The First Fully Fluorinated Organically Templated Materials:  Synthesis, Structures, and Physical Properties of [H₃N(CH₂)₃NH₃]U₂F₁₀·2H₂O, [H₃N(CH₂)₄NH₃]U₂F₁₀·3H₂O, [H₃N(CH₂)₆NH₃]U₂F₁₀·2H₂O, and [HN(CH₂CH₂NH₃)₃]U₅F₂₄

Abstract

A series of new layered uranium(IV) fluorides have been prepared under hydrothermal conditions from UO2, HF, and H3PO4 by using H2N(CH2) n NH2 (n = 3, 4, or 6), and N(CH2CH2NH2)3 as structure-directing agents. [H3N(CH2)3NH3]U2F10·2H2O (UFO-1), [H3N(CH2)4NH3]U2F10·3H2O (UFO-2), [H3N(CH2)6NH3]U2F10·2H2O (UFO-3), and [HN(CH2CH2NH3)3]U5F24 (UFO-4) have been characterized by single-crystal X-ray diffraction, thermogravimetric analysis, BET isotherms, and magnetic susceptibility measurements. UFO-1, 2, 3, and 4 contain negatively charged uranium fluoride (UF) layers constructed from linked UF n polyhedra separated by charge balancing organic cations and occluded water molecules. In UFO-1, 2, and 3, the layers are constructed from equivalent UF9 tricapped trigonal prisms that share three edges and two corners, whereas UFO-4 contains both UF8 bicapped trigonal prisms and UF9 tricapped trigonal prisms. We have demonstrated that the interlamellar organic cations in these materials can be ion-exchanged with a large variety of alkali, alkaline earth, and transition metal cations, thus providing a low-temperature route to new condensed mixed metal uranium fluorides. The magnetic susceptibility data indicate that UFO-1, 2, and 3 exhibit Curie-Wiess behavior between room temperature and 20 K. [Crystal data: UFO-1, monoclinic, space group P21/c (no. 14), a = 10.715(1) Å, b = 7.097(1) Å, c = 8.767(1) Å, β = 93.804(6)°, V = 665.21(1) Å3 (T = 150 K), Z = 2, R(F) = 5.42%, R w (F) = 6.79%; UFO-2, triclinic, space group P1̄ (no. 2), a = 12.024(2) Å, b = 7.149(3) Å, c = 8.765(2) Å, α = 90.063(4)°, β = 107.133(5)°, γ = 92.098(3)°, V = 719.49(3) Å3 (T = 150 K), Z = 2, R(F) = 8.05%, R w (F) = 10.11%; UFO-3, monoclinic, space group P21/c (no. 14), a = 13.800(2) Å, b = 7.056(1) Å, c = 8.720(1) Å, β = 108.338(6)°, V = 805.97(2) Å3 (T = 150 K), Z = 2, R(F) = 3.64%, R w (F) = 4.65%; UFO-4, triclinic, space group P1̄ (no. 2), a = 11.534(2) Å, b = 11.532(4) Å, c = 9.634(2) Å, α = 104.034(4)°, β = 101.112(8)°, γ = 93.922(4)°, V = 1210.9(5) Å3 (T = 150 K), Z = 2, R(F) = 6.12%, R w (F) = 8.19%.]

Old materials with new tricks: multifunctional open-framework materials

“…In spite of the numerous inorganic families and examples of magnetic openframework materials so far described along this review as well as their enormous progress experienced over the last 15 years, the search for new inorganic magnetic open-framework compounds can be still considered at an early stage. Indeed, recent examples of magnetic silicates, 202 germanates, 203 fluorides, 17,204 selenites, 205 polyoxovanadates, 206 sulfides 207 and oxochlorides 16 with open-framework structures seems to confirm such tendency by opening new and successful synthetic routes. From a magnetic point of view, most of them still behave as paramagnets with weak antiferromagnetic interactions at low temperatures.…”

“…In addition to the family of phosphates with a large list of different metal ions (gallium, 5 tin, 6 iron, 7 cobalt, 8,9 vanadium, 10 indium, 11 boron, 12 manganese, 13 molybdenum, 14 etc. ), more recently new oxygen-containing porous materials such as phosphites, 15 oxofluorides and oxochlorides, 16 fluorides, 17 nitrides, 18 sulfates, 19 sulfides, 20 selenites, 21 halides, 22 germanates, 23 arsenates, 24 and cyanides 25 have been obtained.…”

The theory-driven quest for a novel family of superconductors: fluorides

“…AgF 2 -organic hybrids would be similar to the well-known layered uranium and thorium fluorides (UFO 143 and TFO 144 ), where protonated amines serve as a structure-directing reagent. Preparation of such layered compounds will be limited by the ability of the nitrile ligand to withstand oxidation; 145 recollect that AgF 2 is the most strongly oxidizing of all known metal difluorides.…”

Facile Ionic Liquid‐Assisted Strategy for Direct Precipitation of Eu2+‐Activated Nanophosphors under Ambient Conditions

“…Moreover, another remarkable advantage of our preparation method is that suitable ionic liquids can also be used as fluorine source . In general, the proper preparation of high quality fluoride materials even in bulk sizes needs the utilization of elemental fluorine or HF as starting compounds, which are rather difficult and inconvenient methods. With the use of fluoride containing ionic liquids as solvent and also as starting compound, several fluoride materials not limited to phosphors are expected to be accessible via our method as we very recently reported in ref.…”