Layered structure of a supramolecular hybrid sulfate salts: thermal stability and magnetic behavior

International audienceThe incorporation of the aromatic diamine 2-methylimidazole as template in the synthesis of hybrid sulfate salts with transition metal was effected by the slow evaporation method. The resulting structure presents a lamellar character with a supramolecular network, which is uncommon in the family of sulfates and their derivates. The three synthesized compound with the general formula (C4H7N2)2[MII(H2O)6](SO4)2·2H2O (MII = Zn, Co and Mn) crystallize in the monoclinic symmetry, space group P21/c. According to the design shape of the protonated amine and its bonding relations between the supramolecular inorganic layers, building from hydrogen bond only, the interlamellar distance reached 11.6 Å. The π-stacking between aromatic moieties of amines have a relevant role in stabilizing the lamellar structure. The thermal study with in situ powder X-ray diffraction and thermogravimetry of the synthesized compounds showed that the dehydration stage of precursors lead to the formation of an anhydrous crystalline phase with a good thermal stability. Beyond this and under the decomposition stage, Co and Zn compound become amorphous whereas the Mn-based compound showed successive crystalline phases. The magnetic measurements performed for the cobalt based compound indicate a low interaction exchange within the material in agreement with a typical paramagnetic behavio

Ethyl­enediammonium tetraaquadi­sulfatomagnesium(II)

The title compound, [NH3(CH2)2NH3][Mg(SO4)2(H2O)4], was synthesized by the slow evaporation method. Its crystal structure can be described as an alternate stacking of inorganic layers of tetra­aqua­bis(sulfato-O)magnesium [Mg(SO4)2(H2O)4]2− anions ( symmetry) and organic layers of [NH3(CH2)2NH3]2+ cations along the crystallographic b axis. The anions, built up from tetrahedral SO4 units and octahedral Mg(H2O)4O2 units, and the cations are linked together through N—H⋯O hydrogen bonds, forming a three-dimensional network. O—H⋯O inter­actions are also present

Crystal structures and characterization of two divalent metal selenates templated by dabco, (C6H14N2)[MII(H2O)6](SeO4)2 (MII: NiII, ZnII)

International audienceTwo new organic-inorganic hybrid materials have been synthesized and crystallographically characterized. Both compounds, (C6H14N2)[Ni(H2O)6](SeO4)2 (I) and (C6H14N2)[Zn(H2O)6](SeO4)2 (II), crystallize isotypically in the monoclinic system, space group P21/c, with the following unit cell parameters: a = 12.4045(3), b = 11.9360(3), c = 12.8366(3) Å, β = 108.518(2)°, V = 1802.18(8) Å3, Z = 4 for compound (I) and a = 12.7839(2), b = 11.9153(4), c = 12.3814(2) Å, β = 108.264(5)°, V = 1790.97(7) Å3, Z = 4 for the zinc related phase. Their supramolecular structure consists of metallic cation octahedrally coordinated by six water molecules [MII(H2O)6]2+, selenate anions (SeO4)2- and dabcodiium cation (C6H14N2)2+ linked together via two types of hydrogen bonds, Ow-H...O and N-H...O only. The thermal decomposition of these supramolecular compounds takes place in several steps leading to the formation of metal oxide. The magnetic measurements show that the nickel based compound is predominantly paramagnetic with weak antiferromagnetic interactions at low temperature

Inorganic-organic hybrid double sulfates as catalysts of the diastereoselective nitroaldol reaction

International audienceBis(1-phenylethanaminium) disulfatotetraaquazincate(II) dihydrate (C8H12N)2[Zn(H2O)4(SO4)2]*2H2O (1), bis(1H-benzo[d]imidazolium) hexaaquazinc(II) bis(sulfate) tetrahydrate (C7H7N2)2[Zn(H2O)6](SO4)2*4H2O (2) and bis(2-methyl-1H-imidazolium) hexaaquazinc(II) bis(sulfate) dihydrate (C4H7N2)2[Zn(H2O)6](SO4)2*2H2O (3) have been synthesized and fully structurally characterized including single-crystal X-ray diffraction analysis. 1-3 are organically templated hybrid layered materials comprising aquazinc(II) and aminium cations and sulfate anions. 1-3 are effective catalysts in the asymmetric Henry reaction; 1 being the most efficient one (yields up to 85% and threo/erythro diastereoselectivity up to 89:11)

Synthesis, characterization and magnetic properties of four new organically templated metal sulfates [C5H14N2][M(II)(H2O)6](SO4)2, (M(II) = Mn, Fe, Co, Ni).

International audienceA series of novel organically templated metal sulfates, [C(5)H(14)N(2)][M(II)(H(2)O)(6)](SO(4))(2) with (M(II) = Mn (1), Fe (2), Co (3) and Ni (4)), have been successfully synthesized by slow evaporation and characterized by single-crystal X-ray diffraction as well as with infrared spectroscopy, thermogravimetric analysis and magnetic measurements. All compounds were prepared using a racemic source of the 2-methylpiperazine and they crystallized in the monoclinic systems, P2(1)/n for (1, 3) and P2(1)/c for (2,4). Crystal data are as follows: [C(5)H(14)N(2)][Mn(H(2)O)(6)](SO(4))(2), a = 6.6385(10) Å, b = 11.0448(2) Å, c = 12.6418(2) Å, β = 101.903(10)°, V = 906.98(3) Å(3), Z = 2; [C(5)H(14)N(2)][Fe(H(2)O)(6)](SO(4))(2), a = 10.9273(2) Å, b = 7.8620(10) Å, c = 11.7845(3) Å, β = 116.733(10)°, V = 904.20(3) Å(3), Z = 2; [C(5)H(14)N(2)][Co(H(2)O)(6)](SO(4))(2), a = 6.5710(2) Å, b = 10.9078(3) Å, c = 12.5518(3) Å, β = 101.547(2)°, V = 881.44(4) Å(3), Z = 2; [C(5)H(14)N(2)][Ni(H(2)O)(6)](SO(4))(2), a = 10.8328(2) Å, b = 7.8443(10) Å, c = 11.6790(2) Å, β = 116.826(10)°, V = 885.63(2) Å(3), Z = 2. The three-dimensional structure networks for these compounds consist of isolated [M(II)(H(2)O)(6)](2+) and [C(5)H(14)N(2)](2+) cations and (SO(4))(2-) anions linked by hydrogen-bonds only. The use of racemic 2-methylpiperazine results in crystallographic disorder of the amines and creation of inversion centers. The magnetic measurements indicate that the Mn complex (1) is paramagnetic, while compounds 2, 3 and 4, (M(II) = Fe, Co, Ni respectively) exhibit single ion anisotropy

Ethyl­enediammonium tetra­aqua­disulfato­cadmate

The crystal structure of the title compound, [NH3(CH2)2NH3][Cd(SO4)2(H2O)4], consists of [Cd(SO4)2(H2O)4]2− anions that are built from octa­hedral Cd(H2O)4O2 and SO4 tetra­hedral units linked by corner sharing. The ethyl­ene­diamminium cations are linked to the anions via N—H⋯O hydrogen bonds. The asymmetric unit contains one-half of the compound, the other half being related to the first by an inversion centre. The crystal structure presents alternate stacking of the inorganic and organic layers along the crystallographic b axis. The structure cohesion and stability is further assured by O(water)—H⋯O hydrogen bonds

A supramolecular double sulfate salt with a lamellar type: crystal structures and thermal behavior

The synthesis of a series of supramolecular double sulfate salts using transition metals and the aromatic amine -methylbenzylamine afforded an unexpected hybrid lamellar structure type. (C8H12N)2[M(H2O)4(SO4)2].2H2O (M = Fe to Zn) crystallizes with a monoclinic structure (S.G. P21/n), with a significant interlamellar distance of more than 16 Å. While comparable to common clay materials, the crystal structure is actually supramolecular, in particular the mineral layer is built from hydrogen bonds only. The interlayer space is filled with aromatic amines that form chains through C-H***π interactions. The thermal study of all metal compounds has revealed a good stability of the filled compounds up to 200°C. The dehydration proceeds differently according to the metal incorporated into the structure. In particular, the stepped release of water modifies drastically the interlayer space, which is able to vary from 14.8 to 18.8 Å, in opposite way for the Zn-related compound compared to other metals

Nouveaux molybdo-sulfates et molybdo-phosphates de type LAMOX (études structurales et vibrationnelles en relation avec la conduction anionique)

Le travail s inscrit dans le cadre général de l étude de la famille LAMOX, dont le prototype est La2Mo2O9, de structure monoclinique à température ambiante (phase ?), et qui présentent au dessus de 580C une phase cubique (?) ayant une conduction anionique supérieure à la meilleure zircone stabilisée actuellement utilisé comme électrolyte de pile SOFC (Solid Oxid Fuel Cell), et ce à températures plus basses. L'analogie structurale de la forme ?-La2Mo2O9 avec le composé ?-SnWO4 a permis de proposer une explication à l origine structurale de la conduction dans le molybdate de lanthane. Le remplacement de l étain divalent par le lanthane trivalent impliqueun apport d oxygène et la création de lacunes, qui viennent se substituer à la place de la paire libre E (5s2) de l étain (Sn2W2O8E2 ? La2Mo2O8+1?). La migration de cet oxygène supplémentaire par la lacune créée engendre l apparition d une conduction anionique.Le travail de thèse comporte deux volets :- recherche de nouvelles compositions pouvant présenter la phase conductrice ? à plus basses températures par substitution du molybdène par du soufre et du phosphore, systèmes n ayant pas jusqu alors fait l objet d investigations avancées ;- étude des propriétés vibrationnelles et dynamiques de ce type structural afin de comprendre le mécanisme de conduction anionique, et notamment l existence des changements de régimes de conduction observés en fonction de la température.Des phases pures La2Mo2-ySyO9 et La2Mo2-yPyO9-y/2 ont pu être élaborées jusqu à des teneurs en soufre de 30% (y=0.6) et de phosphore de 2.5% (y=0.05). La forme ? recherchée est stabilisée à la température ambiante pour des taux de soufre supérieurs à 5% et de phosphore supérieurs à 1,5%. Des analyses thermogravimétriques ont révélé que la substitution du molybdène par le soufre diminuait fortement la stabilité thermique des phases rendant ainsi leurs caractérisations par diffraction des rayons X et spectroscopie d impédance délicates. Pour la série La2Mo2-yPyO9-y/2, une ségrégation partielle du phosphore a été mise en évidence par spectroscopie RMN. Les mesures électriques réalisées sur les deux séries d échantillons ont montré une conductivité significative, mais néanmoins moindre que celle observée à haute température pour le composé parent La2Mo2O9.Le second volet visant à comprendre le mécanisme de conduction repose sur l étude des propriétés vibrationnelles. Il s est appuyé sur des études expérimentales par spectrométrie Raman en liaison avec des calculs ab-initio des spectres de phonons. Malgré des raies Raman très larges en raison du désordre structural, il a été possible de mettre en lumière des signatures caractéristiques des différentes phases en lien avec le réarrangement structural. L interprétation des spectres a été effectuée en s appuyant sur la parenté structurale avec le composé modèle ordonné ?-SnWO4. Ce système a permis de démontrer un haut degré de fiabilité des calculs ab-initio sur la base de comparaisons à des études expérimentales par Raman polarisé. Ces calculs transposés au cas du sous-réseau ordonné de LaMoO4 ont amenés à une attribution des signaux Raman. Ceci a permis d une part de démontrer que des structures observées sur des bandes vibrationnelles Raman devaient être attribuées à l existence de différents environnements atomiques, et d autre part l existence de singularités dans les spectres de phonons, lesquelles soutiennent le modèle préalablement proposé de conduction anionique assistée par phonons.A new ionic conductor of the solid solutions La2Mo2-yPyO9-y/2 (y ? 0.05) and La2Mo2-ySyO9 (y ? 0.6) has been prepared with conventional solid-state reaction method. The resultant oxide powders were characterized by X-ray diffraction. These two series of lanthanum molybdates, which belong to the LAMOX family of fast oxide-ion conductors, exhibits a different structural behavior depending on the substituting element. The effect of substituting P for Mo reveals that the phase transition which occurs in La2Mo2O9 around 560C disappears when y > 0.02. Substituting P in some degree (y > 0.02) for Mo6+ can suppress the phase transition and stabilizing the cubic phase of ?- La2Mo2O9. The sulfur series (up to around 30 %) suppress the phase transition which occurs in La2Mo2O9 around 580C from a low temperature ? form to a high temperature ?, and stabilize the ? form at room temperature.Thermogravimetric analysis showed that the substitution of molybdenum by sulfur greatly decreased the thermal stability of phases making their characterization by X-ray diffraction and impedance spectroscopy difficult. For the series La2Mo2-yPyO9-y/2, a partial segregation of phosphorus was demonstrated by NMR spectroscopy. Electrical measurements performed on the two sets of samples showed significant conductivity, but still less than that observed at high temperature for the parent compound La2Mo2O9.The infrared and Raman spectra of the low- and high-temperature phases of LAMOX were performed at ambient temperature. All theoretically predicted vibrations have been observed, and assignments have been given for the internal vibrations of the MoO42-, SO42- and PO43- ions as for the external vibrations. It is interesting to study the vibrational spectra of these two phases (? and ?) in order to obtain more conclusive data regarding the internal vibrations of the XO4 (X= Mo, P, S).LE MANS-BU Sciences (721812109) / SudocSudocFranceF

1-Methyl­piperazine-1,4-diium tetra­chloridozincate hemihydrate

The crystal structure of the title compound, (C5H14N2)[ZnCl4]·0.5H2O, is built up from discrete 1-methyl­piperazine­diium cations with chair conformation, tetrahedral tetrachloridozincate anions and uncoordinated solvent water mol­ecules linked together by three types of inter­molecular hydrogen bonds, viz. N—H⋯Cl, N—H⋯O and O—H⋯Cl

Hydrothermal synthesis of (C5H14N2)[CoCl4]⸳0.5H2O: Crystal structure, spectroscopic characterization, thermal behavior, magnetic properties and biological evaluation

The organic-inorganic compound (C5H14N2)[CoCl4]⸳0.5H2O, I, was characterized by various physicochemical techniques. The X-ray diffraction analysis revealed that the compound crystallizes in the centrosymmetric space group C2/c of the monoclinic system. The atomic arrangement the Co(II) complex is built from isolated [CoCl4]2– anions, 1-methylpiperazine-1,4-diium [C5H14N2]2+ cations and free water molecules. The crystal structure study showed that the cohesion of I is assured through N–H···Cl and N–H···O hydrogen bonds giving birth to a 3-D architecture. Hirshfeld surface analysis revealed that Cl···H/H···Cl and H···H (58.5 and 36.4%, respectively) are the most significant interactions between species. Minor O···H/H···O interactions are also present. The compound was characterized by thermal analysis, TGA-DTA showed the removal of the co-crystallized water before 100 °C and a first mass loss at around 120 °C. Magnetic measurements are in good agreement with isolated, S = 3/2, tetrahedral [CoCl4]2− anions. The negative Weiss constant of -1.35 indicates single-ion anisotropy and very weak antiferromagnetic interactions. UV–visible spectroscopy reveals three weak absorption bands in the visible range due to the d-d electronic transitions typical of the Co(II) tetra-coordinated. A bioassay showed antibacterial activity against the gram negative Klebsiella pneumonia and gram positive Bacillus ceureus, Listeria monocytogenes, and Micrococcus lutues