Crystal Structure of Sodium Perchloratotriacetatoneptunate(V) Monohydrate Na<Subscript>3</Subscript>NpO<Subscript>2</Subscript>(OOCCH<Subscript>3</Subscript>)<Subscript>3</Subscript>ClO<Subscript>4</Subscript> · H<Subscript>2</Subscript>O

The crystal structure of Na₃NpO₂(OOCCH₃)₃ClO₄ · H₂O was studied by single-crystal X-ray diffraction method. The structure is composed of the complex anions NpO₂(OOCCH₃)₃]²⁻, perchlorate anions, Na cations, and water molecules. The oxygen environment of Np(V) is a hexagonal bipyramid whose equatorial plane is formed by the oxygen atoms of three acetate ions. In addition to the acetate anions, the structure contains the perchlorate ion whose oxygen atoms, except for one, are included in the coordination environment of Na⁺ cations.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 8, 2005, pp. 636–640.Original Russian Text Copyright © 2005 by Charushnikova, Fedoseev, Starikova.     

Crystal structure of a new neodymium hexamolybdotellurate,Nd<Subscript>2</Subscript>TeMo<Subscript>6</Subscript>O<Subscript>24</Subscript> · 19H<Subscript>2</Subscript>O

The crystal structure of a new compound, namely, Nd₂TeMo₆O₂₄ · 19H₂O, is determined using X-ray diffraction. The crystal has a chain structure and consists of [Nd₂TeMo₆O₂₄ · 14H₂O]_n neutral chains aligned parallel to the [010] direction and crystallization water molecules. In a chain, each Nd atom links two heteropoly anions. The Nd³⁺ environment includes seven water molecules and two oxygen atoms of the two heteropoly anions adjacent in the chain. The polyhedron is a monocapped tetragonal antiprism. In the previously studied complex of similar composition, namely, Nd₂TeMo₆O₂₄ · 18H₂O, the Nd coordination polyhedron has the shape of a tricapped trigonal prism formed by six water molecules and three oxygen atoms of the two heteropoly anions adjacent in the chain.     

Structure of uranyl complexes with acetylenedicarboxylic acid, K(H5O2)[UO2(OOCC≡CCOO)2 · H2O] · 2H2O and Cs2[UO2(OOCC≡CCOO)2 · H2O] · 2H2O

Uranyl complexes with acetylenedicarboxylic acid, K(H₅O₂)[UO₂L₂H₂O] · 2H₂O (I) and Cs₂[UO₂L₂H₂O] · 2H₂O (II), L²⁻ = C₄O ₄ ²⁻ were prepared for the first time. The composition and structure of the complexes were determined by X-ray diffraction. The crystal data are as follows: a = 16.254(12) ?, b = 13.508(8) ?, c = 7.683(6) ?, β = 90.91(7)°, space group C2/c, V = 1687(2) ?³ (I); a = 7.0745(10), b = 18.4246(10), c = 13.1383(10) ?, space group Abm2, V = 1712.5(3) ?³ (II). The structures of I and II are based on [UO₂L₂H₂O] _n ²⁻ anionic chains stretched along the [101] direction (I) or [010] direction (II). In I and II, the uranium coordination polyhedron is a pentagonal bipyramid in which the equatorial environment of the uranyl ions is formed by the oxygen atoms of the four L²⁻ anions and the water molecule. The L²⁻ anions in I and II are bidentate bridging ligands connecting two uranium atoms that are next to each other in the anionic chain; their coordination capacity is equal to 2. In I, the K⁺ and H₅O ₂ ⁺ cations are outer-sphere species. The latter form hydrogen bonds combining the anionic chains shifted by translation b with respect to each other. The [UO₂L₂H₂O] _n ²⁻ chains in I are surrounded by the potassium and oxonium cations; in II, these are combined by hydrogen bonds into anionic layers between which Cs⁺ cations are arranged. The IR spectrum of compound II was measured and interpreted. Original Russian Text ? I.A. Charushnikova, A.M. Fedoseev, N.A. Budantseva, I.N. Polyakova, Ph. Moisy, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 1, pp. 63–69.     

Crystal Structures of Molecular Adducts between Uranyl Nitrate and 2,2′ : 6′,2′′-Terpyridine or 2,2′-Bipyridyl

Complexes of uranyl nitrate with aromatic molecular ligands : [UO₂Terpy(NO₃)₂] and (H₂Terpy)₂[UO₂(NO₃)₂(H₂O)₂](NO₃)₄ · 4H₂O (Terpy 2,2:6,2-terpyridine), (Hbipy)[UO₂(NO₃)₃] and [(UO₂)₂(Bipy)₂O₂(NO₃)₂] (Bipy—2,2-bipyridyl) and (HPy)₄[(UO₂)₂(NO₃)₄(OH)₂](NO₃)₂ (Py—pyridine) were characterized by X-ray diffraction analysis. In all these compounds, the U(VI) atom has the hexagonal bipyramidal environment. The U–O bond lengths in the UO₂ ²⁺ have close values. In the equatorial planes, the U–N bond lengths with the Bipy and Terpy ligands are identical, whereas the U–O bond lengths depend on the type of the ligand. The lengths of the equatorial bonds increase in the sequence U–N > U–O_nitr > U–O_hydr > U–O_perox. The geometric characteristics of the coordinated and solvate Terpy and Bipy molecules are different. The lengths of the N–O bonds in the NO₃ ^– groups depend on the participation of the O atom in the coordination of the central atom, the coordination mode, and the formation of hydrogen bonds.     

Neptunium(IV) Complex with Carbamide [Np(Urea)8]SiW12O40 · 2Urea · H2O: Synthesis,Crystal Structure,and Properties

The synthesis and crystal structure of [Np(Urea)₈]SiW₁₂O₄₀ · 2Urea · H₂O complex are reported. Crystallographic parameters: space groups C2/c, a = 18.972(5) Å, b = 18.891(5) Å, c = 16.654(4) Å, = 100.847(6)°, Z = 4, V = 5862(3) ų, (calcd) = 4.226 g/cm³. Thermal properties of this compound are studied; absorption spectra in the IR and visible regions are measured.     

Interaction of AnVI with Isothiocyanate Ion in Water‐Organic Media (An = U,Np, Pu)

Behavior of U^VI, Np^VI and Pu^VI in water‐acetonitrile solutions was studied spectrophotometrically with the successive addition of the polar organic ligands (dimethyl sulfoxide or hexamethylphosphoric triamide) and the NCS^– ion. The detected spectral effects – changes in the absorption intensity, bathochromic shifts in the absorption bands, the absence of isosbestic points, a change in the color of the solution – indicate complex competitive processes occurring in the studied solutions. In the case of Np^VI, its partial reduction to Np^IV by NCS^– ion is observed. Solid U^VI complex, [UO₂(HMPA)₂(NCS)₂], was isolated, its crystal structure was determined using X‐ray diffraction. In contrast to known AnO₂²⁺ compounds with the NCS^– ion, this complex exhibits tetragonal bipyramidal environment of the U atom. [UO₂(HMPA)₂(NCS)₂] is also characterized by UV/Vis, IR and luminescence spectroscopy.     

Crystal structure of a new basic nitrate of neodymium(III), [Nd6O(OH)8(H2O)14(NO3)6](NO3)2 · 2H2O

A new basic Nd³⁺ nitrate, [Nd₆O(OH)₈(H₂O)₁₄(NO₃)₆](NO₃)₂ · 2H₂O (I), is isolated in the crystal form and studied. Compound I differs from the basic Ln nitrates containing [Ln ₆O(OH)₈] clusters in that it involves a larger number of water molecules. The incorporation of additional water molecules is accompanied by changes in the coordination environment of one of the three crystallographically independent Nd³⁺ cations. Two cations have coordination polyhedra in the form of a monocapped tetragonal antiprism with a coordination number of 9, and the third cation has a polyhedron in the form of a bicapped tetragonal antiprism with a coordination number of 10. Original Russian Text ? I.A. Charushnikova, C. Den Auwer, 2007, published in Kristallografiya, 2007, Vol. 52, No. 2, pp. 248–251.     

Synthesis,crystal structure and some properties of new perrhenate and pertechnetate complexes of Nd and Am with 2,6-bis(tetramethylfurano)-1,2,4-triazin-3-yl)-pyridine,tris(2-pyridylmethyl)amine and N,N′-tetraethylmalonamide

The coordination complexes of trivalent f-element pertechnetates and perrhenates with some N-donor ligands were determined by using X-ray structural analysis: Nd³⁺ perrhenate with 2,6-bis(tetramethylfurano)-1,2,4-triazin-3-yl)-pyridine ([Nd(FBTP)₃ReO₄](ReO₄)₂ · 2H₂O (I)), tris(2-pyridylmethyl)amine ([Nd(TPA)(ReO₄)₃] (II)) and N,N′-tetraethylmalonamide ([Nd(TEMA)₄](ReO₄)₃ (III)). The coordination number of Nd is 10 in I, 9 in II and 8 in III. The complexes of Nd³⁺ pertechnetate and Am³⁺ pertechnetate with TPA have been also synthesized (Nd(TPA)(TcO₄)₃ (IV) and Am(TPA)(TcO₄)₃ (V)). The structure II does not change on replacement of perrhenate by pertechnetate and neodymium by americium.     

Crystal structure of neptunium(V) sulfate hexahydrate, (NpO2)2SO4 · 6H2O

Single crystals of (NpO₂)₂SO₄ · 6H₂O are obtained, and their structure is determined. The structure is built of NpO ₂ ⁺ dioxo cations, SO ₄ ^2? anions, and molecules of coordination and crystallization water. The NpO ₂ ⁺ ions are linked into cationic ribbons stretched along the [001] direction. In the ribbons, neptunoyl ions of one type act as monodentate ligands, whereas neptunoyl ions of the other type coordinate the neighboring neptunoyl groups by two oxygen atoms. The Np(1) and Np(2) atoms have oxygen environments in the shape of a pentagonal bipyramid whose equatorial plane consists of oxygen atoms of the neighboring dioxo cations, sulfate ions, and water molecules. The sulfate ion acts as a bidentate ligand bridging the two neighboring atoms Np(1) and Np(2). Six water molecules are revealed in the structure; one of them is a crystallization water molecule. Hydrogen bonds link cationic ribbons into a three-dimensional network.     

Crystal structure of complexes of pentavalent neptunium with 1,8-bis[2-(diphenylphosphinylmethyl)]phenoxy-3,6-dioxaoctane (L) and hexavalent actinides (U,Np, Pu) with 1,8-bis[2-(diphenylphosphinyl)]phenoxy-3,6-dioxaoctane (L<Superscript>1</Superscript>)

Complexes of pentaand hexavalent actinides with phosphoryl-containing podands incorporating a triethylene glycol fragment and 2-(diphenylphosphinyl)phenyl (L¹) or 2-(diphenylphosphinylmethyl)phenyl (L) end groups were synthesized and structurally characterized. The complexes can be described by the following formulas: [NpO₂L(C₂H₅OH)(NO₃)] (I) for pentavalent neptunium and [AnO₂(L¹)₂](OH)₂ · nH₂O (II), where An is U (IIa), Np (IIb), and Pu (IIc), for the isostructural compounds of hexavalent actinides. In I, L is a bidentate bridging ligand. The Np⁵⁺ coordination polyhedron is a pentagonal bipyramid. The bipyramid equatorial plane is formed by the oxygen atoms of two podands L, the bidentate nitrate ion, and the ethanol OH group. The oxygen atoms of the phosphoryl groups of the podand are involved in the coordination environment of two NpO₂⁺ cations where they connect the electrically neutral neptunoyl nitrate fragments to infinite chains along the [100] direction, which are in turn connected into ribbons by strong hydrogen bonds. The crystal of II consists of the complex cations [AnO₂(L¹)₂]²⁺, hydroxyl ions, and water molecules of crystallization. The environment of AnO₂²⁺ is formed by four ligands L¹ whose oxygen atoms form a tetragonal-bipyramidal coordination environment. Each of the two crystallographically independent ligands L¹ is connected to two AnO₂⁺ cations. This gives positively charged layers of actinyl cations perpendicular to the [010] direction connected by molecular ligands. The layers contain channels accommodating hydroxyl ions and crystallization water molecules.