A novel (3,4,8)-connected 3D topology framework based on [Gd2(bpdc)3(H2O)3] second building units

A new 3D coordination polymer {[Gd₂(bpdc)₃(H₂O)₃]·H₂O}_n(1) has been isolated from the reaction of 2,2′-bipyridine-4,4′-dicarboxylic acid (H₂bpdc) and Gd(III) salts under hydrothermal conditions. Single-crystal X-ray diffraction study shows that compound 1 is constructed from Gd₂-based second building units (SBUs) [Gd₂(bpdc)₃(H₂O)₃] and displays a 3D (3,4,8)-connected net with (4²·6)(3²·4²·5²)(3²·4⁵·5⁴·6¹¹·7⁶) topology. A thermogravimetric analysis of 1 shows a high thermal stability. The magnetic behavior of 1 reveals a weak antiferromagnetic interaction between Gd(III) ions.     

Synthesis and crystal structure of Zn[O3PCH(NH2)CH3] · 2H2O, the first zinc α-aminoethylphosphonate with a layer structure

A novel tetrahedrally coordinated zinc phosphonate, Zn[O₃PCH(NH₂)CH₃] · 2H₂O, has been synthesized using hydrothermal techniques. X-ray diffraction indicates that this material is a two-dimensional layered structure with the organic part of the phosphonate anion being directed into the interlayer region. The zinc atoms are coordinated by three oxygens of three different phosphonate groups, and by the nitrogen of an additional phosphonate unit.     

Synthesis and structural characterization of an alternating double aquo-bridged and single cyano-bridged polymeric barium–iron complex: {[Ba2(phen)4(H2O)6Fe(CN)6]·Cl·2(phen)·3H2O}n

A new alternating double aquo-bridged and single cyano-bridged polymeric complex {[Ba₂(phen)₄(H₂O)₆Fe(CN)₆]·Cl·2(phen)·3H₂O}_n (1) (phen = 1,10-phenanthroline) has been synthesized and structurally characterized. In the crystal structure the two centrosymmetric [Ba₂(phen)₄(H₂O)₆] units are bridged through two trans CN groups of [Fe(CN)₆]³⁻ ion, which results in the formation of a zig-zag polymeric chain. In each [Ba₂(phen)₄(H₂O)₆] unit, the two Ba centers are joined by double aquo bridges. Both the Ba atoms are 9-coordinated with distorted mono-capped square antiprismatic geometry. An elaborate hydrogen bonding system holds the parallel polymeric chains together.     

Synthesis and crystal structure of carbonate cancrinite Na8[AlSiO4]6CO3(H2O)3.4, grown under low-temperature hydrothermal conditions

The synthesis of cancrinite in the system Na₂O–SiO₂–Al₂O₃–Na₂CO₃–H₂O was studied under low-temperature hydrothermal conditions in the 353 K<T<473 K interval. The aim was to reveal the suitable range for the crystallization of pure-phase carbonate cancrinite with the ideal composition Na₈[AlSiO₄]₆CO₃(H₂O)₂ without cocrystallization of sodalite or intermediate disordered phases between cancrinite and sodalite. It was found that cancrinite formation reacts very sensitive on the temperature within the autoclaves whereas the concentration of reactants and the alkalinity of the hydrothermal solution have a much lower influence on the phase formation. Thus the temperature of crystallization of carbonate cancrinite without any by-products should not remain below 473 K. At the lower reaction temperature of 353 K the formation of a disordered intermediate phase between the cancrinite and the sodalite structure has been obtained in every case, independent of the template concentrations and the base. Some problems to detect this in a typical powder product mixture are discussed. Besides the ²⁹Si and ²⁷Al MAS NMR characterization of the products, the crystal structure refinement of pure carbonate cancrinite of ideal composition Na₈[AlSiO₄]₆CO₃(H₂O)_3.4, has been carried out from X-ray powder data using the Rietveld method: P6₃, a=1271.3(1) pm, c=518.6(1) pm, R_WP=0.073, R_F=0.016 for 347 structure factors and 45 variable positional parameters.     

A hemidirected 1-D coordination polymer [Pb2(H2O)2(HBTC)2] · 3H2O extended in holodirected 3-D by weak Pb–O interactions

A new complex, [Pb₂(H₂O)₂(HBTC)₂] · 3H₂O (H₃BTC = 1,3,5-Benzenetricarboxylic acid) (1), has been synthesized under hydrothermal condition. The single-crystal analysis shows that 1 consists of 1-D double-chains with Pb(II) six-coordinated by three H₃BTC and one H₂O molecule with the Pb–O bond distances in the range of 2.56–2.76 Å. When the Pb–O bonding limit extends from 2.76 to 2.90 Å, the potential weak bonds of Pb–O can be found and the coordination number of Pb will increase from six to nine. As a result, the coordination geometry of Pb(II) transforms from hemidirected to holodirected and an infinite 3-D framework is obtained by the connection of the double-chains. The IR spectrum and the TGA–DTA curve of 1 are also reported in this paper.     

Structural phase transition and high temperature phase structure of Friedels salt, 3CaO · Al2O3 · CaCl2 · 10H2O

Friedels salt, the chlorinated compound 3CaO · Al₂O₃ · CaCl₂ · 10H₂O (AFm phase), presents a structural phase transition at about 30°C from a monoclinic to a rhombohedral phase. It has been studied by X-ray powder diffraction and optical microscopy in transmitted light with crossed polarisers on single crystals prepared by hydrothermal synthesis. The high temperature phase was determined at 37°C from X-ray single crystal diffraction data. The compound crystallises in the space group R c with lattice parameters of a = 5.7358(6)Å and c = 46.849(9)Å (Z = 3 and D_x = 2.111 g/cm³). The refinement of 498 independent reflections with I > 2σ(I) led to a residual factor of 7.1%. The Friedels salt can be described as a layered structure with positively charged main layers of composition [Ca₂Al(OH)₆]⁺ and negatively charged layers of composition [Cl⁻,2H₂O]. The chloride anions are surrounded by 10 hydrogen atoms, of which six belong to hydroxyl groups and four to water molecules. The structural phase transition may be related to the size of the chloride anions, which are not adapted to the octahedral cavity formed by bonded water molecules.     

[H3NNH3]2K2MnMo9O32·(NH3)·3H2O: synthesis and crystal structure determination of a novel heteropolyoxometallate related to the Waugh structure

A novel heteropolyoxometallate with the formula [H₃NNH₃]₂K₂MnMo₉O₃₂·(NH₃)·3H₂O has been prepared in water solution. The crystal structure of the title compound was determined by the single-crystal method. This new mixed metal anionic complex crystallizes in the rhombohedral space group R3 (No. 146) with a=b=15.873(5), c=12.344(6) Å, γ=120°. The disordered structure contains three molecules in the unit cell. Full-matrix least-squares refinements of the title complex yielded final reliability (R) factors of 0.0356 (Rw=0.0868) with a goodness-of-fit (GOF, Σ₂) value of 1.099 based on 1430 [I>2σ(I)] observed reflections. All Mo and Mn atoms are six-coordinated octahedrally to form a Mn-centered cage with a Mo₉O₃₂ group as the framework.     

A porous mixed-valent iron MOF exhibiting the acs net: Synthesis, characterization and sorption behavior of Fe3O(F4BDC)3(H2O)3·(DMF)3.5

A new mixed-valent iron MOF, formulated as Fe₃O(F₄BDC)₃(H₂O)₃·(DMF)_3.5 (1), has been synthesized by using a perfluorinated linear dicarboxylate to link trigonal prismatic Fe₃(μ³-O)(O₂C–)₆ clusters. The structure refinement based on single crystal X-ray diffraction data collected from 1 reveals the material exhibits the acs topology with large channels along the crystallographic c-axis. Due to the presence of fluorine atoms the organic link, 2,3,5,6-tetrafluorobenzene-1,4-dicarboxylate (F₄BDC), has a 63° torsion angle between the carboxylate and aromatic planes, resulting in larger channels compared to those in the isoreticular material MOF-235. While few iron-based MOFs have demonstrated porosity, nitrogen and hydrogen sorption experiments carried out at 77 K proved the porosity of outgassed 1, which has a Langmuir surface are of 635 m²/g and a gravimetric capacity of 0.9 wt% of hydrogen at 1 bar.     

Synthesis, characterization and crystal structure of a novel co-ordination polymer [Co(BTB)2(NCS)2]n

A novel polymeric cobalt(II) complex with flexible ligand, [Co(BTB)₂(NCS)₂]_n 1 {BTB = 1,4-bis(1,2,4-triazol-1-yl)butane} has been prepared and structurally characterized by single-crystal X-ray diffraction as well as with elemental analysis, infrared spectroscopy and thermogravimetric analysis. The complex 1 consists of two discrete constituents, A and B, with the same chemical formula [Co(BTB)₂(NCS)₂] but different connecting mode. The six-co-ordination of Co²⁺ in A and B is in a distorted octahedral environment formed by four nitrogen atoms of the triazoles and two nitrogen atoms from two trans thiocyanato ligands. The structures of A and B demonstrate a one-dimensional neutral looped chain through two BTB-bridges and a two-dimensional network in which four BTB bridge four Co(II) atoms, respectively. A and B interpenetrate in an inclined fashion. The flexible BTB ligand exhibits three different configurations in 1.     

Synthesis, crystal structure and thermal stability of tetrahydroborate sodalite Na8[AlSiO4]6(BH4)2

Tetrahydroborate sodalite formation was investigated in the system Na₂O–SiO₂–Al₂O₃–NaBH₄–H₂O under mild hydrothermal conditions. Due to the high degree of decomposition of hydroborates in aqueous solutions synthesis conditions were tuned by variation of the parameters alkalinity, liquid/solid ratio, reaction temperature and reaction time. The insertion of 8–16 molar NaOH solution was crucial for the higher stability of pure tetrahydroborate salt under strong alkaline conditions. Synthesis at 393 K and 24 h reaction time reveal tetrahydroborate sodalite Na₈[AlSiO₄]₆(BH₄)₂ beside a small amount of amorphous material within the total batch. Structure, composition and thermal stability of this new sodalite was investigated using XRD, NMR, infrared and TG/DTA methods. The crystal structure of tetrahydroborate sodalite has been refined in the space group P-43n with a = 891.61(2) pm. The Si- and Al-atoms of the aluminosilicate framework are completely ordered. The boron atoms of the tetrahydroborate anions are located at the centre of the sodalite cage whereas the hydrogen atoms are positionally disordered. Na₈[AlSiO₄]₆(BH₄)₂ shows a high stability under inert gas conditions. At atmospheric conditions the group can be oxidized to borate and boroxide anions suggesting the formation of hydrogen which leaves the sodalite cages. Future investigation of reloading properties of the oxidized form could be highly interesting for the hydrogen storage capabilities of these sodalites.     

Ferromagnetic coupling in a novel dicyanamide-bridged dinuclear gadolinium(III) complex [Gd2(dca)4(OH)2 (NITpPy)4] (NITpPy = 4-pyridyl-nitronyl nitroxide radical)

The novel six-coordinated gadolinium(III) complex of formula [Gd₂(dca)₄(OH)₂(NITpPy)₄] (1) (dca = dicyanamide, NITpPy = 4-pyridyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-oxy-3-oxide) has been prepared and characterized by X-ray crystallography. Compound 1 is a dimer structure made up of double μ_1,5-dca-bridged gadolinium(III) ions and one terminal dca ligand; variable-temperature magnetic susceptibility measurements reveal the occurrence of a significant ferromagnetic interaction directly spin polarization through the NITpPy–Gd(III)–NITpPy pathway with J = 11.56 cm⁻¹.     

A novel Keggin-type tungstogermanate dimer bearing dinuclear copper-organic coordination ions: {H8[Cu(phen)(μ2-CH3COO)2Cu(phen)(H2O)]2[Ge2W23CuO80]} · 24H2O

An unprecedented Keggin-type tungstogermanate dimer bearing dinuclear copper-organic coordination ions {H₈[Cu(phen)(μ₂-CH₃COO)₂Cu(phen)(H₂O)]₂[Ge₂W₂₃CuO₈₀]} · 24H₂O has been synthesized and characterized by IR, UV, ICP analyses, ESR spectra, element analysis, TG and single crystal X-ray diffraction analysis. The compound is built up from a dimeric heteropolyanion constituted by two corner-shared Keggin-type building subunits and two dinuclear copper-organic coordination cations [Cu(phen)(μ₂-CH₃COO)₂Cu(phen)(H₂O)]²⁺, each of which consists two square pyramidal copper-phen ions bridged by two μ₂-acetate ligands.     

Direct growth of Cu3(BTC)2(H2O)3 · xH2O thin films on modified QCM-gold electrodes – Water sorption isotherms

The preparation of a thin film of the metal–organic framework Cu₃(BTC)₂(H₂O)₃ · xH₂O (HKUST-1) on the gold electrode of a quartz-crystal microbalance (QCM) was achieved by direct growth on a 11-mercaptoundecanol self-assembled monolayer (SAM). The formation of the SAM on the gold substrate was proven via reflection–absorption infrared-spectroscopy. The HKUST-1 thin film was characterized by X-ray diffraction, Raman-spectroscopy, and scanning-electron microscopy. Water vapor sorption measurements allow us to directly characterize the sorption properties of the thin film grown on the electrode of the QCM-device.     

Synthesis and structure of [{As(NBu)3}2Li6] containing an [As(NBu)3] trianion

Attempts to prepare the [As(N^tBu)₃]³⁻ trianion by the reaction of As(NMe₂)₃ with [^tBuNHLi]_n (1:3 monomer equiv.) proved unsuccessful. However, if the reaction is carried out with an excess of ^tBuNH₂ (3 equiv.) the target complex [{As(N^tBu)₃}₂Li₆] (1) is obtained. This is the first example of a complex containing an [As(NR)₃]³⁻ trianion.     

[SmNi(pic)3(H2O)5]n(ClO4)2n · 3nH2O, the first Sm–Ni heterometallic complex of picolinic acid ligand showing novel basket weave topology: Synthesis, structure and magnetics

The first basket weave framework topology of Sm–Ni heterometallic complex with picolinic acid as bridging ligand showing two different coordination modes of picolinic acid has been characterized; The studies on temperature-dependent magnetization indicate the title complex follows the Curie–Wiess paramagnetic behavior down to 5 K.     

The crystal structure of jennite, Ca9Si6O18(OH)6·8H2O

The crystal structure of jennite is solved and refined in the space group P1?, by using single crystal X-ray diffraction data collected at the Elettra synchrotron radiation facility on a very thin crystal from Fuka, Japan. The triclinic refined unit cell is a=10.576(2) Å, b=7.265(2) Å, c=10.931(3) Å, α=101.30(1), β=96.98(1), γ=109.65(1)°. The structure of jennite is built up by three distinct modules: ribbons of edge-sharing calcium octahedra, silicate chains of wollastonite-type running along b, and additional calcium octahedra on inversion centres. The structural results indicate that the crystal chemical formula of jennite is Ca₉Si₆O₁₈(OH)₆·8H₂O, and that all the hydroxyl groups are bonded to three calcium cations; SiOH groups are not found. The structural disorder observed in jennite is explained on the basis of the OD theory, and a model for the structure of metajennite, the dehydration product of jennite, is proposed.     

Synthesis and structure of the n = 4 member of the framework aluminium alkylenediphosphonate series Al2[O3PCnH2nPO3](H2O)2F2

We report here the solvothermal synthesis and crystal structure of the hybrid inorganic-organic framework material Al₂[O₃PC₄H₈PO₃](H₂O)₂F₂⋅2H₂O (monoclinic, 1P2₁/m, a = 4.961(2) ?, b = 11.930(5) ?, c = 10.727(5) ?, β = 93.972(6)^∘, Z = 2, R(F, F² > 2σ) = 0.094, R_w(F², all data) = 0.262), the third member of the Al₂[O₃PC_nH_2nPO₃](H₂O)₂F₂ framework series. The structure is formed from corrugated chains of corner-sharing AlO₄F₂ octahedra in which alternating AlO₄F₂ octahedra contain two fluorine atoms in a trans or a cis configuration. The diphosphonate groups link the chains together through Al-O-P-O-Al bridges and through the butyl groups to form a three-dimensional framework structure containing a one-dimensional channel system consisting of one type of channel only. The channels contain four extra-framework water molecules per unit cell. The formation of this member of the series shows that the form of the alkyl chain can successfully define the number of channel types and the channel length in this hybrid framework system.     

New ferrocene-derived hydroxymethylphosphines: FcP(CH2OH)2 [Fc=(η-C5H5)Fe(η-C5H4)] and the dppf analogue 1,1-Fc[P(CH2OH)2]2 [Fc=Fe(η-C5H4)2]

Reactions of the ferrocene-phosphines FcPH₂ and 1,1^′-Fc^′(PH₂)₂ with excess formaldehyde gives the new hydroxymethylphosphines FcP(CH₂OH)₂ 1 and 1,1^′-Fc^′[P(CH₂OH)₂]₂ 2, respectively. Phosphine 1 is an air-stable crystalline solid, whereas 2 is isolated as an oil. Reaction of 1 with H₂O₂, S₈ or Se gives the chalcogenide derivatives FcP(E)(CH₂OH)₂ (E=O, S or Se), whilst reaction of 2 with S₈ gives 1,1^′-Fc^′[P(S)(CH₂OH)₂]₂, which were fully characterised. Phosphine 1 was also characterised by an X-ray crystal structure determination.