Insertion of trivalent uranium in macrocyclic crown-ethers: EXAFS and X-ray structural analyses

Déjean, Alain; Charpin, P.; Folcher, G.; Rigny, Paul; Navaza, A.; Tsoucaris, G.

doi:10.1016/s0277-5387(00)80788-3

Cited by 31 publications

(13 citation statements)

References 20 publications

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“…Complex (I) thus comprises two U atoms in completely different environments bridged by an asymmetric oxo group. The environment around U1 is comparable with that of the U III ion in the bis(tetrahydroborate) dicyclohexyl-18-crown-6 complex (Dejean et al, 1987), one of the BH 4 groups being replaced by O7. The coordination of metal atom U2 is reminiscent of that observed in [U(BH 4 ) 4 OR 2 ] (R = methyl or ethyl; Rietz et al, 1978).…”

Section: Commentmentioning

confidence: 92%

“…The ®rst to be reported were uranium(IV) complexes, in which the coordination sphere was completed by three chloride groups (de Villardi et al, 1978;Bombieri et al, 1978). A bis(tetrahydroborate) uranium(III) complex with dicyclohexyl-18-crown-6 has also been described (Dejean et al, 1987), as well as several uranyl complexes (Thue Â ry et al, 1995, and references therein). In the course of our studies of the reactions of tetramethylethylene with U(BH 4 ) 4 (Villiers & Ephritikhine, 1995), we obtained the title compound, (I), which appeared to be a dinuclear molecular complex of unprecedented geometry.…”

Section: Commentmentioning

confidence: 99%

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(18-Crown-6)-μ-oxo-hexakis(tetrahydroborato)diuranium(IV): an unprecedented asymmetric dinuclear complex

2006

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In the title compound, (1,4,7,10,13,16-hexaoxacyclooctadecane-1kappa6O)-mu-oxo-1:2kappa2O:O-hexakis(tetrahydroborato)-1kappa3H;2kappa2H;2kappa2H;2kappa3H;2kappa3H;2kappa3H-diuranium(IV), [U2(BH4)6O(C12H24O6)], one of the U atoms (U1), located at the centre of the crown ether moiety, is bound to the six ether O atoms, and also to a tridentate tetrahydroborate group and a mu-oxo atom in axial positions. The other U atom (U2) is bound to the same oxo group and to five tetrahydroborate moieties, three of them tridentate and the other two bidentate. The two metal centres are bridged by the mu-oxo atom in an asymmetric fashion, thus giving the species (18-crown-6)(kappa3-BH4)U=(mu-O)-U(kappa3-BH4)3(kappa2-BH4)2, in which the U1=O and U2-O bond lengths to the mu-O atom [1.979 (5) and 2.187 (5) angstroms, respectively] are indicative of the presence of positive and negative partial charges on U1 and U2, respectively.

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Section: Commentmentioning

confidence: 92%

Section: Commentmentioning

confidence: 99%

(18-Crown-6)-μ-oxo-hexakis(tetrahydroborato)diuranium(IV): an unprecedented asymmetric dinuclear complex

2006

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“…See http://www.rsc.org/suppdata/cp/b3/b317003a/ R E S E A R C H P A P E R PCCP www.rsc.org/pccp of the uranyl ion occurs in acetonitrile. 23 Exact complex concentrations were obtained via the stability constants of the complexes. 24a,24c In the case of dicyclohexano-18-crown-6, we used a racemic mixture of the anti-cis and syn-cis isomers of cis-dicyclohexano-18-crown-6.…”

Section: Methodsmentioning

confidence: 99%

Spectroscopic properties of uranyl crown ether complexes in non-aqueous solvents

Servaes

Houwer

Görller‐Walrand

et al. 2004

Phys. Chem. Chem. Phys.

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The spectroscopic properties of the complexes of uranyl with oxacrowns, azacrowns, thiacrowns of different ring size, polyethyleneglycols , and [2.2.1] and [2.2.2] cryptands were studied in acetonitrile and propylene carbonate solutions by absorption and luminescence spectroscopy. Depending on the ligand, marked differences in the fine structure of the spectra were observed. The crown ethers with six oxygen atoms (18-crown-6, dicyclohexano-18-crown-6, benzo-18-crown-6, dibenzo-18-crown-6 and [2,4]-dibenzo-18crown-6) form inclusion complexes with the uranyl ion in the central cavity. In the case of 18-crown-6 and dibenzo-18-crown-6, a complex with a high coordination symmetry is formed. Outer-sphere complexes are formed with the crown ethers with small ring size (12-crown-4 and 15-crown-5) and with PEG-200. Only minor changes in the spectra were observed when changing the ligand. The spectra of the large crown ethers ([3,4]-dibenzo-21crown-7, dibenzo-24-crown-8 and dibenzo-30-crown-10), together with those of PEG-300 and PEG-400 show that these ligands coordinate in the equatorial plane to the uranyl ion. In the presence of competing inorganic ligands like chloride and nitrate ions, the crown ether is replaced in the first coordination sphere. Azacrowns and cryptands coordinate externally to the uranyl ion, and the corresponding spectra do not show fine structure. In the case of the thiacrowns, no coordination of the ligand to the uranyl ion was observed.

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“…Of particular interest has been the inclusion of the uranyl ion in macrocycles; however, the majority of structural studies concern complexes in which the crown ligand is linked to the uranyl ion via hydrogen bonds (Rogers, Bond, Hippie, Rollins & Henry, 1991;Gutberlet, Dreissig, Luger, Bechthold, Maung & Knochel, 1989) and few structural studies show a direct uranyl-crown coordination (Navaza, Villain & Charpin, 1984;Dejean, Charpin, Folcher, Rigny, Navaza & Tsoucaris, 1987;Deshayes, Keller, Lance, Navaza, Nierlich & Vigner, 1993). The probability of the uranyl complexing in the crown cavity is increased by a judicious choice of the solvent-anion pair, which has to be poorly coordinating with respect to the uranyl.…”

Section: Commentmentioning

confidence: 99%

Inclusion complex between uranyl and an azacrown; structure of [UO2(18-azacrown-6)]2+.2CF3SO3−

Nierlich¹,

Sabattié²,

Keller³

et al. 1994

Acta Crystallogr C

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Insertion of trivalent uranium in macrocyclic crown-ethers: EXAFS and X-ray structural analyses

Cited by 31 publications

References 20 publications

(18-Crown-6)-μ-oxo-hexakis(tetrahydroborato)diuranium(IV): an unprecedented asymmetric dinuclear complex

(18-Crown-6)-μ-oxo-hexakis(tetrahydroborato)diuranium(IV): an unprecedented asymmetric dinuclear complex

Spectroscopic properties of uranyl crown ether complexes in non-aqueous solvents

Inclusion complex between uranyl and an azacrown; structure of [UO2(18-azacrown-6)]2+.2CF3SO3−

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