139 research outputs found
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
A second monoclinic polymorph of ethylenediammonium bis(hydrogen squarate) monohydrate
The title compound, C2H10N2
2+·2HC4O4
−·H2O, a new polymorph of ethylenediammonium bis(hydrogen squarate) monohydrate, was synthesized by slow evaporation of an acid solution. The asymetric unit contains two hydrogen squarate anions, two half-molecules of protonated ethylenediamine arranged around a twofold axis and one water molecule. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds between the hydrogen squarate anions, protonated N atoms from the amine group and water molecules lead to a three-dimensional framework. In particular, the cohesion between the squarate groups is ensured by very short intermolecular hydrogen bonds bonds. The title compound crystallized together with the previously reported polymorph [Mathew et al. (2002 ▶). J. Mol. Struct.
641, 263–279]
catena-Poly[[{bis[tetraaqua(2-hydroxy-3,4-dioxocyclobut-1-en-1-olato-κO 1)bariumstrontium(0.35/0.65)]di-μ-aqua}bis(μ-2-hydroxy-4-oxocyclobut-1-ene-1,3-diolato-κ2 O 1:O 3)] monohydrate]
The title structure, {[Ba0.71Sr1.29(C4HO4)4(H2O)10]·H2O}n, is built from dimers of edge-sharing monocapped square antiprisms [(Ba/Sr)O3(H2O)6], in which barium and strontium are statistically disordered [ratio 0.353 (8):0.647 (8)] on the same crystallographic site. Such dimers are connected via bidentate hydrogen squarate groups [HC4O4]−, leading to chains that propagate along the b axis. Inter- and intramolecular O—H⋯O hydrogen bonds maintain the crystal packing through a three-dimensional network
Poly[[μ-aqua-tetraaquabis(μ-2-hydroxy-4-oxocyclobut-1-ene-1,3-diolato)strontium] hemihydrate]
In the title coordination polymer, {[Sr(C4HO4)2(H2O)5]·0.5H2O}n, the Sr2+ ion is coordinated by three monodentate hydrogensquarate (hsq) anions and six aqua ligands in a distorted SrO9 monocapped square-antiprismatic geometry. The hsq anions and water molecules bridge the metal ions into infinite sheets lying parallel to (100). The O atom of the uncoordinated water molecule lies on a crystallographic twofold axis. The packing is stabilized by numerous O—H⋯O hydrogen bonds
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
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
Yttrium ethylenediammonium squarate tetrahydrate
The title compound, {(C2H10N2)1.5[Y(C4O4)3(H2O)4]}n {systematic name: catena-poly[sesqui(ethylenediammonium) [[tetraaquabis(squarato-κO)yttrium(III)]-μ-squarato-κ2
O:O′]]}, was synthesized by slow evaporation of an acid solution. The asymetric unit contains one yttrium cation in an antiprismatic environnement, three squarate groups, one and a half protonated ethylenediamine molecules and four water molecules. YO8 polyhedra are connected through bis(monodentate) squarates, leading to infinite zigzag chains, in between which are located ammonium groups. A framework of hydrogen bonds between protonated amine N atoms, water molecules and squarate anions ensures the cohesion of the structure
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