Synthesis and structures of two uranyl β-diketonate complexes [UO2(DBM)2(DEDPU)] and [UO2(PMBP)2(DEDPU)]

Two new uranyl β-diketonate complexes [UO₂(DBM)₂(DEDPU)] (1) and [UO₂(PMBP)₂(DEDPU)](CH₃C₆H₅)_0.5 (2), (HDBM?=?dibenzoylmethane, HPMBP?=?1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, DEDPU?=?N,N′-diethyl-N,N′-diphenylurea) were synthesized and characterized. The coordination geometries of the uranyl atoms in 1 and 2 are distorted pentagonal bipyramidal, coordinated by one oxygen atom of DBDPU molecule and four oxygen atoms of two chelating DBM molecules in 1 and PMBP molecules in 2.     

Syntheses and structures of two new uranyl complexes [UO2(DPDPU)2(NO3)2](C6H5CH3) and [UO2(PMBP)2(DPDPU)](CH3C6H4CH3)0.5

Two new uranyl complexes [UO₂(DPDPU)₂(NO₃)₂](C₆H₅CH₃) (1) and [UO₂(PMBP)₂ (DPDPU)](CH₃C₆H₄CH₃)_0.5 (2), (DPDPU?=?N,N′-dipropyl-N,N′-diphenylurea, HPMBP?= 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5) were synthesized and characterized. The coordination geometry of the uranyl atom in 1 is distorted hexagonal bipyramidal, coordinated by two oxygen atoms of two DPDPU molecules and four oxygen atoms of two bidentate nitrate groups. The coordination geometry of the uranyl atom in 2 is distorted pentagonal bipyramidal, coordinated by one oxygen atom of one DPDPU molecule and four oxygen atoms of two chelating PMBP molecules.     

Synthesis,structures, and spectroscopic properties of Hg(II) complexes of bidentate NN and tridentate NNO Schiff-base ligands

Reactions of HgX₂ (X?=?Cl, N₃, NO₃) with (E)-2-methoxy-N-(pyridin-2-ylmethylene)aniline (L¹) and (E)-4-methoxy-N-(pyridin-2-ylmethylene)aniline (L²) in ethanol gave two monomers, [HgL¹(Cl)₂] (1) and [HgL²(NO₃)₂(DMSO)] (5), and three coordination polymers, {[HgL¹(N₃)₂]₂·Hg(N₃)₂}_n (2), [HgL²(Cl)₂]_n (3), and [HgL²(NO₃)₂]_n·nCH₃CN (4). Compounds 1–5 were characterized by elemental analysis, IR, NMR spectroscopy, and single-crystal X-ray diffraction. The common feature of monomeric 1 and 5 is the presence of intra- and intermolecular Hg–O bonds. In the absence of these, polymeric structures arise as a result of azide, chloride, and nitrate bridging in 2, 3, and 4, respectively. Fluorescent properties of 1–5 were also investigated.     

Phase equilibria at various temperatures in the ternary liquid system containing solvates of thorium(IV) and uranyl(VI) nitrates with tri-n-butyl phosphate and tetradecane

The phase diagram of the ternary liquid system [Th(NO₃)₄(TBP)₂]-[UO₂(NO₃)₂(TBP)₂]-tetradecane (where TBP stands for tri-n-butyl phosphate) has been investigated at temperatures from 298.15 to 333.15 K. The ternary liquid system is characterized by a region of homogeneous solutions and a region of two-phase liquid systems (stratified systems). One phase is enriched with solvates [Th(NO₃)₄(TBP)₃] and [UO₂(NO₃)₂(TBP)₂] (phase I), and the other is enriched with tetradecane (phase II). The temperature (T = 298.15–333.15 K) does not substantially affect the two-phase region. In the two-phase systems, the preferential distribution of [UO₂(NO₃)₂(TBP)₂] into phase I is observed in spite of the fact that the binary system [UO₂(NO₃)₂(TBP)₂]-tetradecane is a single phase at all temperatures investigated. The distribution of [UO₂(NO₃)₂(TBP)₂] into phase I leads to the redistribution of [Th(NO₃)₄(TBP)₂] into phase II. At all temperatures investigated, the critical solution points of the ternary liquid system have compositions with close contents of the solvates [Th(NO₃)₄(TBP)₂] and [UO₂(NO₃)₂(TBP)₂].     

Crystal structure of two new molecular adducts of uranyl nitrate with 2,2′-6,2″-terpyridine

The crystal structures of two uranyl nitrate complexes with 2,2′-6,2″-terpyridine (Trpy), [(UO (Trpy)-[(UO₂)₂(Trpy)₂(OH)₂][UO₂(NO₃)₂(OH)₂] · 2CH₃OH (I) and [(UO₂)₂(Trpy)₂(OH)₂]₂[UO₂(NO₃)₃(H₂O)](NO₃)₃ · 3H₂O (II), were studied. Compound I consists of the centrosymmetric dimeric cations [(UO₂)₂(Trpy)₂(OH)₂]²⁺, the anions [UO₂(NO₃)₂(OH)₂]^2?, and solvation methanol molecules. Complex II consists of dimeric cations [(UO₂)₂(Trpy)₂(OH)₂]²⁺, the complex anions [UO₂(NO₃)₃(H₂O)]^?, nitrate anions, and water molecules of crystallization. The uranium atom in the [UO₂(NO₃)₃(H₂O)]^? anion in II has an unusual coordination polyhedron representing a hexagonal bipyramid in which one oxygen atom in the equatorial plane is replaced by two atoms equidistant from this plane.     

Phase equilibria in ternary liquid systems containing solvates of lutetium(III) and uranyl(VI) nitrates with tri-n-butyl phosphate and tetradecane at various temperatures

The phase diagram has been studied for the ternary liquid system (TLS) [Lu(NO₃)₃(TBP)₃]-[UO₂(NO₃)₂(TBP)₂]-tetradecane at T = 298.15–333.15 K. There are fields of homogeneous and two-phase solutions in the system. One phase (phase I) is enriched in [Lu(NO₃)₃(TBP)₃] and [UO₂(NO₃)₂(TBP)₂]; the other (phase II) is enriched in tetradecane. Critical compositions in the system depend on temperature. [UO₂(NO₃)₂(TBP)₂] tends to be distributed to phase I, despite the fact that the binary system [UO₂(NO₃)₂(TBP)₂[-tetradecane is a single phase at all temperatures studied.     

Filling the equatorial garland of uranyl ion: its content and limitations

Crystal structure determinations on the uranyl ion complexes [H₂N(CH₃)₂]₂[UO₂(bpdc)₂], (1), (bpdc?=?2,2′-bipyridine-3,3′-dicarboxylate), [pyH]₂[UO₂(btfac)(NO₃)₂](NO₃), (2), (btfac?=?1-phenyl-4,4,4-trifluorobutane-1,3-dionate), [H₂dabco][UO₂(nta)]₂·3H₂O, (3), (dabco?=?1,4-diazabicyclo[2.2.2]octane; nta?=?nitrilotriacetate) and [Ni(cyclam)UO₂(edta)]^.2H₂O, (4), (cyclam?=?1,4,8,11-tetrazacyclotetradecane; edta?=?ethylenediaminetetraacetate) have provided further examples of U(VI) in tetragonal-, pentagonal and hexagonal-bipyramidal coordination environments. Consideration of each structure within the context of those of known relatives has been used to assess the influence of factors in addition to repulsions within the primary coordination sphere on the equatorial coordination number of U(VI).

     

UO22+-polycarboxylate heterometallic complexes: structure,spectra, and photocatalytic properties

[Cu₂(UO₂)₄(suc)₄(pac)₄] (1), [(Cu(H₂O)₂)(4,4′-bipy)₂][(UO₂)₂(H₂O)₂(Hca)₂]·3H₂O (2), and [(Cu(H₂O)₂)(UO₂)(bta)]·4H₂O (3) were synthesized by the reaction of succinic acid and 3-pyridinecarboxylic acid, citric acid and 4,4′-bipyridine, or 1,2,4,5-benzenetetracarboxylic acid ligands with Cu(NO₃)₂·3H₂O and UO₂(CH₃COO)₂·2H₂O. The complexes were characterized by IR and UV–vis spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction, and photoluminescence spectroscopy. Photocatalytic activities of the complexes were also investigated.     

Synthesis and characterization of UO2(II) and Th(IV) binuclear complexes with o-vanillylidene anthranilic acid

Two new solid binuclear complexes of the compositions [(UO₂)₂(HL)₃]NO₃, and [Th₂(HL)₃(NO₃)₂](NO₃)₃ (H₂L=o-vanillylidene anthranilic acid) have been synthesized and characterized by elemental analyses, DTA-TG, IR spectra, UV spectra and molar conductance. Possible structures of the two complexes have been proposed.     

Dinuclear Schiff-base copper(II) complexes with various bridging groups

Three new centrosymmetric dinuclear copper(II) complexes, [Cu₂Cl₂(L¹)₂] (1), [Cu₂(μ _1,3-NCS)₂(L²)₂] (2), and [Cu₂(μ _1,1-N₃)₂(L³)₂] (3), where L¹, L², and L³ are the deprotonated forms of the Schiff bases 1-[(2-propylaminoethylimino)methyl]naphthalen-2-ol (HL¹), 1-[(3-methylaminopropylimino)methyl]naphthalen-2-ol (HL²), and 2-[(2-isopropylaminoethylimino)methyl]phenol (HL³), respectively, have been prepared and characterized by elemental analysis, IR spectra, and single-crystal X-ray crystallography. Each Cu is coordinated by the three donors of the Schiff bases and by two bridging groups, forming a square-pyramidal geometry.     

Interaction of uranyl monoaquadiformate with diaza-18-crown-6 in aqueous ethanol

The reaction of {[UO₂(HCOO)₂(H₂O)]} with diaza-18-crown-6 (DA18C6 = C₁₂H₂₆O₄N₂) in aqueous ethanol in the presence of formic acid yields the complexes {[DA18C6H₂]·[UO₂(HCOO)₃]₂} (I), [DA18C6H₂]·[UO₂(HCOO)₄] (II), and [DA18C6H₂]·(HCOO)₂·(H₂O)₂ (III). The complexes are characterized using IR spectroscopy, chemical analysis, and powder X-ray diffraction. From the comparison of the structural and spectral characteristics of [DA18C6H₂]·An₂·(H₂O)_2n (where An = Cl^?,NO ₃ ^? ,HCOO^?,HSO ₄ ^? ; n = 0.1), correlations are derived between the conformation of the [DA18C6H₂]²⁺ units and the conformation-sensitive frequencies. On the basis of these correlations, the conformations of the N⁺CCO and OCCO units were determined in the diazonia cations of compounds I and II and in [DA18C6H₂]·[UO₂(NO₃)₄]; the latter was prepared previously by reacting [UO₂(NO₃)₂(H₂O)₂]·(H₂O)₄ with DA18C6 in ethanol in the presence of nitric acid.     

Unusual ion UO4? formed upon collision induced dissociation of [UO2(NO3)3]?, [UO2(ClO4)3]?, [UO2(CH3COO)3]? ions

The following ions [UO₂(NO₃)₃]⁻, [UO₂(ClO₄)₃]⁻, [UO₂(CH₃COO)₃]⁻ were generated from respective salts (UO₂(NO₃)₂, UO₂(ClO₄)₃, UO₂(CH3COO)2) by laser desorption/ionization (LDI). Collision induced dissociation of the ions has led, among others, to the formation of UO₄ ⁻ ion (m/z 302). The undertaken quantum mechanical calculations showed this ion is most likely to possess square planar geometry as suggested by MP2 results or strongly deformed geometry in between tetrahedral and square planar as indicated by DFT results. Interestingly, geometrical parameters and analysis of electron density suggest it is an U^VI compound, in which oxygen atoms bear unpaired electron and negative charge.     

Coordination polymers of lanthanides incorporating N,N′-ethylenebis(2-hydroxy-1-naphthylideneiminato): syntheses and crystal structures

Reaction of Ln(NO₃)₃?·?6H₂O with H₂napn (H₂napn?=?N,N′-ethylenebis(2-hydroxy-1-naphthylideneiminato)) and KSCN produces seven new coordination polymers, [La(H₂napn)(SCN)(C₂H₅OH)₂(NO₃)₂] _n (1), [La(H₂napn)₂(SCN)(NO₃)₂] _n (2), and [Ln(H₂napn)_1.5(NO₃)₃] _n [Ln?=?La(3), Sm(4), Eu(5), Dy(6), Er(7)]. Crystal structure analysis reveals that H₂napn functions as a bridging ligand, forming a 1-D chain polymer (1) and 2-D open-frameworks (2–7) with lanthanides. Each metal center of 1–7 is nine-coordinate. Lanthanide contraction is observed in 3–7.     

Syntheses and structures of cobalt(II), nickel(II), and copper(II) complexes with N,N,N′,N′-tetraalkylpyridine-2,6-dicarboxamides (O-daap) containing nitrate as the counter ion

Reactions of M(NO₃)₂?·?xH₂O [M?=?Co(II), Ni(II), and Cu(II)] with N,N,N′,N′-tetraalkylpyridine-2,6-dicarboxamides(O-daap) in CH₃CN yield [Co(O-dmap)(NO₃)₂] (1), [Co(O-deap)(NO₃)₂] (2), [Co(O-dpap)(NO₃)₂] (3), [Ni(O-dmap)(H₂O)₃](NO₃)₂] (4), [Ni(O-deap)(H₂O)₂(NO₃)](NO₃)] (5), [Cu(O-deap)(NO₃)₂] (6), and [Cu(O-dpap)(NO₃)₂] (7). X-ray crystal structures of 1, 2, 4, 5, and 7 reveal that O-daap ligands coordinate tridentate to each metal, O–N–O, with nitrate playing a vital role in molecular and crystal structures of all the complexes. The coordination geometry in the two Co(II) complexes, 1 and 2, is approximately pentagonal bipyramidal with nitrate bonded in a slightly unsymmetrical bidentate chelating mode. [Ni(dmap)(H₂O)₃](NO₃)₂ (4) and [Ni(deap)(H₂O)₂(NO₃)](NO₃) (5) exhibit octahedral geometry, the former containing uncoordinated nitrate while the latter has one nitrate coordinated unidentate and the other nitrate outside the coordination sphere. The Cu(II) in [Cu(dpap)(NO₃)₂] (7) occupies a distorted square pyramidal geometry and is linked to two unidentate nitrates, although one nitrate is also involved in a weak interaction with the metal through its other oxygen. IR spectra and other physical studies are consistent with their crystal structural data. O-dmap?=?N,N,N′,N′-tetramethylpyridine-2,6-dicarboxamides; O-deap?=?N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamides; and O-dpap?=?N,N,N′,N′-tetraisopropylpyridine-2,6-dicarboxamides.     

Vibrational spectroscopic studies of uranyl complexes in aqueous and non-aqueous solutions

Vibrational spectra have been obtained for aqueous solution of uranyl-perchlorates, -fluorides, -chlorides, -acetates and -sulphates over a range of solution composition with added anions. We have prepared [Buⁿ₄N][UO₂Cl₄], [Me₄N][UO₂Cl₄], [Prⁿ₄N][[UO₂(NO₃)₃], [Buⁿ₄N][UO₂(NO₃)₃], with the expectation that the large cation would give a better approximation to vibrational frequencies of the free anion and would allow measurements in non-coordinating solvents. As the perchlorate is not coordinated to [UO₂]²⁺ in aqueous solution the expected structure is a solvated cation [UO₂(OH₂)₅]²⁺ with characteristic infrared 962.5, 253 and 160 cm⁻¹ and Raman 874 and 198 cm⁻¹ bands. The formation of weak, solvated [UO₂X]⁺ complexes (X=F, Cl) has been established with frequencies at 908, 827, 254, 380 cm⁻¹ and 956, 871, 254 and 222 cm⁻¹ for [UO₂F]⁺ and [UO₂Cl]⁺, respectively. Bidentate NO₃ coordination has been established for solid and dissolved (in CH₂Cl₂) [R₄N][UO₂(NO₃)₃] (R=Prⁿ, Buⁿ). Aqueous solutions of UO₂(NO₃)₂ and Cs[UO₂(NO₃)₃] show no clear evidence that bidentate or monodentate nitrate is present. Both unidentate and bidentate linkage of acetate-uranyl were established for acetate complexes in aqueous solutions. For the uranyl sulphate system, monodentate sulphate coordination is the major mode at low SO₄:U ratios, and even at a ratio of 3:1 there is very little free sulphate.     

Phase diagrams for the [Th(NO3)4(TBP)2]-decane-[UO2(NO3)2(TBP)2] liquid ternary system

We report a phase diagram (on the mole fraction scale) for the [Th(NO₃)₄(TBP)₂]-decane-[UO₂(NO₃)₂(TBP)₂](1-2-3) ternary liquid system, where TBP stands for tributyl phosphate, at T = 298.15 K. This system is characterized by a homogeneous solution field and a two-liquid field (immiscibility field); one phase (phase I) is enriched in [Th(NO₃)₄(TBP)₂] and [UO₂(NO₃)₂(TBP)₂], and the other (phase II) is enriched in decane. Molecular interaction parameters and excess Gibbs energies G ^ex were calculated for the binary systems and the ternary liquid system along the binodal curve proceeding from miscibility in the [Th(NO₃)₄(TBP)₂]-decane system and the ternary system and using equations of the NTRL model. For the ternary system, G ^ex > 0. G ^ex decreases in the following order of pairs of liquids: (1, 2) > (2, 3) > (1, 3).     

Design,synthesis and structure of uranyl coordination polymers from 2-D layer to 3-D network structure

Solvothermal reaction of uranyl acetate and succinic acid in DMF resulted in formation of three uranyl coordination polymers, [(UO₂)₄(μ₂-OH)₇(OH)₆]·2(H₂O)·(H₃O)·4NH₂(CH₃)₂ (1), [(UO₂)(μ₂-OH)(OH)₃]·2NH₂(CH₃)₂] (2), and [(DMF)₂(UO₂)(μ₂-OH)₄(UO₂))] (3). The products were characterized by elemental analysis, IR spectroscopy, X-ray single crystal, and powder diffraction. Structural analysis shows that 1 is a layer, 2 and 3 are 3-D network structures.     

Crystal and molecular structure of (NH4)2[UO2(NO3)4] and [(NH4)(18C6)]2[UO2(NO3)4]

Single crystals of diammonium tetranitratouranylate (NH₄)₂[UO₂(NO₃)₄] (I) and a new diammonium tetranitratouranylate complex with 18-crown-6 [(NH₄)(18C6)]₂[UO₂(NO₃)₄] (II) have been synthesized by the reaction of diaquadinitratouranyl tetrahydrate with ammonium nitrate in a nitric acid solution and the reaction of the same reagents with 18C6 in an ethanol solution, respectively. The X-ray diffraction analysis of compounds I and II has been performed. Crystals of compounds I and II are monoclinic, Z = 2, space group P2₁/n, a = 6.4075(5) ?, b = 7.7851(7) ?, c = 12.4461(12) ?, β = 101.239(1)°, V = 608. 94(9) ?³ for compound I and a = 10.542(9) ?, b = 8.590(8) ?, c = 22.5019(19) ?, β = 101.632(1)°, V = 2058.3(3) ?³ for compound II. The [UO₂(NO₃)₄]²⁻ complex anion in compounds I and II contains two monodentate and two bidentate cyclic nitrato groups, and the coordination number of uranyl is 6. The 18C6 molecule in the structure of compound II has the classic crown conformation and combined with the ammonium ion by three hydrogen bonds. Compounds I and II formed by electrostatic attraction forces between counterions are stabilized by (NH₄⁺)NH...O(NO₃⁻) interionic hydrogen bonds.     

Ten complexes constructed by two reduced Schiff base tetraazamacrocycle ligands: syntheses,structures, magnetic and luminescent properties

Ten new complexes, [Cu₂(L¹)(NO₃)₂]·2H₂O (1), [Cu₄(L¹)₂]·4ClO₄·H₂O (2), [Cu₂(L¹)(H₂O)₂]·(adipate) (3), [Cu₆(L¹)₂(m-bdc)₄]·2DMF·5H₂O (4), [Cu₂(L¹)(Hbtc)]·5H₂O (5), [Cu₂(L¹)(H₂O)₂]·(ntc)·3H₂O (6), [Co₂(L²)]·[Co(MeOH)₄(H₂O)₂] (7), [Co₃(L²)(EtOH)(H₂O)] (8), [Ni₆(L²)₂(H₂O)₄]·H₂O (9) and [Zn₄(L²)(OAc)₂]·0.5H₂O (10), have been synthesized. 1 displays a [Cu₂(L¹)(NO₃)₂] monomolecular structure. 2 shows a supramolecular chain including [Cu₂L¹]²⁺. In 3, two Cu(II) ions are connected by L¹ to form a [Cu₂(L¹)(H₂O)₂]²⁺ cation. In 4, the m-bdc anions bridge Cu(II) ions and L¹ anions to form a layer. Both 5 and 6 display 3-D supramolecular structures. 7 consists of both [Co₂L²]^2? and [Co(MeOH)₄(H₂O)₂]²⁺ units. 8 and 9 show infinite chain structures. In 10, Zn(II) dimers are linked by L² to generate a 3-D framework. The magnetic properties for 4 and 8 and the luminescent property for 10 have been studied.     

Low‐Dimensional Structural Units in Amine‐Templated Uranyl Oxoselenates(VI): Synthesis and Crystal Structures of [C3H12N2][(UO2)(SeO4)2(H2O)2](H2O), [C5H16N2]2[(UO2)(SeO4)2(H2O)](NO3)2, [C4H12N][(UO2)(SeO4)(NO3)], and [C4H14N2][(UO2)(SeO4)2(H2O)]

The crystals of four amine‐templated uranyl oxoselenates(VI), [C₃H₁₂N₂][(UO₂)(SeO₄)₂(H₂O)₂](H₂O) ( 1 ), [C₅H₁₆N₂]₂[(UO₂)(SeO₄)₂(H₂O)](NO₃)₂ ( 2 ), [C₄H₁₂N][(UO₂)(SeO₄)(NO₃)] ( 3 ), and [C₄H₁₄N₂][(UO₂)(SeO₄)₂(H₂O)] ( 4 ) were prepared by evaporation from aqueous solution of uranyl nitrate, selenic acid and the respective amine. The crystal structures of all four compounds have been solved by direct methods from X‐ray diffraction data. The structure of 1 (triclinic, , a = 7.5611(16), b = 7.7650(17), c = 12.925(3) Å, α = 94.605(18), β = 94.405(17), γ = 96.470(17)°, V = 748.8(3) ų, R₁ = 0.029 for 2769 unique observed reflections) is based upon 0D‐units of the composition [(UO₂)₂(SeO₄)₄(H₂O)₄]^4?. These discrete units are composed from two pentagonal [UO₇]^8? bipyramids linked via [SeO₄]^2? tetrahedra and are unknown in structural chemistry of uranium so far. The structure of 2 (monoclinic, C2/c, a = 28.916(5), b = 8.0836(10), c = 11.9856(16) Å, β = 110.909(11)°, V = 2617.1(6) ų, R₁ = 0.035 for 2578 unique observed reflections) contains [(UO₂)(SeO₄)₂(H₂O)]^2? chains of corner‐sharing pentagonal [UO₇]^8? bipyramids and [SeO₄]^2? tetrahedra. The chains run parallel to the c axis and are arranged into layers parallel to (100). In the structure of 3 (monoclinic, C2/m, a = 21.244(5), b = 7.1092(11), c = 8.6581(18) Å, β = 97.693(17)°, V = 1295.8(4) ų, R₁ = 0.027 for 1386 unique observed reflections), pentagonal [UO₇]^8? bipyramids share corners with three [SeO₄]^2? tetrahedra each and an edge with a [NO₃]^? anion to form [(UO₂)(SeO₄)(NO₃)]^? chains parallel to the b axis. In the structure of 4 (triclinic, , a = 6.853(2), b = 10.537(3), c = 10.574(3) Å, α = 99.62(3), β = 94.45(3), γ = 100.52(3)°, V = 735.6(4) ų, R₁ = 0.045 for 2713 unique observed reflections), one symmetrically independent pentagonal [UO₇]^8? bipyramid shares corners with four [SeO₄]^2? tetrahedra to form the [(UO₂)(SeO₄)₂(H₂O)]^2? chains parallel to the a axis. A comparison to related uranyl compounds is given.