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Bruno Donnadieu

Publications and source records attributed to Bruno Donnadieu.

49 records · Page 3Linked to original sources
PubMed2003

Synthesis and crystal structure of unprecedented phosphine adducts of d(1)-aryl imido-vanadium(IV) complexes.

The reaction of the imido precursor [V(NAr)Cl(2)](n)() (1) (Ar = 2,6-i-Pr(2)C(6)H(3)) with 3 equiv of PMe(2)Ph yields the monomeric complex [V(=NAr)Cl(2)(PMe(2)Ph)(2)] (2). Reacting 1 with 1.5 equiv of dmpe or 1 equiv of dppm affords the dimeric complexes [V(=NAr)Cl(2)(dmpe)](2)(mu-P,P'-dmpe) (3) and [V(=NAr)Cl(2)(dppm)](2) (4), respectively. Complexes 2-4 have been fully characterized by spectroscopic methods, magnetism studies, and X-ray crystallography.

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PubMed2002

Synthesis and structure of a series of new d(1)-Aryl imido-vanadium(IV) complexes stabilized by n-donor ligands.

A family of new coordination vanadium(IV) compounds supported by a terminal or bridged aryl imido ligand are reported. Reaction of V(NMe(2))(4) with anilines ArNH(2), where Ar = 2,6-i-Pr(2)-C(6)H(3), 2,6-Me(2)-C(6)H(3), Ph, 2,6-Cl(2)-C(6)H(3), and C(6)F(5), afforded the diamagnetic imido-bridged complexes [V(NAr)(NMe(2))(2)](2) (1a-e). Chlorination of 1a-e with trimethylchlorosilane afforded complexes 2a-e formulated as [V(=NAr)Cl(2)(NHMe(2))(x)()](n)(). One-pot reaction of V(NMe(2))(4) with ArNH(2) in the presence of an excess of trimethylchlorosilane gave the five-coordinate compound [V(=NAr)Cl(2)(NHMe(2))(2)] (3a-e). Reaction of 3a-e with pyridine, bipyridine (bipy), or N,N,N',N'-tetramethylethylenediamine (tmeda) gave respectively the six-coordinate tris- or bis(pyridine) adducts [V(=NAr)Cl(2)(Py)(3)] (4a-e) or [V(=NAr)Cl(2)(Py)(2)(NHMe(2))] (5a), bipyridine complexes [V(=NAr)Cl(2)(bipy)(NHMe(2))] (5a-e) and [V(=NAr)Cl(2)(bipy)(Py)] (9a), and tmeda adduct [V(=NAr)Cl(2)(tmeda)(NHMe(2))] (10a). Moreover, five-coordinate complexes free of NHMe(2) ligands, such as [V(=NAr)Cl(2)(Py)(2)] (5a), [V(=NAr)Cl(2)(bipy)] (8a), and [V(=NAr)Cl(2)(tmeda)] (11a), were directly prepared starting from precursors 2a-e. All compounds were totally characterized by spectroscopic methods (IR, (1)H NMR for diamagnetic complexes, and EPR for paramagnetic complexes), elemental analysis, magnetism, and single-crystal X-ray diffraction studies for 1b, 3a, 3d, 4b, 4d, 7c, 10a, and 11a.

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PubMed2002

Reactivity of vanadocene with a nitrile -C identical to N bond activated by a tris(fluorophenyl)borane as Lewis acid: formation of borane adducts of vanada(IV)azirine complexes--EPR evidence for an intramolecular C-F...V interaction.

Reaction of vanadocene [V(Cp)2] with "activated" nitrile R1CN.L (L: Lewis acid), obtained by the reaction of borane adducts (L = BR3; R = C6F5, 2,6-F2C6H3, 3,4,5-F3C6H2) with nitriles (CH3CN, F3CC6H4CN), yields the borane adduct of vanada(IV)azirine complexes [V(Cp)2(eta 2-R1C = N.L)]. EPR studies of a fluid solution were conducted on these complexes. A doublet of octets due to the coupling of one unpaired electron of the vanadium with the 51V (I = 7/2) nucleus and to an additional hyperfine coupling to the ortho-F atom borne by the phenyl ring of the borane was elucidated by means of the different Lewis acids used in this work. This EPR behaviour gives evidence for the presence of a C-F...V interaction in a fluid solution with L = B(C6F5)3 and B(2,6-F2C6H3)3. In contrast, the expected eight line EPR pattern is observed with L = B(3,4,5-F3C6H2)3, in which no ortho-F atoms are present in the phenyl ring. A model can be drawn to take into account this flexibility and V...F distances between V and ortho-F atoms are in the expected range for such an interaction.

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PubMed2002

[N(CH3)4]2[Mn(H2O)]3[Mo(CN)7](2).2H2O: a new high Tc cyano-bridged ferrimagnet based on the [MoIII(CN)7]4- building block and induced by counterion exchange.

The title compound was synthesized by slow diffusion of aqueous solutions containing K4[Mo(CN)7].2H2O, [Mn(H2O)6](NO3)2, and [N(CH3)4]Cl. The compound crystallized in monoclinic space group C2/c, a = 25.8546(14), b = 12.3906(7), c = 13.5382(7) A, beta = 116.4170 (10) degrees, Z = 4, R = 0.0353, wR2 = 0.0456. The MoIII site is surrounded by six -C-N-Mn linkages and one terminal cyano group in a distorted capped-prism fashion. There are two pentahedral MnII sites in the structure, both with four -N-C-Mo linkages and one water molecule. The anisotropic three-dimensional structure consists of connected corrugated gridlike sheet layers parallel to the bc plane. Tetramethylammonium counterions ([N(CH3)4]+) located between these layers seem to induce their distortion. The three-dimensional organization may also be viewed as interconnected octagonal channels propagated along the c axis. The void space of these channels is occupied by coordinated and crystalized water molecules. Temperature and field dependence of the magnetization in both the dc and ac modes have been measured on polycrystalline sample. These investigations have revealed that the compound ordered ferrimagnetically at Tc = 86 K, with a small hysteresis effect. These findings have been compared to those reported previously for three- and two-dimensional materials of the same family.

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PubMed2002

sigma-Borane and dihydroborate complexes of ruthenium.

Room temperature reaction of the bis(dihydrogen) complex RuH(2)(H(2))(2)(PCy(3))(2) (1) with excess pinacol borane (HBpin) generates the novel complex RuH[(mu-H)(2)Bpin](sigma-HBpin)(PCy(3))(2) (2) by loss of dihydrogen. Complex 2 was characterized spectroscopically and by X-ray crystallography. It contains two pinacolborane moieties coordinated in a different fashion, one as a dihydroborate (B-H distances : 1.58(3) and 1.47(3) A) and the other as a sigma-borane (B-H distance: 1.35(3) A). In addition, reaction of 1 with one equiv of HBpin yields total conversion to a new complex tentatively formulated as RuH[(mu-H)(2)Bpin](H(2))(PCy(3))(2) (3) on the basis of NMR data. In the presence of excess HBpin, 3 is converted to 2. Furthermore, under an atmosphere of dihydrogen, a C(7)D(8) solution of 2 rapidly converts to 3 and finally regenerates 1 over a much longer period. Thus, complex 3 is an intermediate in the formation of 2 from 1. In these processes the borane is eliminated as HBpin later hydrolyzed to BpinOBpin. Selective hydroboration of ethylene (3 bar) into C(2)H(5)Bpin is achieved using 1 or 2 as catalyst precursors in toluene, whereas in THF, competitive formation of the vinylborane C(2)H(3)Bpin (56% under 20 bar of C(2)H(4)) can be favored.

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PubMed2002

Stable formally zerovalent and diamagnetic monovalent niobium and tantalum complexes based on diazadiene ligands.

This paper describes the efficient synthesis and full characterization of rare formally zerovalent and diamagnetic monovalent pseudooctahedral niobium and tantalum complexes. The reaction of NbCl(4)(thf)(2) with 4 equiv of Na and 3.5 equiv of iPr(2)-dad (1,4-diisopropyl-1,4-diaza-1,3-diene) yields Nb(iPr(2)-dad)(3) in 52% yield. Ta(iPr(2)-dad)(3) is also obtained in 33% yield from 5 equiv of Na/naphthalene and 3.5 equiv of iPr(2)-dad. Oxidation of these complexes with AgBPh(4) yields the diamagnetic complexes [M(iPr(2)-dad)(3)][BPh(4)] (M = Nb, Ta). X-ray and spectroscopic data indicate that the unpaired electron density is localized on the ligands. DFT calculations reveal that, in the prevailing D(3) symmetry, a very strong splitting of t(2g) metal-based orbitals occurs, leading to the diamagnetism of the 16e M(iPr(2)-dad)(3)(+). This strong splitting allows a M-N nonbonding, ligand-based orbital to accommodate additional electrons, as a result of which the formally zerovalent complexes, M(iPr(2)-dad)(3), are in fact correctly formulated as M(+)iPr(2)-dad (-), that is, (16e + 1e).

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PubMed1998

Preparation of the New Bis(phenanthroline) Ligand "Clip-Phen" and Evaluation of the Nuclease Activity of the Corresponding Copper Complex.

The best nuclease activities of 1,10-phenanthroline-copper complexes have been observed for a chelate/metal stoichiometry of 2/1. To favor this stoichiometry, the "Clip-Phen" ligand was synthesized with two 1,10-phenanthroline units linked via their C2-carbons by a short flexible arm. An exogenous amine function was present to allow future vectorization of this new chelating ligand. X-ray analysis of monocrystals of Clip-Phen confirmed its structure. An EPR study of (Clip-Phen)CuCl(2) showed that the cupric ion was pentacoordinated with a water molecule as the possible fifth ligand. The Cu(I/II) redox couple was found to be near 85 mV vs SCE, close to the redox couple of (Phen)(2)CuCl(2). A comparison of the nuclease activity of copper complexes of Clip-Phen and 1,10-phenanthroline indicated that (Clip-Phen)Cu was the more active.

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PubMed1997

Reactivity of the Acyclic Diazadioxa Redox Active Ligand [(C(5)H(5))Fe(C(5)H(4)CH(2)N(CH(3))(CH(2))(2)OCH(2)-)](2): NMR, Electrochemical, and Mössbauer Studies. Crystal Structure of Its Copper Complex.

Several novel diazadioxa ferrocenyl derivatives have been prepared along with their previously unknown electroactive precursor [(C(5)H(5))Fe(C(5)H(4)CH(2)N(CH(3))(CH(2))(2)OCH(2)-)](2) (2). Di-N,N'-protonated and -methylated species [2(H)(2)][X](2) (3a-c) (X = CF(3)SO(3), BF(4), PF(6)) and [2(Me)(2)][CF(3)SO(3)](2) (5), and N-H-N monoprotonated species [2H][X] (4a-c) have been isolated in high yield. The efficient syntheses of compounds [2Na][PF(6)] (6), [2Cu][CF(3)SO(3)] (7), [2Ag][CF(3)SO(3)] (8), and [2MCl(2)] (M = Zn, Hg) (9, 10) are reported. The crystal structure of complex 7 has been determined by X-ray analysis at 180 K. Crystal data: monoclinic P2(1)/c, with a = 11.511(2) Å, b = 19.613(2) Å, c = 14.493(2) Å, beta = 88.32(2) degrees, V = 3273.2(1) Å(3), Z = 4; R = 0.034, R(w) = 0.039 for 3379 observations and 407 variable parameters. The copper(I) atom, bound to the two O and two N atoms of the ferrocenyl ligand, is in a very distorted tetrahedral geometry with a large N(1)CuN(2) angle (163.1(2) degrees ). In cyclic voltammetry, 4a-c undergo two quasi-reversible (Fe(II)/Fe(III)) redox processes at 0.1 V s(-)(1). Electrochemical studies of 3a-c, 5, 7, and 8 show that diprotonation and dialkylation of 2 or complexation of a Cu (Ag) salt induces an anodic shift ranging from 240 to 110 mV. Chemical oxidation of 2 (5 equiv of Ag(I)) produces the cation [2(H)(2)](4+) (11). The quantitative two-step electrochemical oxidation of 2 at controlled potential in CH(3)CN also leads to 11: an ECE mechanism, in which the diprotonated species plays a key role, is proposed. Mössbauer data of 2, 3c, 6, 7, 8, and 11 are also presented.

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PubMed1997

Transition-Metal Derivatives of a Functionalized Cyclopentadienyl Ligand. 15. Synthesis and Structures of Amino Cyclopentadienyl Derivatives of Rhodium(I) and Rhodium(III) Including Water-Soluble Compounds.

The synthesis of monometallic rhodium(III) and rhodium(I) derivatives of dialkylamino-functionalized cyclopentadienyl using the corresponding cyclopentadiene as starting material is facilitated by the presence of the basic amino group. This procedure affords the chloro salts of the substituted rhodicinium cation [(eta(5)-C(5)H(4)(CH(2))(2)NMe(2)H)(2)Rh(III)](3+) ([1][Cl](3)) from the reaction of the [2-(dimethylamino)ethyl]cyclopentadiene with Na(3)Rh(III)Cl(6). 12H(2)O. Similarly the cationic half-sandwich complexes [(eta(5)-C(5)H(4)(CH(2))(n)()NMe(2)H)Rh(I)(cod)](+) (n = 2, [2][Cl], n = 3, [5][Cl]) are obtained from the reaction of the corresponding dialkylamino cyclopentadiene with [RhCl(cod)](2). These types of cationic complexes, 1, 2, and 5, bear pendant ammonium groups. The most classical procedure, starting from the lithium or more efficiently from the sodium cyclopentadienide salt, was used to synthesize neutral complexes [(eta(5)-C(5)H(4)(CH(2))(n)()NMe(2))Rh(I)(cod)] (n = 2, 3; n = 3, 4). The structure of the chloride bis(hexafluorophosphate) salt, [(eta(5)-C(5)H(4)(CH(2))(2)NMe(2)H)(2)Rh(III)](3+)(Cl(-))(PF(6)(-))(2), ([1][Cl][PF(6)](2)) was solved in the triclinic space group P&onemacr; with one molecule in the unit cell, the dimensions of which are a = 6.617(2) Å, b= 7.436(2) Å, c = 13.965(3) Å, alpha = 76.39(2) degrees, beta = 82.31(3) degrees, gamma = 87.26(2) degrees, and V = 661.8(3) Å(3). The noncentrosymmetric character of this solid is attributed to the chloride ion. The tetrafluoroborate salt [(eta(5)-C(5)H(4)(CH(2))(2)NMe(2)H)Rh(I)(cod)](+)(BF(4)(-)) ([2][BF(4)]) crystallizes in the tetragonal space group P4(2)/n with eight molecules in the unit cell, the dimensions of which are a= 21.183(2) Å, b = 21.179(3) Å, c= 8.324(2) Å, and V = 3734(1) Å(3). Least squares refinement leads to values for the conventional R index of [1][Cl][PF(6)](2) (0.0484 for 2191 reflections used) and of [2][BF(4)] (0.0525 for 1083 reflections used); in both cases I > 3sigma(I). As expected, compounds like [2][Cl](3,) [1][Cl][PF(6)](2), [2][Cl], [2][BF(4)], [5][Cl], and [5][BF(4)] are soluble in water.

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PubMed1996

Metal Complexes of Dithiolate Ligands: 5,6-Dihydro-1,4-dithiin-2,3-dithiolato (dddt(2-)), 5,7-Dihydro-1,4,6-trithiin-2,3-dithiolato (dtdt(2-)), and 2-Thioxo-1,3-dithiole-4,5-dithiolato (dmit(2-)). Synthesis, Electrochemical Studies, Crystal and Electronic Structures, and Conducting Properties.

New precursors to potentially conductive noninteger oxidation state (NIOS) compounds based on metal complexes [ML(2)](n)()(-) [M = Ni, Pd, Pt; L = 5,6-dihydro-1,4-dithiin-2,3-dithiolato (dddt(2)(-)), 5,7-dihydro-1,4,6-trithiin-2,3-dithiolato (dtdt(2)(-)), and 2-thioxo-1,3-dithiole-4,5-dithiolato (dmit(2)(-)); n = 2, 1, 0] have been investigated. Complexes of the series (NR(4))[ML(2)] (R = Me, Et, Bu; L = dddt(2)(-), dtdt(2)(-)) have been isolated and characterized, and the crystal structure of (NBu(4))[Pt(dtdt)(2)] (1) has been determined {1 = C(24)H(44)NPtS(10), a = 12.064(2) Å, b = 17.201(3) Å, c = 16.878(2) Å, beta = 102.22(2) degrees, V = 3423(1) Å(3), monoclinic, P2(1)/n, Z = 4}. Oxidation of these complexes affords the corresponding neutral species [ML(2)](0). Another series of general formula (cation)(n)()[M(dmit)(2)] [cation = PPN(+), BTP(+), and (SMe(y)()Et(3)(-)(y)())(+) with y = 0, 1, 2, and 3, n = 2, 1, M = Ni, Pd] has also been studied. All of these (cation)(n)()[M(dmit)(2)] complexes have been isolated and characterized [with the exception of (cation)[Pd(dmit)(2)] for cation = (SMe(y)()Et(3)(-)(y)())(+)]. The crystal structures of (PPN)[Ni(dmit)(2)].(CH(3))(2)CO (2) and (SMeEt(2))[Ni(dmit)(2)] (3) have been determined {2 = C(45)H(36)NNiS(10)P(2)O, a = 12.310(2) Å, b = 13.328(3) Å, c = 15.850(3) Å, alpha = 108.19(3) degrees, beta = 96.64(2) degrees, gamma = 99.67(2) degrees, V = 2373(1) Å(3), triclinic, P&onemacr;, Z = 2; 3 = C(11)H(13)NiS(11), a = 7.171(9) Å, b = 17.802(3) Å, c = 16.251(3) Å, beta = 94.39(4) degrees, V = 2068(2) Å(3), monoclinic, P2(1)/n, Z = 4} NIOS salts derived from the preceding precursors were obtained by electrochemical oxidation. Electrochemical studies of the [M(dddt)(2)] complexes show that they may be used for the preparation of NIOS radical cation salts and [M(dddt)(2)][M'(dmit)(2)](x)() compounds, but not for the preparation of (cation)[M(dddt)(2)](z)() NIOS radical anion salts. The electrochemical oxidation of the [M(dtdt)(2)](-) complexes always yields the neutral [M(dtdt)(2)](0) species. The crystal structure of [Pt(dddt)(2)][Ni(dmit)(2)](2) (4) has been determined and is consistent with the low compaction powder conductivity (5 x 10(-)(5) S cm(-)(1) at room temperature) {4 = C(20)H(8)Ni(2)PtS(28), a = 20.336(4) Å, b = 7.189(2) Å, c = 14.181(2) Å, beta = 97.16(2) degrees, V = 2057(1) Å(3), monoclinic, C2/m, Z = 2}. The crystal structures of the semiconducting NIOS compounds (BTP)[Ni(dmit)(2)](3) (5) and (SMe(3))[Ni(dmit)(2)](2) (6) have been determined {5 = C(43)H(22)PNi(3)S(30), a = 11.927(2) Å, b = 24.919(2) Å, c = 11.829(3) Å, alpha = 93.11(1) degrees, beta = 110.22(1) degrees, gamma = 83.94(1) degrees, V = 3284(1) Å(3), triclinic, P&onemacr;, Z = 2; 6 = C(15)H(9)Ni(2)S(21), a = 7.882(1) Å, b = 11.603(2) Å, c = 17.731(2) Å, alpha = 77.44(1) degrees, beta = 94.39(1) degrees, gamma = 81.27(1) degrees, V = 1563(1) Å(3), triclinic, P&onemacr;, Z = 2}. The parent compound (SEt(3))[Ni(dmit)(2)](z) (unknown stoichiometry) is also a semiconductor with a single-crystal conductivity at room temperature of 10 S cm(-)(1). By contrast, the single-crystal conductivity at room temperature of (SMeEt(2))[Pd(dmit)(2)](2) (7) is rather high (100 S cm(-)(1)). 7 behaves as a pseudometal down to 150 K and undergoes an irreversible metal-insulator transition below this temperature. The crystal structure of 7 has been determined {7 = C(17)H(13)NPd(2)S(21), a = 7.804(4) Å, b = 36.171(18) Å, c = 6.284(2) Å, alpha = 91.68(4) degrees, beta = 112.08(4) degrees, gamma = 88.79(5) degrees, V = 1643(1) Å(3), triclinic, P&onemacr;, Z = 2}. The electronic structure of (SMeEt(2))[Pd(dmit)(2)](2) (7) and the possible origin of the metal-insulator transition at 150 K are discussed on the basis of tight-binding band structure calculations.

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