Hilda Wullens

Preparation of ternary Bi-La and Bi-Pr oxides from polyaminocarboxylate complexes.

Ternary bismuth–lanthanum and bismuth–praseodymium oxides are prepared by thermal decomposition of precursor complexes derived from solutions containing polyaminocarboxylate ligands: H4edta, H5dtpa, H4egta and H6ttha. The thermal decomposition of these solid precursors is investigated by TGA. The resulting Bi–La and Bi–Pr oxides are characterized by XRD, XPS analysis and SBET measurements. XRD reveals the formation of Bi2−xLnxO3 solid solutions based on the fluorite-like δ-Bi2O3 structure when Bi:Ln=0.5 and Bi:Ln=1, while a rhombohedral phase appears when Bi:Ln=2. Surface contamination by hydroxyl and carbonate species increases with the Ln content. Specific surface areas as high as 30 m2/g are obtained for the Ln-rich compositions. These results are compared with those obtained by the ceramic and citrate methods.

A new dodecanuclear bismuth polyaminocarboxylate complex with 2-hydroxy-1,3-diaminopropanetetraacetic acid

A new dodecanuclear Bi(III) complex with 2-hydroxy-1,3-diaminopropanetetraacetic acid (H(5)hpdta) corresponding to the stoichiometry Bi-12(Bi(12)hdtpa)(4)(Hhdtpa)(6) was obtained from Bi(III) oxocarbonate and the starting polyaminocarboxylic acid. The crystal structure revealed the presence of two asymmetric parts containing six Bi atoms, each of which displays a ninefold coordination. The involvement of the central hydroxo group in Bi coordination is assumed to be responsible for the peculiarities of this unique structure: the simultaneous involvement of one of the ligands in the coordination of two Bi atoms, the presence of Bi atoms bridged by either one, or three oxygens at the same time, the presence of bridging bidentate (mu(2):eta(1):eta(2)) carboxylates, and direct coordination of Bi(III) to water molecules

Synthesis, characterization and crystal structures of bismuth(III) complexes with triethylenetetraaminehexaacetic acid and trans-cyclohexane-1,2-diaminetetraacetic acid

Two new water-soluble bismuth(III) complexes with polyaminocarboxylate ligands have been prepared, characterized by IR spectroscopy and crystal-structure analysis. The complex with triethylenetetraaminehexaacetic acid (H(6)ttha) has the stoichiometry Bi(H(3)ttha). 3H(2)O 1. It crystallizes in the space group P2/c with two independent 1/2 (H(3)ttha . Bi) units in which the cations are located on the crystallographic two-fold axis. It is the first example of a polyaminocarboxylate complex of Bi-III displaying a co-ordination number of ten, through four nitrogen atoms and six oxygens belonging to the acetates. The ligand is wrapped round the cation in a bicapped square-antiprismatic geometry. In the complex with trans-cyclohexane-1,2-diaminetetraacetic acid (H(4)cydta), Bi(Hcydta). 5H(2)O 2, the co-ordination number is eight with a square-antiprismatic geometry around the Bi. For each Bi atom two of the co-ordinated oxygen atoms belong to neighbouring molecules; these bridging oxygen atoms are different in the two subunits and connect the complexed entities in a polymeric network.

Crystal structure of di(hexaphenyldiphosphazenium) ethanolpentachlorobismuthate(III), (C36H30P2N)(2)[BiCl5(C2H6O)]

C74H66B1CI5N2OP4, triclinic, PI (No. 2), a = 13.751(3) Â, b = 16.190(4) Â, c = 17.100(4) Â, a = 75.06(2)°,/Î = 71.68(2)°, γ = 71.73(2)°, V = 3377.8 Â, Ζ = 2, R&(F) = 0.041, wRretfF) = 0.083, Τ= 293 Κ. Source of material The compound has been obtained as crystals while attempting to isolate bismuth complexes with the polyaminocarboxylic acid ligand H4egta (ethyleneglycol-bis-(2-aminoethyl)tetraacetic acid). Bismuth oxocarbonate (0.667 g ; 2.617 mmol) was added to * Correspondence author (e-mail: tinant@chim.ucl.ac.be) a boiling solution of Hjegta (1.01 g ; 2.653 mmol). After reaction, hexaphenyldiphosphazenium chloride ((PPN)Cl) (1.501 g; 2.615 mmol) was added to the reaction mixture. A precipitate appeared on cooling. Addition of ethanol caused the precipitate to redissolve. Prismatic crystals appeared in the solution after several weeks. Elemental analysis: calculated (%): C, 58.88; H, 4.41; N, 1.86; P, 8.21; CI, 11.74; found: C, 58.82; H, 4.12; N, 2.11; P, 8.35; a , 13.53. Experimental details The hydrogen atom of the OH of ethanol was not located. All the other H atoms were calculated, and a common isotropic temperature factor was refined (Uiso = 0.062(2) Â). There are two positions for the ethanol molecule, which was disordered These positions were included in the refinement, and the site occupation factor converged to 0.57(2) for position A and 0.43 for position B. Restraints were applied on C—C and C—O bond lengths of the ethanol. Discussion We report the first example of a crystal structure of a monomelic pentachloro 6-cooidinated Βί(ΠΓ) complex in which the sixth coordination site is occupied by the oxygen atom of an ethanol molecule. Bi halogeno complexes are generally studied with the aim of obtaining new data on the stereochemical activity of the electron lone pair of Βϊ(ΙΠ). Bismuth halides usually adopt dimeric edgeshared bioctahedral structures (BÍ2Xs(L)2) with L being a two electron donor ligand. Compounds containing the [B12CI10] anion belong to this category. The structures of several of them were investigated in relationship with the therapeutical use of Bi(m) salts as anti-ulcer drugs when combined with antibiotics like ciprofloxacin, the latter giving compounds containing either the dimeric [BÍ2CI10] unit [1 ] or monomelic hexachlorobismuthate ions, [BiClé] [2]. In the complex reported here the structure is monomeric. The upper figure shows the coordination of the metal. The packing of the [BiCl5(C2H60)] anions and hexaphenyldiphosphazenium cations is presented in the lower figure. The configuration of the 6-coordinated Βί(ΙΠ) complex is a distorted octahedron. The Bi—CI bond lengths range from 2.501 Â to 2.753 Â (with a mean value of2.658 Â) while the Bi—O bond is longer (the average of the distance over the two positions of the ethanol oxygen is 2.790 Â). If only the major orientation of ethanol is considered, the cis-coordination angles lie between 83.7° and 95.0°, and the mvu-coordination angles range between 172.8° and 174.1 Therefore, we believe that the electron lone pair of Βί(ΙΠ) in this complex is stereochemically active. The Bi—O bond is somewhat longer than in [BÍ2Clg(THF)2] ~ [3] (2.590 Â) but consistent with a coordination bond between bismuth and a non-deprotonated hydroxy 1 group [4]. 386 ( C 3 6 H 3 0 P 2 N ) 2 [ B i C l 5 ( C 2 H 6 O ) ] Table 1. Data collection and handling. Table 2. Continued.

Crystal structure of bis(aminoguanidinium) (hydrogen triethylene-tetramine-hexaacetato)praseodymate(III) hydrate, C18H25N4O12Pr center dot 2CH(7)N(4) center dot 3.7H(2)O

C20H46.40N12O15.70Pr, triclinic, P (1) over bar (No. 2), a = 10.329(2) Angstrom, b = 10.725(3) Angstrom, c = 15.635(4) Angstrom, alpha = 107.05(2)degrees, beta = 90.43(2)degrees, gamma = 93.35(2)degrees, V = 1652.5 Angstrom(3), Z = 2, R-gt(F) = 0.050, wR(ref)(F-2) = 0.149, T = 293 K.