Solvated Actinoids: Methanol, Ethanol, and Water Adducts of Thorium and Uranium Tetrachloride

The solvent adducts of the tetravalent actinoid chlorides ThCl4 and UCl4 have been isolated with methanol as [ThCl4(MeOH)(4)] 1 and [UCl4(MeOH)(4)] 2, and with ethanol as [ThCl4(EtOH)(4)] 3 and [UCl4(EtOH)(4)] 4. In hydrochloric acid [ThCl2(H2O)(7)](Cl)(2)(H2O)(2) 5 forms, which is isotypic to the known [UCl2(H2O)(7)](Cl)(2)(H2O)(2) 6. The adducts have been analysed using SXRD, IR, CHN, TGA-MS and PXRD. The material can be isolated from saturated organic (1-4) or acidic aqueous (5-6) solutions, however, drying of the isolated material results in loss of HCl and the formation of oxide species, confirmed by the isolation of U3O8 after complete thermal decomposition

Thiosemicarbazone Complexes of Uranium(IV)

The first homoleptic thiosemicarbazone complexes of uranium were isolated by reacting uranium tetrachloride in a salt metathesis or acid-base reaction with four equivalents of Na(BzTSC) or H(BzTSC) (BzTSC=benzylthiosemicarbazone), carrying a non-methylated (L1), monomethylated (L2) or dimethylated (L3) terminal amino group, in moderate yields. [U(BzTSCNH(2))(4)] (1), [U(BzTSCNH(CH3))(4)] (2) and [U(BzTSCN(CH3)(2))(4)] (3) show a remarkable stability towards air, with oxidation potentials in THF between +0.43 and +0.53 V and reduction potentials between -2.53 and -2.67 V vs. ferrocene/ferrocenium. The simple methylation of the terminal amino group of the ligand allows for controlled changes in the coordination environments of the complexes. Thermogravimetric analyses indicate that the complexes are stable up to 155 degrees C

Heterobimetallic uranyl(vi) alkoxides of lanthanoids: formation through simple ligand exchange

Lanthanoid and actinoid silylamides are versatile starting materials. Herein we show how a simple ligand exchange with tert-butanol leads to the formation of the first trimeric heterobimetallic uranyl(vi)-lanthanoid(iii) alkoxide complexes. The mu(3) coordination of the endogenous uranyl oxo atom results in a significant elongation of the bond length and a significant deviation from the linear uranyl arrangement

Synthesis, characterization, and high-pressure studies of a 3D berkelium(iii) carboxylate framework material

A berkelium(iii) mellitate, Bk-2[C-6(CO2)(6)](H2O)(8)center dot 2H(2)O, was synthesized and rapidly crystallized by reacting mellitic acid, C-6(CO2H)(6), and BkBr3 center dot nH(2)O in an aqueous medium. Single crystal X-ray diffraction shows that the compound crystallizes as a three-dimensional framework isostructural with Pu(iii), Am(iii), and Cm(iii) mellitates. UV-vis-NIR spectroscopic studies as a function of pressure were performed using a diamond anvil cell and show that the 5f -> 5f transitions of Bk3+ display enhanced hypsochromic shifting when compared to other An(iii) mellitates

Two Neptunium(III) Mellitate Coordination Polymers: Completing the Series Np-Cf of Trans-Uranic An(III) Mellitates

Two neptunium(III) mellitates, 237Np2(mell)(H2O)9 center dot 1.5H2O (Np-1 alpha) and 237Np2(mell)(H2O)8 center dot 2H2O (Np-1 beta), have been synthesized from 237NpCl4(dme)2 by reduction with KC8 and subsequent reaction with an aqueous solution of mellitic acid (H6mell). Characterization by single-crystal X-ray crystallography and UV-vis-NIR spectroscopy confirms that the neptunium is in its +3 oxidation state and both polymorphs are isostructural to the previously reported plutonium mellitates. Of the two morphologies, Np-1 alpha is indefinitely stable in air, while Np-1 beta slowly oxidizes over several months. This is due to the change in the energy of the metal-ligand charge-transfer absorption exhibited by these compounds attributed to differing numbers of carboxylate bonds to Np(III), where in Np-1 beta the energy is low enough to result in spontaneous oxidation

Ammonium Pertechnetate in Mixtures of Trifluoromethanesulfonic Acid and Trifluoromethanesulfonic Anhydride

Ammonium pertechnetate reacts in mixtures of trifluoromethanesulfonic anhydride and trifluoromethanesulfonic acid under final formation of ammonium pentakis(trifluoromethanesulfonato)oxidotechnetate(V), (NH4)(2)[TcO(OTf)(5)]. The reaction proceeds only at exact concentrations and under the exclusion of air and moisture via pertechnetyl trifluoromethanesulfonate, [TcO3(OTf)], and intermediate Tc-VI species. Tc-99 nuclear magnetic resonance (NMR) has been used to study the Tc-VII compound and electron paramagnetic resonance (EPR), Tc-99 NMR and X-ray absorption near-edge structure (XANES) experiments indicate the presence of the reduced technetium species. In moist air, (NH4)(2)[TcO(OTf)(5)] slowly hydrolyses under formation of the tetrameric oxidotechnetate(V) (NH4)(4)[{TcO(TcO4)(4)}(4)] .10 H2O. Single-crystal X-ray crystallography was used to determine the solid-state structures. Additionally, UV/Vis absorption and IR spectra as well as quantum chemical calculations confirm the identity of the species