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Pierre Thuéry

Publications and source records attributed to Pierre Thuéry.

At least 19 recordsLinked to original sources
PubMed2006

Complexation of quaternary ammonium ions by tetraester derivatives of [3.1.3.1]homooxacalixarene in mobile and in fixed conformation.

In the tetraalkylation of p-tert-butyl[3.1.3.1]homooxacalixarene with BrCH2CO2R and K2CO3 in acetone, the initially formed cone conformer is converted into the more stable 1,4-alternate conformer when R = Me or Et, but not when R = i-Pr or t-Bu. In the case of R = i-Pr, derivatives in fixed 1,4-alternate conformation and in partial cone conformation were also isolated. Compounds in fixed cone conformation are good ligands for tetramethylammonium, acetylcholine, and N-methylpyridinium salts in CDCl3, but the partial cone isomer proved to be somewhat better and even the 1,4-alternate conformer turned out to be active. The possible involvement of the ester functions as additional binding sites is discussed; moreover, an insight into the energetics of the complexation and conformational isomerization processes is given.

Alkylation↗
PubMed2006

Lanthanide and uranium complexes with an SPS-based pincer ligand.

Reactions of Ln(BH4)3(THF)n and [Li(Et2O)]SPS(Me)], the lithium salt of an anionic SPS pincer ligand composed of a central hypervalent lambda4-phosphinine ring bearing two ortho-positioned diphenylphosphine sulfide sidearms, led to the monosubstituted compounds [Ln(BH4)2(SPS(Me))(THF)2] [Ln = Ce (1), Nd (2)], while the homoleptic complexes [Ln(SPS(Me))3] [Ln = Ce (3), Nd (4)] were obtained by treatment of LnX3 (X = I, BH4) with [K(Et2O)][SPS(Me)]. The [UX2(SPS(Me))2] complexes [X = Cl (5), BH4 (6)] were isolated from reactions of UX4 and the lithium or potassium salt of the [SPS(Me)]- anion. The X-ray crystal structures of 1.1.5THF, 2.1.5THF, 3.2THF.2Et2O, and 5.4py reveal that the flexible tridentate [SPS(Me)]- anion is bound to the metal as a tertiary phosphine with electronic delocalization within the unsaturated parts of the ligand.

Journal Article↗
PubMed2006

CsF-promoted acetyl dance at the narrow rim of p-tert-butyl[3.1.3.1]homooxacalixarene.

In the acetylation of an oxygenated calix[4]arene homologue in the presence of CsF as a base, relaxation of the reaction system to the equilibrium composition takes place through several intra- and intermolecular steps that can be easily controlled to obtain the various acetyl derivatives. The effect of different bases is also discussed.

Journal Article↗
PubMed2006

U(SMes*)n, (n = 3, 4) and Ln(SMes*)3 (Ln = La, Ce, Pr, Nd): lanthanide(III)/actinide(III) differentiation in agostic interactions and an unprecedented eta3 ligation mode of the arylthiolate ligand, from X-ray diffraction and DFT analysis.

Reaction of U(NEt(2))(4) with HS-2,4,6-(t)Bu(3)C(6)H(2) (HSMes) gave U(SMes)(3)(NEt(2))(py) (1), whereas similar treatment of U[N(SiMe(3))SiMe(2)CH(2)][N(SiMe(3))(2)](2) afforded U(SMes)[N(SiMe(3))(2)](3) (2) and U(SMes)(3)[N(SiMe(3))(2)]. The first neutral homoleptic uranium(IV) thiolate to have been crystallographically characterized, U(SMes)(4) (4), was isolated from the reaction of U(BH(4))(4) and KSMes. The first homoleptic thiolate complex of uranium(III), U(SMes)(3) (5), was synthesized by protonolysis of U[N(SiMe(3))(2)](3) with HSMes in cyclohexane. The crystal structure of 5 exhibits the novel eta(3) ligation mode for the arylthiolate ligand. Comparison of the crystal structure of 5 with those of the isomorphous lanthanide congeners Ln(SMes)(3) (Ln = La, Ce, Pr, and Nd) indicates that the U-S, U-C(ipso)(), and U-C(ortho)() bond lengths are shorter than the corresponding ones in the 4f-element analogues, when taking into account the variation in the ionic radii of the metals. The distance between the uranium and the carbon atoms involved in the U...H-C epsilon agostic interaction of each thiolate ligand is shorter, by approximately 0.05 A, than that expected from a purely ionic bonding model. The lanthanide(III)/actinide(III) differentiation was analyzed by density functional theory (DFT). The nature of the M-S bond is shown to be ionic strongly polarized at the sulfur for M = U and iono-covalent (i.e. strongly ionic with low orbital interaction), for M = Ln. The strength of the U...H-C epsilon agostic interaction is proposed to be controlled by the maximization of the interaction between U(+) and S(-) under steric constraints. The eta(3) ligation mode of the arylthiolate ligand is also obtained from DFT.

Journal Article↗
PubMed2006

Easy access to stable pentavalent uranyl complexes.

Reaction of UO2I2(THF)3 with 1 molar equivalent of KC5R5 (R = H, Me) in pyridine led to the uranyl(V) compound {[UO2(Py)5][KI2(Py)2]}(infinity), which is an infinite 1D polymer in its crystalline form; the UO2X(THF)n (X = I, OSO2CF3) complexes were obtained by reduction of their U(VI) parents with TlC5H5 or KC5R5 in THF.

Journal Article↗
PubMed2006

(Borohydrido)(18-crown-6)potassium and (borohydrido)(dibenzo-18-crown-6)(tetrahydrofuran)potassium.

In the two compounds (borohydrido)(1,4,7,10,13,16-hexaoxacyclooctadecane-kappa(6)O)potassium, [K(BH(4))(C(12)H(24)O(6))], (I), and (borohydrido)(1,4,7,10,13,16-hexaoxa-2,3:11,12-dibenzocyclooctadeca-2,11-diene-kappa(6)O)(tetrahydrofuran)potassium, [K(BH(4))(C(4)H(8)O)(C(20)H(24)O(6))], (II), the K atom is bound to the six O atoms of the crown ether and to a tridentate borohydride group, with further coordination to a tetrahydrofuran molecule in (II). The alkali metal ion environment is thus distorted hexagonal-pyramidal in (I) and bipyramidal in (II).

Journal Article↗
PubMed2006

Synthesis and crystal structure of uranium(IV) complexes with calix[n]arenes (n = 4, 6 and 8): mononuclear, polynuclear and 1D polymeric species.

Reactions of UCl4 with calix[n]arenes (n = 4, 6) in THF gave the mononuclear [UCl2(calix[4]arene - 2H)(THF)2].2THF (.2THF) and the bis-dinuclear [U2Cl2(calix[6]arene - 6H)(THF)3]2.6THF (.6THF) complexes, respectively, while the mono-, di- and trinuclear compounds [Hpy]2[UCl3(calix[4]arene - 3H)].py (.py), [Hpy](4)[U2Cl6(calix[6]arene - 6H)].3py (.3py), [Hpy]3[U2Cl5(calix[6]arene - 6H)(py)].py (.py) and [Hpy]6[U3Cl11(calix[8]arene - 7H)].3py (.3py) were obtained by treatment of UCl4 with calix[n]arenes (n = 4, 6, 8) in pyridine. The sodium salt of calix[8]arene reacted with UCl4 to give the pentanuclear complex [U{U2Cl3(calix[8]arene - 7H)(py)5}2].8py (.8py). Reaction of U(acac)4 (acac = MeCOCHCOMe) with calix[4]arene in pyridine afforded the mononuclear complex [U(acac)2(calix[4]arene - 2H)].4py (.4py) and its treatment with the sodium salt of calix[8]arene led to the formation of the 1D polymer [U2(acac)6(calix[8]arene - 6H)(py)4Na4]n. The sandwich complex [Hpy]2[U(calix[4]arene - 3H)2][OTf].4py (.4py) was obtained by treatment of U(OTf)4 (OTf = OSO2CF3) with calix[4]arene in pyridine. All the complexes have been characterized by X-ray diffraction analysis.

Journal Article↗
PubMed2006

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

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.

Journal Article↗
PubMed2006

Magnetic anisotropy of two trinuclear and tetranuclear Cr(III)Ni(II) cyanide-bridged complexes with spin ground states S = 4 and 5.

The trinuclear and the tetranuclear complexes [[iPrtacnCr(CN)3]2[Ni(cyclam)]](NO3)2.5H2O 1 (cyclam = 1,4,8,11-tetraazacyclotetradecane, iPrtacn = 1,4,7-tris-isopropyl-1,4,7-triazacyclononane) and [[iPrtacnCr(CN)3Ni(Me2bpy)2]2](ClO4)4.2CH3CN 2 (Me2bpy = 4,4-dimethyl-2,2-bipyridine) were synthesized by reacting (iPrtacn)Cr(CN)3 with [Ni(cyclam)](NO3)2 and [Ni(Me2bpy)2(H2O)2](ClO4)2, respectively. The crystallographic structure of the two compounds was solved. The molecular structure of complex 1 consists of a linear Cr-Ni-Cr arrangement with a central Ni(cyclam) unit surrounded by two Cr(iPrtacn)(CN)3 molecules through bridging cyanides. Each peripheral chromium complex has two pending CN ligands. Complex 2 has a square planar arrangement with the metal ions occupying the vertices of the square. Each Cr(iPrtacn)(CN)3 molecule has two bridging and one non-bridging cyanide ligands. The magnetic properties of the two complexes were investigated by susceptibility vs. temperature and magnetization vs. field studies. As expected from the orthogonality of the magnetic orbitals between Cr(III) (t2g3) and Ni(II) (e(g)2) metal ions, a ferromagnetic exchange interaction occurs leading to a spin ground states S = 4 and 5 for 1 and 2, respectively. The magnetization vs. field studies at T = 2, 3 and 4 K showed the presence of a magnetic anisotropy within the ground spin states leading to zero-field splitting parameters obtained by fitting the data D4 = 0.36 cm(-1) and D5 = 0.19 cm(-1) (the indices 4 and 5 refer to the ground states of complexes 1 and 2, respectively). In order to quantify precisely the magnitude of the axial (D) and the rhombic (E) anisotropy parameters, High-field high frequency electron paramagnetic resonance (HF-HFEPR) experiments were carried out. The best simulation of the experimental spectra (at 190 and 285 GHz) gave the following parameters for 1: D4 = 0.312 cm(-1), E4/D4 = 0.01, g4x = 2.003, g4y = 2.017 and g4z = 2.015. For complex 2 two sets of parameters could be extracted from the EPR spectra because a doubling of the resonances were observed and assigned to the presence of complexes with slightly different structures at low temperature: D5 = 0.154 (0.13) cm(-1), E5/D5 = 0.31 (0.31) cm(-1), g4x = 2.04 (2.05), g4y = 2.05 (2.05) and g4z = 2.03 (2.02). The knowledge of the magnetic anisotropy parameters of the mononuclear Cr(iPrtacn)(CN)3, Ni(cyclam)(NCS)2 and Ni(bpy)2(NCS)2 complexes by combining HF-HFEPR studies and calculation using a software based on the angular overlap model (AOM) allowed to determine the orientation of the local D tensors of the metal ions forming the polynuclear complexes. We, subsequently, show that the anisotropy parameters of the polynuclear complexes computed from the projection of the local tensors are in excellent agreement with the experimental ones extracted from the EPR experiments.

Journal Article↗
PubMed2006

Synthesis, crystal structure and reactivity of uranium(IV) complexes with p-tert-butylcalix[4]arene ligands.

Reactions of UCl4 with 25,27-dimethoxy-5,11,17,23-tetra-tert-butylcalix[4]arene (H2Me2calix) in THF or pyridine at 80 degrees C gave [UCl2(Me2calix)L2] [L = THF (1) or pyridine (2)]. Similar treatment of U(acac)(4) (acac = MeCOCHCOMe) with H2Me2calix in THF or pyridine afforded [U(acac)2(Me2calix)] (3). The bis-calixarene compound [U(Me2calix)(H2calix)] (4) was obtained by reaction of U(OTf)4 or U(OTf)3 with H2Me2calix in pyridine at 110 degrees C. Treatment of UCl4 with H2Me2calix in pyridine at 110 degrees C gave [Mepy][UCl2(Hcalix)(py)2] (5) resulting from demethylation and acid cleavage of the methoxy groups of the calixarene ligand of 2. Adventitious traces of air were responsible for the formation of [Hpy][Mepy]4[{UCl(calix)}3(mu3-O)][UCl6] (6) during the reaction of UCl4 and H2Me2calix, and of [{U(Me2calix)(mu3-O)LiCl(THF)}2] (7) during the reaction of 2 with tBuLi. The X-ray crystal structures of 1.2THF, 2.2py, 3.0.25L (L = THF and py), 4.2py, 5, 6.3py and 7.THF have been determined.

Journal Article↗
PubMed2006

An unprecedented type of linear metallocene with an f-element.

The dication [(C5Me5)2U(NCMe)5]2+ was obtained by dissolving (C5Me5)2UI2 in acetonitrile or by treating (C5Me5)2UMe2 with HNEt3BPh4 in acetonitrile. The crystal structure revealed that the cyclopentadienyl rings are parallel and equidistant to the plane defined by the metal center and nitrogen atoms of the five MeCN ligands. Fifty years after the discovery of ferrocene, this compound represents a unique example of linear metallocene with auxiliary ligands in the equatorial girdle; it is also the first linear sandwich complex of an f-element.

Journal Article↗
PubMed2006

Methyl ether derivatives of p-tert-Butyl[3.1.3.1]homooxacalixarene. Formation, structure, and complexes with quaternary ammonium ions.

[structure: see text] The whole set (five compounds) of partially O-methylated products of p-tert-butyl[3.1.3.1]homooxacalixarene, currently named p-tert-butyltetrahomodioxacalix[4]arene, have been prepared. Their structure has been investigated in solution through NMR techniques and in the solid state by single-crystal X-ray diffraction. A systematic investigation, extended to the parent tetraphenol and to the tetramethyl ether derivative, has been carried out on the complexation of tetramethylammonium, acetylcholine, N-methylpyridinium, and tetraethylammonium picrate in CDCl3. The observed trends in the binding and in the selectivity of the strictly related hosts could be analyzed on the basis of the varying importance of intramolecular hydrogen bonding and its effects on the conformation of the free and of the complexed ligands. On increasing the number of methyl ether functions, the cone conformation appears to be relatively less stable but deeper, so small organic cations can be more effectively encircled.

Journal Article↗
PubMed2006

Uranyl ion complexation by citric and tricarballylic acids: hydrothermal synthesis and structure of two- and three-dimensional uranium-organic frameworks.

The first crystal structure of uranyl citrate is reported, as well as that of uranyl sodium tricarballylate; both compounds are polymeric, with all acid groups coordinated, but they differ strongly in their coordination modes; the resulting assembly architecture is either three-dimensional with [(UO2)2(Hcit)2]2- metallacycle subunits with citrate or two-dimensional with tricarballylate.

Journal Article↗
PubMed2006

Synthesis, structure, and magnetic behavior of a series of trinuclear Schiff base complexes of 5f (UIV, ThIV) and 3d (CuII, ZnII) ions.

The reaction of [M(H(2)L(i))] (M = Cu, Zn) and U(acac)(4) in refluxing pyridine produced the trinuclear complexes [[ML(i)(py)(x)](2)U] [L(i) = N,N'-bis(3-hydroxysalicylidene)-R, R = 1,2-ethanediamine (i = 1), 2-methyl-1,2-propanediamine (i = 2), 1,2-cyclohexanediamine (i = 3), 1,2-phenylenediamine (i = 4), 4,5-dimethyl-1,2-phenylenediamine (i = 5), 1,3-propanediamine (i = 6), 2,2-dimethyl-1,3-propanediamine (i = 7), 2-amino-benzylamine (i = 8), or 1,4-butanediamine (i = 9); x = 0 or 1]. The crystal structures show that the central U(IV) ion adopts the same dodecahedral configuration in all of these compounds, while the Cu(II) ion coordination geometry and the Cu...U distance vary with the length of the diimino chain of the Schiff base ligand L(i). These geometrical parameters have a major influence on the magnetic properties of the complexes. For the smallest Cu...U distances (i = 1-5), the Cu-U coupling is antiferromagnetic and weak antiferromagnetic interactions are present between the Cu(II) ions, while for the largest Cu...U distances (i = 6-9), the Cu-U coupling is ferromagnetic and no interaction is observed between the Cu(II) ions. The magnetic behavior of the [[CuL(i)](2)Th] compounds (i = 1, 2), in which the Th(IV) ion is diamagnetic, confirms the presence of weak intramolecular antiferromagnetic coupling between the Cu(II) ions.

Journal Article↗
PubMed2006

Uranium(IV) complexes of calix[n]arenes (n = 4, 6 and 8).

Reaction of UCl4 with calix[n]arenes (n = 4, 6 and 8) in THF or pyridine gave the mononuclear [UCl2(calix[4]arene--2H)(THF)2], bis-binuclear [U2Cl2(calix[6]arene--6H)(THF)3]2 and trinuclear [Hpy]6[U3Cl11(calix[8]arene--7H)] complexes, respectively, which are the first U(IV) complexes of O-unsubstituted calixarenes.

Journal Article↗