On the synthesis of xenon(VI) fluorobismuthate(V)

The reaction between bismuth pentafluoride and excess liquid xenon hexafluoride yields a white diamagnetic solid XeF₆.BiF₅. On the basis of its Raman and infrared spectra the 1:1 compound could be formulated as XeF₅⁺BiF₆^-. The Strong fluorine-bridge interaction between cation and anion distorts the anion from O_h symmetry.     

Syntheses and vibrational spectra of xenon(VI) fluorozirconate(IV) and xenon(VI) fluorohafnate(IV)

Liquid xenon difluoride at 140°C does not react with zirconium or hafnium tetrafluorides, neither does liquid xenon hexafluoride at 60°C. Therefore reactions between the corresponding hydrazinium fluorometalates or ammonium fluorometalates and xenon difluoride and xenon hexafluoride, respectively, were carried out. N₂H₆ZrF₆ and N₂H₆HfF₆ react with xenon difluoride at 60°C again yielding only the corresponding tetrafluorides, while the analogous reaction with (NH₄)₂ZrF₆ and (NH₄)₂HfF₆ proceeds at 170°C yielding the corresponding ammonium pentafluorometalates, which are stable and do not react further with excessive xenon difluoride up to 200°C.The reaction between N₂H₆ZrF₆ or N₂H₆HfF₆ and xenon hexafluoride proceeds at room temperature yielding a series of thermally unstable compounds of the type mXeF₆.MF₄ (M = Zr, Hf) where m ? 6. The final products which are stable at room temperature are XeF₆.MF₄ (M = Zr,Hf). Spectroscopic evidence suggests that these compounds are salts of a XeF⁺₅ cation squashed between a polymeric anion of the type (MF₅)^x-_x.     

On the synthesis of xenon(II) fluorostannates(IV)

The reaction between tin difluoride and an excess of xenon difluoride at 140°C yields two new xenon(II) fluorostannates(IV): 3XeF_2^·4SnF₄ and XeF_2^·2SnF₄. The 3:4 compound can be written as a molecular adduct of XeF₂ and the 1:2 compound. On the basis of vibrational spectra, the 1:2 compound can be formulated as a XeF⁺ salt with a polymeric anion.     

On the syntheses of xenon fluoromanganates(IV)

The reactions between manganese difluoride and excessive XeF₂ or XeF₆ have been investigated at 120° and 60°C respectively. The following sets of compounds have been synthetized: nXeF₂. MnF₄ (n = 1, 0·5) and nXeF₆. MnF₄ (n = 4, 2, 1 0·5). The obtained compounds are paramagnetic and obey Curie-Weiss law in the temperature range from 4 to 290K. The oxidation number of manganese in all these compounds is +4 with μ_eff in the range from 3·8 to 4·1 B.M.     

Syntheses and vibrational spectra of xenon(VI) fluorogallate,xenon(VI) fluoroaluminate and xenon(VI) fluoroindate

Liquid xenon difluoride at 140°C does not react with aluminium, gallium, and indium trifluorides, neither does liquid xenon hexafluoride at 60°C. Therefore the reactions between the corresponding hydrazinium fluorometalates (N₂H₆AlF₅, N₂H₆GaF₅ and N₂H₅InF₄) and XeF₂ and XeF₆ were carried out. N₂H₆AlF₅, N₂H₆GaF₅ and N₂H₅InF₄ react with XeF₂ at 60°C (at 25°C in the case of indium) yielding only the corresponding trifluorides, while the reaction with XeF₆ proceeds at room temperature (at - 25°C in the case of indium) yielding XeF₆.2AlF₃, XeF₆.GaF₃ and xenon(VI) fluoroindate(III) contaminated with indium trifluoride. Spectroscopic evidence suggests that these compounds are salts of the XeF⁺₅ cation squashed between polymeric anions of the type (M₂F₇)^x-_x or (MF₄)^x-_x.     

On the syntheses of xenon fluorotitanates(IV)

The reactions between TiF₄ and excessive XeF₂ or XeF₆ have been investigated at 120°C and 60°C respectively. The following types of compounds were synthetized: nXeF₂. TiF₄ (n = 1·5, 1 and 0·5) and nXeF₆. TiF₄ (n = 4, 1 and 0·5). The obtained compounds are diamagnetic white solids.     

Vibrational analysis of the Raman,infrared and electronic spectra of hexafluoromanganate(IV)

From the Raman, infrared and electronic spectra all of the fundamental vibrational frequencies were determined for both the ground state⁴ A _2g and the excited² E _g In addition some fundamental frequencies were established for the⁴ T _2g and⁴ T _1g excited states from low temperature absorption spectra.

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Zusammenfassung Aus den Raman-, Infrarot- und Elektronenspektren wurden alle Grundschwingungsfrequenzen für den Grundzustand⁴ A _2g und den angeregten² E _g-Zustand bestimmt. Ferner wurden noch einige der entsprechenden Größen für die angeregten Zustände⁴ T _2g und⁴ T _1g aus Tieftemperatur-Absorptionsspektren ermittelt.

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Résumé Toutes les fréquences fondamentales de vibration ont été déterminées pour l'état fondamental⁴ A _2g et l'état excité² E _g à partir des spectres Raman, infra-rouge et électronique. De plus, certaines fréquences fondamentales des états excités⁴ T _2g et⁴ T _1g ont été obtenues à partir des spectres d'absorption à basse température.

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Dedicated to the memory of Prof. Hans-Ludwig Schläfer.     

Selective hydrothermal synthesis of ammonium vanadates(V) and (IV,V)

Transition Metal Chemistry - The reduction of vanadium pentoxide with formamide under hydrothermal–microwave treatment at 180–210 °C allows for the selective synthesis of...     

Cerium(IV) ammonium nitrate catalyzed synthesis of α-dehydro-β-amino esters

α-Dehydro-β-amino esters have been synthesized regioselectively from acetates of Baylis-Hillman adducts with amines in the presence of a catalytic amount of ceric ammonium nitrate (CAN) in good yield. The regioselectivity does not differ with respect to the polarity of the solvent.     

Zirconium(IV) Thorium(IV) and Dioxouranium(VI) Complexes of Salicylidene o-Aminobenzothiol

Salicylidene-o-aminobenzothiol and its 5-chloro and 5-bromo derivatives, dibasic tridentate Schiff bases, dervied from the condensation of o-aminothiol and Salicylaldehyde, 5-chloro salicylaldehyde and 5-bromo salicylaldehyde, were used for coordination with Zr(IV), Th(IV) and UO₂(VI) metal inos. The I:I (metal-ligand) stoichiometry of these complexes is shown by elemental analysis and conductometric titrations. Molecular structure of these complexes are proved by Infra-red spectroscopy and thermogravimetric analysis. Magnetic susceptibility measurements of Zr(IV), Th(IV) and UO₂(VI) complexes show their diamagnetic and octahedral geometry. Results show that all the complexes have solvent molecules in coordination with metal ion.     

Facile synthesis of 1,2,3-tricarbonyls from 1,3-dicarbonyls mediated by cerium(IV) ammonium nitrate

A mild and efficient protocol for the synthesis of vicinal tricarbonyl compounds from β-dicarbonyls in a single step using cerium(IV) ammonium nitrate as a catalytic oxidant is described. Ease of execution, wide substrate scope and the suitability for the synthesis of commercially important compounds like ninhydrin, alloxan and oxoline make this reaction particularly noteworthy.     

Mixed-valent uranium(IV,VI) diphosphonate: synthesis, structure, and spectroscopy

A mixed-valent uranium(IV,VI) diphosphonate, (H(3)O)(2)(UO(2))(3)U(H(2)O)(2)[CH(2)(PO(3))(2)](3)·6H(2)O (UC1P2S), has been synthesized under hydrothermal conditions. S-2-butanol was used to reduce uranium VI to IV. The tetravalent uranium centers adopt eight-coordinate geometries, while hexavalent uranyl units are all tetragonal bipyramids. The UV-vis-NIR spectrum of UC1P2S shows absorption features for both U(VI) and U(IV).     

Dioxouranium(VI) and oxouranium(IV) fluorosulphates and double fluorosulphates of uranium(IV)

UO₂(SO₃F)₂, UO(SO₃F)₂, U(SO₃F)₄ and MU(SO₃F)₆, MMg, Zn have been prepared by reacting UO₂(O₂CCH₃)₂, U(O₂CCH₃)₄, U(O₂CCF₃)₄ and MU(O₂CCH₃)₆ with HSO₃F. The analysis of i.r. spectral data of UO₂(SO₃F)₂, UO(SO₃F)₂ and MU(SO₃F)₆ shows the presence of only one type of SO₃F group with reduced symmetry C_s. In U(SO₃F)₄, two SO₃F groups are bidentate, while the other two are monodentate. A sharp band at 925 cm^?1 in UO₂(SO₃F)₂ is diagnostic of UO₂²⁺. The diffuse reflectance spectra of UO(SO₃F)₂, U(SO₃F)₄ and MU(SO₃F)₆ reveal hexacoordination of U(IV), while the magnetic moments of these compounds support the existence of U(IV). UO₂(SO₃F)₂ and UO(SO₃F)₂ decompose thermally in a single step with the evolution of SO₂F₂ and formation of their respective sulphates.