpy)(OH)]4Cl2}Cl2 · 6 H2O and {[Cu(phen)(OH)]4(H2O)2}]Cl4 · 4 H2O

The blue tetranuclear Cu^II complexes {[Cu(bpy)(OH)]₄Cl₂}Cl₂ · 6 H₂O ( 1 ) and {[Cu(phen)(OH)]₄(H₂O)₂}Cl₄ · 4 H₂O ( 2 ) were synthesized and characterized by single crystal X‐ray diffraction. ( 1 ): P 1 (no. 2), a = 9.240(1) Å, b = 10.366(2) Å, c = 12.973(2) Å, α = 85.76(1)°, β = 75.94(1)°, γ = 72.94(1)°, V = 1152.2(4) ų, Z = 1; ( 2 ): P 1 (no. 2), a = 9.770(3) Å, b = 10.118(3) Å, c = 14.258(4) Å, α = 83.72(2)°, β = 70.31(1)°, γ = 70.63(1)°, V = 1252.0(9) ų, Z = 1. The building units are centrosymmetric tetranuclear {[Cu(bpy)(OH)]₄Cl₂}²⁺ and {[Cu(phen)(OH)]₄(H₂O)₂}⁴⁺ complex cations formed by condensation of four elongated square pyramids CuN₂(OH)₂L^ap with the apical ligands L^ap = Cl, H₂O, OH. The resulting [Cu₄(μ₂‐OH)₂(μ₃‐OH)₂] core has the shape of a zigzag band of three Cu₂(OH)₂ squares. The cations exhibit intramolecular and intermolecular π‐π stacking interactions and the latter form 2D layers with the non‐bonded Cl^– anions and H₂O molecules in between (bond lengths: Cu–N = 1.995–2.038 Å; Cu–O = 1.927–1.982 Å; Cu–Cl^ap = 2.563; Cu–O^ap(OH) = 2.334–2.369 Å; Cu–O^ap(H₂O) = 2.256 Å). The Cu…Cu distances of about 2.93 Å do not indicate direct interactions, but the strongly reduced magnetic moment of about 2.74 B.M. corresponds with only two unpaired electrons per formula unit of 1 (1.37 B.M./Cu) and obviously results from intramolecular spin couplings (χ_m(T‐θ) = 0.933 cm³ · mol^–1 · K with θ = –0.7 K).     

Experimental Determination of the Isotherm at 15°C of the System Mg<Superscript>2+</Superscript>/Cl<Superscript>−</Superscript>, SO<Subscript>4</Subscript><Superscript>2</Superscript>–H<Subscript>2</Subscript>O

Summary.  The diagram of the ternary system Mg²⁺/Cl⁻, SO₄ ²⁻–H₂O was established at 15°C by means of analytical and conductimetric measurements. Three compounds were found in this diagram, which are MgSO₄·6H₂O, MgSO₄·7H₂O, and MgCl₂·6H₂O. The solubility field of MgSO₄·7H₂O is important whereas those of MgSO₄·6H₂O and MgCl₂·6H₂O are small. The compositions (mass-%) of the two invariant points determined by the two methods are: MgSO₄:MgCl₂=2.73:33.80 and MgSO₄: MgCl₂=3.38:28.91. Both the measured and the calculated isotherm at 15°C have been used for modelling of the diagram Mg²⁺/Cl⁻, SO₄ ²⁻–H₂O between 0 and 35°C. The polythermal invariant point was approximately located between 15 and 10°C.  Corresponding author. E-mail: ariguib@planet.tn Received October 16, 2002; accepted (revised) December 3, 2002 Published online April 24, 2003 RID="a" ID="a" Dedicated to Prof. Dr. Heinz Gamsj?ger on the occasion of his 70^th birthday     

Untersuchung von Hydrolysereaktionen zum Aufbau von Eisen(III)‐Oxo‐Aggregaten

Investigation of the Hydrolytic Build‐up of Iron(III)‐Oxo‐Aggregates The synthesis and structures of five new iron/hpdta complexes [{Fe^III₄(μ‐O)(μ‐OH)(hpdta)₂(H₂O)₄}₂Fe^II(H₂O)₄]·21H₂O ( 2 ), (pipH₂)₂[Fe₂(hpdta)₂]·8H₂O ( 4 ), (NH₄)₄[Fe₆(μ‐O)(μ‐OH)₅(hpdta)₃]·20.5H₂O ( 5 ), (pipH₂)_1.5[Fe₄(μ‐O)(μ‐OH)₃(hpdta)₂]·6H₂O ( 7 ), [{Fe₆(μ₃‐O)₂(μ‐OH)₂(hpdta)₂(H₄hpdta)₂}₂]·py·50H₂O ( 9 ) are described and the formation of these is discussed in the context of other previously published hpdta‐complexes (H₅hpdta = 2‐Hydroxypropane‐1, 3‐diamine‐N, N, N′, N′‐tetraacetic acid). Terminal water ligands are important for the successive build‐up of higher nuclearity oxy/hydroxy bridged aggregates as well as for the activation of substrates such as DMA and CO₂. The formation of the compounds under hydrolytic conditions formally results from condensation reactions. The magnetic behaviour can be quantified analogously up to the hexanuclear aggregate 5 . The iron(III) atoms in 1 ‐ 7 are antiferromagnetically coupled giving rise to S = 0 spin ground states. In the dodecanuclear iron(III) aggregate 9 we observe the encapsulation of inorganic ionic fragments by dimeric{M₂hpdta}‐units as we recently reported for Al^III/hpdta‐system.