Structures de complexes d'azoture d'uranyle et de tétraalkylammonium. (I) Triazoture d'uranyle et de tétraéthylammonium. (II) μ3-oxo-azoture d'uranyle et de tétraméthylammonium

Charpin, P.; Lance, M.; Nierlich, Martine; Vigner, D.; Livet, J.; Musikas, C.

doi:10.1107/s0108270186090911

Cited by 23 publications

(6 citation statements)

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“…Structurally characterized uranium azido complexes are rare. With the exception of one mononuclear uranyl complex involving a terminal azide ligand (d(U−N α ) = 2.382 Å, ∠(U−N α −N β ) = 131.67°) and a small number of polynuclear uranyl complexes with terminal and bridged azido ligands, only one other crystallographically characterized U(III) azido species is reported in the literature . The U−N α bond distances in the dinuclear 1,3-μ-azido bridged tris-trimethylsilylcyclopentadienyl uranium anion were found equidistant at 2.40(2) Å with a U−N α −N β angle of 160(1)° (inversion center on N β ).…”

Section: Resultsmentioning

confidence: 99%

Uranium Tris-aryloxide Derivatives Supported by Triazacyclononane: Engendering a Reactive Uranium(III) Center with a Single Pocket for Reactivity

et al. 2003

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The synthesis and spectroscopic characterization of the mononuclear uranium complex [((ArO)(3)tacn)U(III)(NCCH(3))] is reported. The uranium(III) complex reacts with organic azides to yield uranium(IV) azido as well as uranium(V) imido complexes, [((ArO)(3)tacn)U(IV)(N(3))] and [((ArO)(3)tacn)U(V)(NSi(CH(3))(3))]. Single-crystal X-ray diffraction, spectroscopic, and computational studies of this analogous series of uranium tris-aryloxide complexes supported by triazacyclononane are described. The hexadentate, tris-anionic ligand coordinates to the large uranium ion in unprecedented fashion, engendering coordinatively unsaturated and highly reactive uranium centers. The macrocyclic triazacyclononane tris-aryloxide derivative occupies six coordination sites, with the three aryloxide pendant arms forming a trigonal plane at the metal center. DFT quantum mechanic methods were applied to rationalize the reactivity and to elucidate the electronic structure of the newly synthesized compounds. It is shown that the deeply colored uranium(III) and uranium(V) species are stabilized via pi-bonding interaction, involving uranium f-orbitals and the axial acetonitrile and imido ligand, respectively. In contrast, the bonding in the colorless uranium(IV) azido complex is purely ionic in nature. The magnetism of the series of complexes with an [N3O3-N(ax)] core structure and oxidation states +III, +IV, and +V is discussed in context of the electronic structures.

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Section: Resultsmentioning

confidence: 99%

Uranium Tris-aryloxide Derivatives Supported by Triazacyclononane: Engendering a Reactive Uranium(III) Center with a Single Pocket for Reactivity

et al. 2003

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“…In contrast to the large number of transition metal azido complexes, only few uranium azido species have been reported in the literature. 69,70 The molecular structure of the uranium(IV) azide complex in crystals of 9 resembles those of typical metal azido complexes. The linear N 3 2 ligand (/N a -N b -N c = 178.2( 14)u) is bound to the metal ion in a bent fashion with an U-N a -N b angle of 145.9(9)u.…”

Section: Nitrogen Atom Transfer Chemistry Employing Uranium Complexesmentioning

confidence: 95%

Small molecule activation at uranium coordination complexes: control of reactivity via molecular architecture

2006

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Electron-rich uranium coordination complexes display a pronounced reactivity toward small molecules. In this Feature article, the exciting chemistry of trivalent uranium ions coordinated to classic Werner-type ligand environments is reviewed. Three fundamentally important reactions of the [(((R)ArO)3tacn)U]-system are presented that result in alkane coordination, CO/CO2 activation, and nitrogen atom-transfer chemistry.

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“…Molecular structures of uranium compounds containing the uranyl cation UO 2 2+ are the most common class reported for this element . The majority of these compounds have been prepared in protic solutions, and they typically produce aggregates, in which uranyl groups lie parallel to one another in dimers, trimers, tetramers, hexamers, chains, and even channels or helices . Aggregation of the uranyl ions is achieved through bridging ligands that are coordinated in the equatorial plane of UO 2 2+ .…”

Section: Introductionmentioning

confidence: 99%

Steric Control of Substituted Phenoxide Ligands on Product Structures of Uranyl Aryloxide Complexes

et al. 2002

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A series of uranyl aryloxide complexes has been prepared via metathesis reactions between [UO(2)Cl(2)(THF)(2)](2) and di-ortho-substituted phenoxides. Reaction of 4 equiv of KO-2,6-(t)()Bu(2)C(6)H(3) with [UO(2)Cl(2)(THF)(2)](2) in THF produces the dark red uranyl compound, UO(2)(O-2,6-(t)()Bu(2)C(6)H(3))(2)(THF)(2).THF, 1. Single-crystal X-ray diffraction analysis of 1 reveals a monomer in which the uranium is coordinated in a pseudooctahedral fashion by two apical oxo groups, two cis-aryloxides, and two THF ligands. A similar product is prepared by reaction of KO-2,6-Ph(2)C(6)H(3) with [UO(2)Cl(2)(THF)(2)](2) in THF. Single-crystal X-ray diffraction analysis of this compound reveals it to be the trans-monomer UO(2)(O-2,6-Ph(2)C(6)H(3))(2)(THF)(2), 2. Dimeric structures result from the reactions of [UO(2)Cl(2)(THF)(2)](2) with less sterically imposing aryloxide salts, KO-2,6-Cl(2)C(6)H(3) or KO-2,6-Me(2)C(6)H(3). Single-crystal X-ray diffraction analyses of [UO(2)(O-2,6-Cl(2)C(6)H(3))(2)(THF)(2)](2), 3, and [UO(2)Cl(O-2,6-Me(2)C(6)H(3))(THF)(2)](2), 4, reveal similar structures in which each U atom is coordinated by seven ligands in a pseudopentagonal bipyramidal fashion. Coordinated to each uranium are two apical oxo groups and five equatorial ligands (3, one terminal phenoxide, two bridging phenoxides, and two nonadjacent terminal THF ligands; 4, one terminal chloride, two bridging phenoxides, and two nonadjacent terminal THF ligands). Apparently, the phenoxide ligand steric features exert a greater influence on the solid-state structures than the electronic properties of the substituents. Emission spectroscopy has been utilized to investigate the molecularity and electronic structure of these compounds. For example, luminescence spectra taken at liquid nitrogen temperature allow for a determination of the dependence of the molecular aggregation of 3 on the molecular concentration. Electronic and vibrational spectroscopic measurements have been analyzed to examine trends in emission energies and stretching frequencies. However, comparison of the data for compounds 1-4 reveals that the innate electron-donating capacity of phenoxide ligands is only subtly manifest in either the electronic or vibrational energy distributions within these molecules.

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Structures de complexes d'azoture d'uranyle et de tétraalkylammonium. (I) Triazoture d'uranyle et de tétraéthylammonium. (II) μ3-oxo-azoture d'uranyle et de tétraméthylammonium

Cited by 23 publications

References 0 publications

Uranium Tris-aryloxide Derivatives Supported by Triazacyclononane: Engendering a Reactive Uranium(III) Center with a Single Pocket for Reactivity

Uranium Tris-aryloxide Derivatives Supported by Triazacyclononane: Engendering a Reactive Uranium(III) Center with a Single Pocket for Reactivity

Small molecule activation at uranium coordination complexes: control of reactivity via molecular architecture

Steric Control of Substituted Phenoxide Ligands on Product Structures of Uranyl Aryloxide Complexes

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