scholarly journals Supramolecular Frameworks Based on Rhenium Clusters Using the Synthons Approach

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2662
Author(s):  
Nathalie Audebrand ◽  
Antoine Demont ◽  
Racha El Osta ◽  
Yuri V. Mironov ◽  
Nikolay G. Naumov ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Crystal Structures ◽  
Ligand Exchange ◽  
Alkaline Earth ◽  
Room Temperature ◽  
Hydration Rate ◽  
Rhenium Cluster ◽  
New Compounds ◽  
Cluster Unit

The reaction of the K4[{Re6Si8}(OH)a6]·8H2O rhenium cluster salt with pyrazine (Pz) in aqueous solutions of alkaline or alkaline earth salts at 4 °C or at room temperature leads to apical ligand exchange and to the formation of five new compounds: [trans-{Re6Si8}(Pz)a2(OH)a2(H2O)a2] (1), [cis-{Re6Si8}(Pz)a2(OH)a2(H2O)a2] (2), (NO3)[cis-{Re6Si8}(Pz)a2(OH)a(H2O)a3](Pz)·3H2O (3), [Mg(H2O)6]0.5[cis-{Re6Si8}(Pz)a2(OH)a3(H2O)a]·8.5H2O (4), and K[cis-{Re6Si8}(Pz)a2(OH)a3(H2O)a]·8H2O (5). Their crystal structures are built up from trans- or cis-[{Re6Si8}(Pz)a2(OH)a4−x(H2O)ax]x−2 cluster units. The cohesions of the 3D supramolecular frameworks are based on stacking and H bonding, as well as on H3O2−bridges in the cases of (1), (2), (4), and (5) compounds, while (3) is built from stacking and H bonding only. This evidences that the nature of the synthons governing the cluster unit assembly is dependent on the hydration rate of the unit.

scholarly journals Die Kristallstrukturen von Strontium- und Bariumhexacyanoferrat(III)-Hexamethylentetramin-Hydraten. Strukturmodell für Additionsverbindungen der Alkali- und Erdalkalimetallhexacyanoferrate mit Hexamethylentetramin / The Crystal Structures of Hydrates of Strontium and Barium Hexacyanoferrate(III) with Hexamethylenetetramine. Structural Model for Adducts of the Hexacyanoferrates of Alkaline and Alkaline Earth Metals with Hexamethylenetetramine

1989 ◽  
Vol 44 (5) ◽  
pp. 519-525 ◽  
Author(s):  
Hans-Jürgen Meyer ◽  
Joachim Pickardt
Keyword(s):  
Aqueous Solutions ◽  
Crystal Structures ◽  
General Formula ◽  
Alkaline Earth ◽  
Structural Model ◽  
Earth Metal ◽  
Alkaline Earth Metals ◽  
Alkaline Earth Metal ◽  
Monoclinic Space Group ◽  
Space Group

By reaction of methanolic solutions of hexamethylenetetramine with aqueous solutions of hexacyanoferrates(III) of strontium and barium resp., crystals of the compounds were obtained. Sr3[Fe(CN)6]2 · 3 C6H12N4 · 18 H2O, tetragonal, space group P42/nmc, Z = 4, a = 1931.8(4), c = 1579.9(4) pm, 1358 reflections. R = 0.066. Ba3[Fe(CN)6]2 · 2 C6H12N4 · 11 Η2Ο. monoclinic. space group P21/n, Ζ = 2, a = 1148.0(4), b = 1369.7(4), c = 1584.5(4) pm, γ = 95.79(3)°, 2583 reflections, R = 0.057. The crystal structures of these adducts are compared with those of other hexamethylenetetramine adducts of alkaline and alkaline earth metal hexacyanoferrates of the general formula M,[Fe(CN)6]y · zC6H12N4 · vH2O recently investigated by us. A structural model for the adducts is presented.

Crystal structures of hydrates of simple inorganic salts. II. Water-rich calcium bromide and iodide hydrates: CaBr2·9H2O, CaI2·8H2O, CaI2·7H2O and CaI2·6.5H2O

2014 ◽  
Vol 70 (9) ◽  
pp. 876-881 ◽  
Author(s):  
Erik Hennings ◽  
Horst Schmidt ◽  
Wolfgang Voigt
Keyword(s):  
Crystal Structure ◽  
Phase Diagram ◽  
Liquid Phase ◽  
Aqueous Solutions ◽  
Single Crystals ◽  
Crystal Structures ◽  
Room Temperature ◽  
Inorganic Salts ◽  
Solid Liquid

Single crystals of calcium bromide enneahydrate, CaBr2·9H2O, calcium iodide octahydrate, CaI2·8H2O, calcium iodide heptahydrate, CaI2·7H2O, and calcium iodide 6.5-hydrate, CaI2·6.5H2O, were grown from their aqueous solutions at and below room temperature according to the solid–liquid phase diagram. The crystal structure of CaI2·6.5H2O was redetermined. All four structures are built up from distorted Ca(H2O)8antiprisms. The antiprisms of the iodide hydrate structures are connected eitherviatrigonal-plane-sharing or edge-sharing, forming dimeric units. The antiprisms in calcium bromide enneahydrate are monomeric.

scholarly journals Syntheses and Crystal Structures of the New Ternary Barium Halide Hydrides Ba2H3X (X = Cl or Br)

2007 ◽  
Vol 62 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Olaf Reckeweg ◽  
Jay C. Molstad ◽  
Scott Levy ◽  
Francis J. DiSalvo
Keyword(s):  
Stainless Steel ◽  
Crystal Structures ◽  
Alkaline Earth ◽  
Metal Hydrides ◽  
Earth Metal ◽  
Solid State Reactions ◽  
Alkaline Earth Metal ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Compounds

Single crystals of the isotypic hydrides Ba2H3X (X = Cl or Br) were obtained by solid-state reactions of Ba, NaCl, NaNH2 and metallic Na, or Ba, NH4Br and Na, respectively, in sealed, silicajacketed stainless-steel ampoules. The crystal structures of the new compounds were determined by means of single crystal X-ray diffraction. Ba2H3Cl and Ba2H3Br crystallize in a stuffed anti CdI2 structure and adopt the space group P3̄m1 (No. 164) with the lattice parameters a = 443.00(6), c = 723.00(14) pm and a = 444.92(4), c = 754.48(14) pm, respectively. The hydride positions are derived by crystallographic reasoning and with the help of EUTAX calculations. The results are compared with known data for binary and ternary alkaline earth metal hydrides.

Crystal structures of hydrates of simple inorganic salts. I. Water-rich magnesium halide hydrates MgCl2·8H2O, MgCl2·12H2O, MgBr2·6H2O, MgBr2·9H2O, MgI2·8H2O and MgI2·9H2O

2013 ◽  
Vol 69 (11) ◽  
pp. 1292-1300 ◽  
Author(s):  
Erik Hennings ◽  
Horst Schmidt ◽  
Wolfgang Voigt
Keyword(s):  
Liquid Phase ◽  
Aqueous Solutions ◽  
Crystal Structures ◽  
Low Temperatures ◽  
Room Temperature ◽  
Inorganic Salts ◽  
Magnesium Halide ◽  
Magnesium Salts ◽  
Solid Liquid ◽  
Cation Complexes

The previously reported structures of the hydrates of simple inorganic salts that crystallize at room temperature are generally well determined. This is not true for water-rich hydrates, which crystallize at temperatures below 273 K. In this series, investigations of the crystal structures of water-rich hydrates crystallized from aqueous solutions at low temperatures are presented. Reported herein are the structures of a set of magnesium salts. Crystals of MgCl2·8H2O (magnesium dichloride octahydrate), MgCl2·12H2O (magnesium dichloride dodecahydrate), MgBr2·6H2O (magnesium dibromide hexahydrate), MgBr2·9H2O (magnesium dibromide nonahydrate), MgI2·8H2O (magnesium diiodide octahydrate) and MgI2·9H2O (magnesium diiodide nonahydrate) were grown from their aqueous solutions at temperatures below 298 K according to the solid–liquid phase diagrams. All structures are built up from Mg(H2O)6octahedra. Dimensions and angles in the hexaaqua cation complexes are very similar and variation is not systematic. The anions are incorporated into a specific network of O—H...Xhydrogen bonds.

THERMOLUMINESCENCE IN ALKALINE-EARTH DOPED KCl IRRADIATED AT ROOM TEMPERATURE

1976 ◽  
Vol 37 (C7) ◽  
pp. C7-158-C7-158
Author(s):  
A. RASCÓN ◽  
J. L. ALVAREZ RIVAS
Keyword(s):  
Alkaline Earth ◽  
Room Temperature

Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems: synthesis and crystal structures of Rb2[(UO2)(Cr2O7)(NO3)2] and two new polymorphs of Rb2Cr3O10

2021 ◽  
Vol 236 (1-2) ◽  
pp. 11-21
Author(s):  
Evgeny V. Nazarchuk ◽  
Oleg I. Siidra ◽  
Dmitry O. Charkin ◽  
Stepan N. Kalmykov ◽  
Elena L. Kotova
Keyword(s):  
Crystal Structure ◽  
Aqueous Solutions ◽  
Crystal Structures ◽  
Hydrothermal Treatment ◽  
Ambient Conditions ◽  
Screw Axis ◽  
3D Framework ◽  
Solution Acidity

Abstract Three new rubidium polychromates, Rb2[(UO2)(Cr2O7)(NO3)2] (1), γ-Rb2Cr3O10 (2) and δ-Rb2Cr3O10 (3) were prepared by combination of hydrothermal treatment at 220 °C and evaporation of aqueous solutions under ambient conditions. Compound 1 is monoclinic, P 2 1 / c $P{2}_{1}/c$ , a = 13.6542(19), b = 19.698(3), c = 11.6984(17) Å, β = 114.326(2)°, V = 2867.0(7) Å3, R 1 = 0.040; 2 is hexagonal, P 6 3 / m $P{6}_{3}/m$ , a = 11.991(2), c = 12.828(3) Å, γ = 120°, V = 1597.3(5) Å3, R 1 = 0.031; 3 is monoclinic, P 2 1 / n $P{2}_{1}/n$ , a = 7.446(3), b = 18.194(6), c = 7.848(3) Å, β = 99.953(9)°, V = 1047.3(7) Å3, R 1 = 0.037. In the crystal structure of 1, UO8 bipyramids and NO3 groups share edges to form [(UO2)(NO3)2] species which share common corners with dichromate Cr2O7 groups producing novel type of uranyl dichromate chains [(UO2)(Cr2O7)(NO3)2]2−. In the structures of new Rb2Cr3O10 polymorphs, CrO4 tetrahedra share vertices to form Cr3O10 2− species. The trichromate groups are aligned along the 63 screw axis forming channels running in the ab plane in the structure of 2. The Rb cations reside between the channels and in their centers completing the structure. The trichromate anions are linked by the Rb+ cations into a 3D framework in the structure of 3. Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems is discussed.

scholarly journals Effective replacement of cetyltrimethylammonium bromide (CTAB) by mercaptoalkanoic acids on gold nanorod (AuNR) surfaces in aqueous solutions

Nanoscale ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 658-668 ◽  
Author(s):  
Rafael del Caño ◽  
Jose M. Gisbert-González ◽  
Jose González-Rodríguez ◽  
Guadalupe Sánchez-Obrero ◽  
Rafael Madueño ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Gold Nanorods ◽  
Ligand Exchange ◽  
Cetyltrimethylammonium Bromide ◽  
Gold Nanorod ◽  
Experimental Conditions ◽  
Seed Mediated ◽  
The Stability

The highly packed cetyltrimethylammonium bromide bilayer on the surface of gold nanorods synthesized by the seed-mediated procedure hampers the complete ligand exchange under experimental conditions that preserves the stability of the dispersions.

Distorted chiolite crystal structures of α-Na5M3F14 (M=Cr,Fe,Ga) studied by X-ray powder diffraction

2003 ◽  
Vol 18 (2) ◽  
pp. 128-134 ◽  
Author(s):  
A. Le Bail ◽  
A.-M. Mercier
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Rietveld Refinements ◽  
Space Group ◽  
X Ray ◽  
Precise Characterization

The crystal structures of the chiolite-related room temperature phases α-Na5M3F14 (MIII=Cr,Fe,Ga) are determined. For all of them, the space group is P21/n, Z=2; a=10.5096(3) Å, b=7.2253(2) Å, c=7.2713(2) Å, β=90.6753(7)° (M=Cr); a=10.4342(7) Å, b=7.3418(6) Å, c=7.4023(6) Å, β=90.799(5)° (M=Fe), and a=10.4052(1) Å, b=7.2251(1) Å, c=7.2689(1), β=90.6640(4)° (M=Ga). Rietveld refinements produce final RF factors 0.036, 0.033, and 0.035, and RWP factors, 0.125, 0.116, and 0.096, for MIII=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P21/n space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds.

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