Extraction and coordination studies of the unexplored bifunctional ligand carbamoyl methyl sulfoxide (CMSO) with uranium(VI) and cerium(III) nitrates. Synthesis and structures of [UO2(NO3)(2)((PhSOCH2CONBu2)-Bu-i)] and [Ce(NO3)(3)(PhSOCH2CONBu2)(2)]

The bifunctional carbamoyl methyl sulfoxide ligands, PhCH2SOCH2CONHPh (L-1), PhCH2SOCH2CONHCH2Ph (L-2), (PhSOCH2CONPr2)-Pr-i (L-3), PhSOCH2CONBu2 (L-4), (PhSOCH2CONBu2)-Bu-i (L-5) and PhSOCH2CON(C8H17)(2) (L-6) have been synthesized and characterized by spectroscopic methods. The selected coordination chemistry of L-1, L-3, L-4 and L-5 with [UO2(NO3)(2)] and [Ce(NO3)(3)] has been evaluated. The structures of the compounds [UO2(NO3)(2)((PhSOCH2CONBu2)-Bu-i)] (10) and [Ce(NO3)(3)(PhSOCH2CONBu2)(2)] (12) have been determined by single crystal X-ray diffraction methods. Preliminary extraction studies of ligand L-6 with U(VI), Pu(IV) and Am(III) in tracer level showed an appreciable extraction for U(VI) and Pu(IV) in up to 10 M HNO3 but not for Am(III). Thermal studies on compounds 8 and 10 in air revealed that the ligands can be destroyed completely on incineration. The electron spray mass spectra of compounds 8 and 10 in acetone show that extensive ligand distribution reactions occur in solution to give a mixture of products with ligand to metal ratios of 1 : 1 and 2 : 1. However, 10 retains its solid state structure in CH2Cl2.

New copper(I) cyanide networks: interpenetration, self-penetration and polymorphism

The structures Of four alkali-metal copper (I) cyanides, KCu2(CN)(3)(H2O)-H-.-II (I), K2Cu3(CN)(5) (II), CsCu3(CN)(4) (III) and KCu3(CN)(4) (IV) are described. Three of these, ((II)-(IV)), with previously unknown ACN:CuCN ratios have new copper-cyanide frameworks, whilst (1) is a new polymorph of KCu2(CN)(3)(H2O)-H-.. These structures are discussed in terms of assembly from the simple building units Cu(CN)(2/2), Cu(CN)(3/2), Cu(CN)(2/2)(CN)(1/1) and Cu(CN)(4/2). Compounds (I), (II) and (III) are layered materials based on (6,3) nets containing (CuCN)(6) rings (I) and (CuCN)(8) rings (II) and (III). In compound (IV), (4,4) nets containing (CuCN)(12) rings link to generate a three-dimensional network. Both (III) and (IV) are examples of interpenetrating solids in which two and four identical networks interweave, respectively. These materials illustrate the structural versatility of copper (I) in cyanide frameworks. (c) 2006 Elsevier SAS. All rights reserved.

Solvothermal syntheses, crystal structures and properties of five new thloantimonates(III) containing the [Sb4S7](2-) anion

Five new thioantimonates have been synthesized in the presence of organic amines under solvothermal conditions and their structures determined by single-crystal X-ray diffraction. All of the compounds are layered and contain antimony-sulphide anions of stoichiometry [Sb4S7](2-), but the structure of the anion formed is dependent on the amine used in synthesis. (H3N(CH2)(4)NH3)[Sb4S7] (1) contains [Sb4S7](2-) double chains directed along [010]. Weak interchain Sb-S interactions between neighbouring chains cause the double chains to pack into layers in the ab plane. In the [001] direction, the layers of double chains alternate with doubly protonated diaminobutane molecules to which the chains are hydrogen bonded. Compounds of general formula (TH)(2)[Sb4S7] (T= CH3(CH2)(2)NH2 (2), (CH3)(2)CHNH2 (3), CH3(CH2)(3)NH2 (4) and CH3(CH2)(4)NH2 (5)) adopt a more complex structure in which [Sb3S8](7-) units are linked by Sb-3(3-) pyramids to form chains, which in turn are bridged by sulphur atoms to create sheets containing large heterorings. Pairs of such sheets form double layers of four atoms thickness that are stacked along [001]. Protonated amine molecules are located between anionic antimony-sulphide layers to which they are hydrogen bonded. Thermal analysis reveals that the decomposition temperature of materials containing [Sb4S7](2-) anions is dependent both on the structure of the anion, the lowest decomposition temperature being that of the low-dimensional phase (1) and on the identity of the amine, the decomposition temperature decreasing with an increasing number of carbon atoms and decreasing density. (c) 2005 Elsevier Inc. All rights reserved.

Synthesis, characterization and physical properties of the skutterudites YbxFe2Ni2Sb12 (0≤x≤0.4)

The skutterudites YbxFe2Ni2Sb12 (0≤x≤0.4) have been prepared by solid-state reaction and characterised by powder X-ray diffraction. The compounds crystallise in the cubic space group Im View the MathML source3¯ (a≈9.1 Å) with Yb atoms partially filling the voids in the skutterudite framework. A neutron time-of-flight diffraction experiment for Fe2Ni2Sb12 confirms the disorder of Fe and Ni atoms on the transition-metal site. Electrical resistivity, Seebeck coefficient and thermal conductivity measurements indicate that the thermoelectric performance of the skutterudites shows a marked dependence on the Yb content. Magnetic measurements over the temperature range 2≤T/K≤300 show paramagnetic behaviour for all compounds. Decomposition studies under an oxidising atmosphere at elevated temperatures have also been carried out by thermogravimetric analysis.

Synthesis and thermoelectric properties of the new skutterudites Yb x Fe2Ni2Sb12 (0 ≤ x ≤ 0.4)

The family of materials Yb x Fe2 Ni 2Sb12 (0 ≤ x ≤ 0.4) has been prepared by solid-state synthesis from the pure elements and characterized by powder X-ray diffraction. These materials crystallize in the skutterudite structure, with the framework voids partially filled with Yb atoms. Electrical resistivity, Seebeck coefficient and thermal conductivity measurements have been performed on hot-pressed samples, and indicate that the thermoelectric performance is significantly improved by increasing the Yb content. The decomposition of the compounds under oxidizing atmosphere at elevated temperatures has also been studied by thermogravimetric analysis. The physical properties and thermal stability of the new compounds are further discussed in comparison with those of the reported isostructural and isoelectronic Yb x Co4Sb12 (0 ≤ x ≤ 0.19).