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The TCNX ligands TCNE and TCNQ reacted in toluene with Cp2V in the presence of B(C6F5)3 to yield, depending on the stoichiometry, the divanadium(III) complexes [(Cp2V)2{(C6F5)3B·(μ4-TCNX)·B(C6F5)3}...

We have developed a new strategy that uses the Krohnke synthesis for the preparation of various substituted phenylpyridines in excellent yields (up to 88 %). Starting with the appropriate commercially available acetophenone, a variety of phenylpyridines substituted by either electron-donating (i.e. methyl, methoxy) or -withdrawing groups (i.e. bromide, nitro) on the phenyl ring are obtained in a two-step synthesis. The corresponding functionalized cyclometalated ruthenium complexes can be prepared with unusually high yields by

Two new ruthenium(II) complexes of formula [Ru(bpy)2(L1)][PF6] and [Ru(bpy)2(L2)][PF6]2 are reported. HL1 is a (nitrophenyl)ethenyl-substituted phenylpyridine ligand, and L2 is the bipyridine analogue of HL1. The X-ray crystal structure of [Ru(bpy)2(L1)][PF6] has been solved, and the compound is found to crystallize in the monoclinic C2/c space group. The electronic spectrum of the cyclometalated derivative [Ru(bpy)2(L1)][PF6] exhibits a low-lying transition that is red-shifted from 454 to 546 nm relative to that of the parent bipyridine-based complex, which reveals an important charge-transfer character. To support this assumption, the nonlinear optical properties were investigated by the hyper-Rayleigh scattering technique and indicate a molecular static hyperpolarizability (β0) equal to 230 × 10–30 cm5 esu–1. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

A new class of Salpen analogues based on phosphorus derivatives where the classical alkylene backbone has been replaced by a N–P–N linkage is described. Such linkage both affords a very good stability in water and an additional (fifth) potentially complexing site. The classical ortho-OH groups have been also replaced by various ortho-substituents, including diphenylphosphino groups. The synthesis of these compounds is easy and their structure can be varied at will at several levels. Several ways of synthesis can be used to combine the various fragments constituting these Salpen analogues. The structure of one of these fragments, an azide, was determined by X-ray crystallography. A preliminary study of the complexation ability of some of these new ligands was carried out with groups 10 (Ni) and 11 (Au) elements. Depending on the type of substituents and the type of metals used, these compounds can act as mono-, or tetra-dentate ligands.

This paper describes an efficient, straightforward synthesis of new hydrotris(pyrazolyl)borate (Tp‘) niobium terminal alkyne complexes and some reactions of these complexes. Reduction of the niobium(IV) complexes Tp‘NbCl3 (Tp‘ = TpMe2 (1), TpMe2,4Cl (1-Cl)) with zinc in the presence of a terminal alkyne HC⋮CR gives good yields (ca. 75%) of the new alkyne complexes Tp‘NbCl2(HC⋮CR) (2-R) (R = H, Ph, C6H4-4-Me, CH2Ph, CF3) and 2-Cl-Ph. The strategy is significant since the previously reported synthesis of Tp‘NbCl2(RC⋮CR‘) was possible only with internal alkynes. NMR data indicate that the four-electron donor alkyne sits in the molecular mirror plane. Restricted alkyne rotation is observed by NMR in solution. The more abundant rotamer has the large substituent located distal to the Tp‘ ligand, thereby alleviating steric interactions. Only this rotamer is observed in the crystal structures of 2-R (R = Ph, C6H4-4-Me, CH2Ph). In the crystal structure of 2-CF3, however, three independent molecules are observed wi...

The bis(dihydrogen) complex RuH2(η2-H2)2(PCy3)2 (1) reacts at room temperature with 1 equiv of either HBpin or HBcat to produce the σ-borane complexes RuH2(η2-HBpin)(η2-H2)(PCy3)2 (2Bpin) and RuH2(η2-HBcat)(η2-H2)(PCy3)2 (2Bcat), respectively, by substitution of one σ-H2 ligand by one σ-B−H. In contrast, when using the 9-BBN reagent, the dihydridoborate complex RuH[(μ-Η)2BBN](η2-H2)(PCy3)2 (2BBN) is formed. The coordination modes of the borane ligands have been ascertained by NMR spectroscopy, X-ray diffraction, and theoretical studies (DFT/B3LYP). The results indicate that the dialkoxyborane ligands (HBpin and HBcat) are not acidic enough to stabilize a “true” symmetrical dihydridoborate coordination mode. They thus lead to σ-borane complexes presenting a small H/BH cis interaction between the boron atom and the adjacent hydride. The σ-H2 ligand in 2Bpin is located by X-ray diffraction at 90 K and found to be perpendicular to the equatorial plane. DFT calculations lead to the optimization of the two dege...

The reaction between [VCp2], BPh3, or BCl3 and the nitrile F3CC6H4C⋮N gives the borane adduct of vanada(IV)azirine complex [VCp2{η2:C,N-F3CC6H4CN·BR3}] (R = Ph (2), Cl (3)). Using B(C6F5)3 and dicy...

Intermolecular alkyne hydroamination with primary amines is catalyzed with group 5 (vanadium and tantalum) transition metal complexes and a new imido-Ti(IV) complex. The reaction is very regioselective. The scope of the reaction was investigated with a variety of alkynes and amines; 1-hexyne and anilines were found to be especially good substrates.

Elusive cationic methyl complexes of niobium, [TpMe2NbMe(L)(MeC⋮CMe)][BArf4] (L = OEt2, PMe2Ph, PEt3), that model the active species in alkene polymerization by group 5 metals have been prepared. The X-ray crystal structure of the diethyl ether adduct has been obtained.

The reaction of [Cp2Ti(CO)2] with borane adducts CF3C6H4CN·B(C6F5)3 and [H2O·B(C6F5)3] has afforded the titanaazirine [Cp2Ti(η2-C,N-F3CC6H4CN)·B(C6F5)3] (1) and the TiIII salt [Cp2Ti][HOB(C6F5)3] (2), respectively. In both cases, a Ti···F interaction between the titanium centre and an ortho-fluorine atom of the tris(perfluorophenyl)borane is observed in the X-ray structure determination. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Transamination reactions of primary amines with group 4 and 5 amido precursors M(NMe(2))(4) have been studied to prepare homo- and heterobimetallic complexes [(Me(2)N)(2)M(1)(μ-NR(1))(μ-NR(2))M(2)(NMe(2))(2)(NHMe(2))(x)] (x = 0, 1) with two identical or distinct bridging imido ligands.

International audience; Compared with the reactivity of o-Ph2P(C6H4–CH2)BH(NiPr2) with [RuH2(η2-H2)2(PCy3)2], the behavior of the phosphinoborane Ph2P(CH2–C6H4)BH(NiPr2) is radically different. No agostic σ-B–H complex could be observed, the reaction leading to the isolation of a new bis-σ borane aryl-ruthenium complex via B–C bond cleavage and Ru–C bond formation. Reactivity studies of this complex with dihydrogen and/or HBArF4 as a proton source enable the formation of a tethered chiral-at-Ru piano-stool cationic complex.

Functionalization of CO2 is a challenging goal and precedents exist for the generation of HCOOH, CO, CH3OH, and CH4 in mild conditions. In this series, CH2O, a very reactive molecule, remains an elementary C1 building block to be observed. Herein we report the direct observation of free formaldehyde from the borane reduction of CO2 catalyzed by a polyhydride ruthenium complex. Guided by mechanistic studies, we disclose the selective trapping of formaldehyde by in situ condensation with a primary amine into the corresponding imine in very mild conditions. Subsequent hydrolysis into amine and a formalin solution demonstrates for the first time that CO2 can be used as a C1 feedstock to produce formaldehyde.

International audience; Four alkaloids named hosieines A–D were isolated from the root and stem of Ormosia hosiei. Their flat structures were established by mass spectrometry and by a combination of NMR experiments. These molecules probably share a common biosynthetic origin with the lupin alkaloids but they differ in the formation of the last ring, being here part of a rare 2-azabicyclo[3.2.1]octane system. Their absolute configuration was determined by X-ray crystallography using CuKα radiation. As has been described for cytisine, they display a remarkable affinity towards neuronal nicotinic acetylcholine α4β2 receptor.

International audience; The reaction of hydroxybenzohydrazide with o-vanillin yields 2-hydroxy-N?-[(2-hydroxy-3-methoxyphenyl)methylidene]benzohydrazide (LH3), a ligand that is able to give mononuclear and tetranuclear copper complexes but also to associate copper and gadolinium ions in a Cu2?Gd2 heterotetranuclear complex. This synthesis is successful if the Gd ions, which are acidic in protic solvents, are introduced in a basic methanol solution of the mononuclear copper complex. In the absence of piperidine, the addition of Gd ions to a methanol solution of the mononuclear copper complex only yields a tetranuclear cubane-type copper complex. This work reports on the first structural characterization of a copper?gadolinium complex involving a benzohydrazide ligand. The resulting complex consists of two Cu?Gd pairs linked by a dihydroxo Gd?Gd bridge, in which the Cu and Gd ions are bridged by a nonsymmetric phenoxo?hydroxo bridge. The magnetostructural correlation between the ferromagnetic coupling constant and the hinge angle observed in symmetrical double-phenoxo Cu?Gd bridges remains valid for dissymmetric Cu?Gd bridges and confirms the preponderance of the structural factor over the nature of the bridge. This tetranuclear complex corresponds to two S = 4 units linked through a dihydroxo bridge introducing a weak antiferromagnetic Gd?Gd interaction and impeding the existence of a S = 8 ground state.

International audience; Three new N-heterocyclic-silazane compounds, 1a-c, were prepared and employed as bidentate ligands to ruthenium, resulting in a series of [Ru(H){(κ-Si,N-(SiMe2-N-heterocycle)}3] complexes (3a-c) featuring the same RuSi3H motif. Detailed structural characterization of the RuSi3H complexes with X-ray diffraction, and in the case of triazabicyclo complex [Ru(H){κ-Si,N-(SiMe2)(C7H12N3)}3] (3a), neutron diffraction, enabled a reliable description of the molecular geometry. The hydride ligand of (3a) is located closer to two of the silicon atoms than it is to the third. Such a geometry differs from that of the previously reported complex [Ru(H){(κ-Si,N-(SiMe2)N(SiMe2H)(C5H4N)}3] (3d), also characterized by neutron diffraction, where the hydride was found to be equidistant from all three silicon atoms. A DFT study revealed that the symmetric and less regular isomers are essentially degenerate. Information on the dynamics and on the Ru***H***Si interactions was gained from multinuclear solid-state (1H wPMLG, 29Si CP MAS, and 2D 1H-29Si dipolar HETCOR experiments) and solution NMR studies. The corresponding intermediate complexes, [Ru{κ-Si,N-(SiMe2-N-heterocycle)}(η4-C8H12)(η3-C8H11)] (2a-c), involving a single silazane ligand were isolated and characterized by multinuclear NMR and X-ray diffraction. Protonation of the RuSi3H complexes was also studied. Reaction of 3a with NH4PF6 gave rise to [Ru(H)(η2-H −SiMe2)κ-N-(C7H12N3){κ-Si,N-(SiMe2)(C7H12N3)}2]+[PF6]−(4aPF6) which was isolated and characterized by NMR spectroscopy, X-ray crystallography, and DFT studies. The nature of the Si-H interactions in this silazane series was analyzed in detail.

International audience; The first part of this study is devoted to the search for improved and highly efficient synthetic procedures for the preparation of rhodium carbonyl precursors, and the second part to the production of acetyl derivatives. Microwave heating of a methanol solution of RhCl3·xH2O for 10 min under 5–10 bar CO produces the complex [H]+[RhCl2(CO)2]–, which is quantitatively converted into the dimeric complex [Rh2(μ-Cl)2(CO)4] (1) by rapid solvent evaporation under a stream of CO. The treatment of 1 with NaI or AgOAc under a CO atmosphere gives [Rh2(μ-I)2(CO)4] (2) and [Rh2(μ-OAc)2(CO)4] (3), respectively. The complex cis-[PPN][RhI2(CO)2] (4) is prepared in high yield by the reaction of RhI3 with N,N-dimethylformamide (DMF) at 160 °C under CO followed by metathesis of the [NH2Me2]+ cation with [bis(triphenylphosphoranylidene)ammonium]chloride ([PPN]Cl). The analogue cis-[PPN][Rh(OAc)2(CO)2] (5) is obtained by reaction of 4 with AgOAc. Complex 4 reacts with neat CH3I to afford quantitatively the dimeric rhodium(III) complex [PPN]2[Rh2(μ-I)2I4(COMe)2(CO)2] (7). The cleavage of the iodo bridging ligands in 7 occurs readily with CO, pyridine or 1,2-dimethylimidazole to give [PPN][RhI3(COMe)(CO)2] (8), [PPN][RhI3(COMe)(CO)(Py)] (9) and [PPN][RhI3(COMe)(CO)(1,2-MeIm)] (10), respectively, whereas the reactions with the chelating 2-acetylpyridine and methyl-2-picolinate ligands give the neutral [Rh(COMe)I2(CO)(κ2-2-acetylpyridine)] (11) and [Rh(COMe)I2(CO)(κ2-methyl-2-picolinate)] (12) complexes, respectively. The X-ray crystal structures of 4, 7 (centrosymmetric isomer), 8, 11 and 12 have been solved. The reductive elimination from 7 and 8 in the presence of various carboxylato sources to provide acid anhydrides is described.

International audience; The straightforward synthesis of tethered η5-oxocyclohexadienyl Ru(II) complexes is presented. Pioneering results in catalysis show that these original half-sandwich Ru(II) complexes allow the effective isomerization of allylic alcohols under mild conditions without further additives; η5-oxocyclohexadienyl ruthenium complexes may be considered as a new class of catalysts. © 2014 American Chemical Society.

International audience; The copper complex of a polydentate non-symmetrical Schiff base ligand [LCu]2, prepared by template synthesis, has been reacted with the series of lanthanide ions. This complex used as a ligand possesses two functions (phenol and oxime) able to coordinate the Ln ions and, according to the Ln ion, three types of complexes are obtained. From La to Eu, trinuclear [(LCu)2Ln(NO3)3] complexes with a double phenoxo-oximato bridge were isolated. From Gd to Ho, the complexes [(LCu)2Ln(NO3)3(H2O)] are still trinuclear, with a supplementary water molecule linked to the Ln ion but the CuII and LnIII ions are only bridged by the oximato (N-O) pair, the phenoxo oxygen atom being hydrogen-bridged to the Ln-coordinated water molecule. Then, with heavier Ln ions, dinuclear [(LCu)Ln(NO3)3(H2O)2] complexes are characterized. The magnetic study demonstrates that the oximato bridge is responsible for the antiferromagnetic character of the Cu-Gd interaction, with JCuGd = -0.63 cm-1 in [(LCu)2Gd(NO3)3(H2O)], in contrast to the ferromagnetic Cu-Gd interaction induced by the single oxygen atom phenoxo bridge.

Partial substitution of P by As, leading to the solid solution CsH 2 (PO 4 ) 1− x (AsO 4 ) x , with x =0.28 (abbreviated as CDAP) has been shown. The structural characteristics of the crystals were analyzed by means of X-ray diffraction, which revealed that the new title compound is nearly isomorphous with the monoclinic phase of CsH 2 PO 4 (CDP). The structure was solved from 796 independent reflections with R 1 =0.0292 and Rw 2 =0.0702, refined with 59 parameters. The following results have been obtained: space group P2 1 , a =4.9250(4) A, b =6.4370(3) A, c =7.9280(6) A, β =107.316(3)°, V =239.94(3) A 3 , Z =2 and ρ cal =3.349 g cm −3 . The hydrogen bonds are clearly distinguished in the electron density maps which display distributions corresponding to order of protons. The shorter bond (2.452(4) A), links the phosphate–arsenate groups into chains running along the b -axis and the longer bond (2.531(3) A), crosslinks the chains to form (001) layers. The Raman and infrared spectra of CDAP recorded at room temperature in the frequency ranges 15–1200 cm −1 and 400–4000 cm −1 , respectively, confirm the presence of PO 3− 4 and AsO 3− 4 groups in the crystal. Differential scanning calorimetry traces show three phase transitions at 333, 449 and 490 K in this material, which are characterized by X-ray powder diffraction at high temperature.

This work describes the synthesis of three key intermediates of Noyori-type catalytic systems that are active precatalysts for the transfer hydrogenation of acetophenone. Isolation of the cationic chloro(dihydrogen) complex [RuCl(H(2))(H(2)NNPP)(PCy(3))][BArf(4)] provides a facile synthetic route to the corresponding cationic and neutral hydrido complexes, and the series highlights the links between hydride/dihydrogen and amine/amido ligands in neutral and cationic species.

The reaction of tert-butylborane with the bis(dihydrogen) complex RuH2(η2-H2)2(PCy3)2 leads to the corresponding bis σ-borane complex which is the first example of a monoalkylborane ruthenium bis σ-complex. An alternative route involves the reaction of RuHCl(η2-H2)(PCy3)2 with lithium tert-butylborohydride.

The new charge transfer salt, BET-TTF[Ni(dmit)2]2, was obtained using the electrodeposition method. Thin layers of this new salt were grown on (001)-oriented silicon wafers as anode. The stoichiometry of the new salt was evaluated by infrared and Raman spectroscopy and the unit cell parameters of its structure were determined by powder X-ray diffraction. It was found that, by using different current density during the electrodeposition, layers of different morphologies can be obtained, but the stoichiometry of the formed salt remains the same.

The phosphinosilane compound PPh2CH2OSiMe2H is potentially a bifunctional P∼Si−H ligand. By treatment with the RuII precursor RuH2(H2)2(PCy3)2, the complex Ru(PPh2CH2OSiMe2H)3 (2), resulting from the coordination of three ligands and the displacement of two PCy3 and two dihydrogen ligands, was formed. The different bonding modes for each of the three bifunctional P∼Si−H ligands are discussed on the basis of multinuclear NMR, X-ray diffraction, and density functional theory studies. One ligand acts as a monodentate phosphine ligand with a pendant Si−H group, whereas the two others act as bidentate ligands with different Si−H bond activations. Indeed, an intermediate structure between two arrested forms 2a and 2b can be proposed: a dihydrido(disilyl)ruthenium(IV) species (form 2a) resulting from two Si−H oxidative additions or a hydrido(silyl)ruthenium(II) species (form 2b) presenting an agostic Si−H bond and only one oxidative addition.

Reaction of malononitrile, NCCH2CN, with V(C6H6)2 in toluene in the presence of 2 equiv of B(C6F5)3 afforded the vanadium(I) complex [V(C6H5Me)2][(F5C6)3B·NCCHCN·B-(C6F5)3], in which deprotonation of the malononitrile ligand and arene exchange at the vanadium center have occurred. In the absence of malononitrile, a redox reaction was observed between V(C6H6)2 and the water adduct H2O·B(C6F5)3, which gave the vanadium(I) complex [V(C6H6)2][(F5C6)3BOB(C6F5)2].

The title molecule, C14H12O4S8, has a U-shaped conformation and its crystal structure feaures short intermolecular S...S contacts.

The reaction of Cp2V with B(C6F5)3 in the presence of water leads to the hydride complex [Cp2V(μ-H)B(C6F5)3] (1) and the hydroxide complex [Cp2V(μ-OH)B(C6F5)3] (2), both of which have been characterized by X-ray structure determinations. Both complexes are derived from the ionization of water in the presence of B(C6F5)3.

In the cation of the title complex, [Ru(C31H32N3P2)(C10H8N2)2](PF6)(Br)2·2CH2Cl2·H2O, the ruthenium ion is coordinated in a distorted octahedral geometry by two 2,2′-bipyridine (bpy) ligands and a chelating cationicN-diphenylphosphino-1,3,4,6,7,8-hexahydro-2-pyrimido[1,2-a]pyrimidine [(PPh2)2-hpp] ligand. The tricationic charge of the complex is balanced by two bromide and one hexafluoridophosphate counter-anions. The compound crystallized with two molecules of dichloromethane (one of which is equally disordered about a Cl atom) and a water molecule. In the crystal, one of the Br anions bridges two water moleculesviaO—H...Br hydrogen bonds, forming a centrosymmetric diamond-shapedR42(8) motif. The cation and anions and the solvent molecules are linkedviaC—H...F, C—H...Br, C—H...Cl and C—H...O hydrogen bonds, forming a three-dimensional network.

1477-9226; The reaction of 3-pentafluoroethyl-4,5,6,7-tetrafluoro-1-H-indazole [3-(C2F5)IndF4]H with Ag2O or [Cu(CH3CN)4]BF4 leads to the formation of two different types of complexes: a trinuclear {[3-(C2F5)IndF4]Ag}3 complex (1) in the case of silver, and an unprecedented type of pentanuclear complex [Et3NH]{Cu5[3-(C2F5)IndF4]6} (2) in the case of copper. When crystallised from Et2O, 1 appears as a dimer with d10-d10 interactions. When crystallized from toluene, 1 affords the [(toluene)(1)(toluene)] adduct, testifying to its strong [small pi]-acid properties. The formation and the aggregation pattern of 1 and 2 can be traced to the extended aromaticity and high electron withdrawing properties of the perfluorinated [3-(C2F5)IndF4]- indazolate.

International audience; Treating the imidotitanium dimer [Ti(μ-NAr)(NMe2)2]2 (Ar = 2,6-iPr2C6H3) with excess Me3SiCl affords the hexanuclear complex [{Ti(═NAr)Cl2}6(Cl)]−[Q]+. The self-assembled hexameric cage arrangement encapsulates a chloride ion guest that provides evidence of new host–guest chemistry in this area, while the cationic part is composed of mixtures of the Q+ cations Me2NHSiMe3+ and Me2N(SiMe3)2+.

International audience; The coordination of pyridine-2-amino(methyl)dimethylsilane ligands to ruthenium has afforded access to a family of novel complexes that display multicenter Ru–H–Si interactions according to the number of incorporated ligands. The new complexes Ru[κ-Si,N-(SiMe2)N(Me)(C5H4N)](η4-C8H12)(η3-C8H11) (1), Ru2(μ-H)2(H)2[κ-Si,N-(SiMe2)N(Me)(C5H4N)]4 (2), and Ru(H)[κ-Si,N-(SiMe2)N(Me)(C5H4N)]3 (3) were isolated and fully characterized. The complexes exhibit different degrees of Si–H activation: complete Si–H cleavage, secondary interactions between the atoms (SISHA), and η2-Si–H coordination. Reversible protonation of 3 leading to the cationic complex [RuH{(η2-H-SiMe2)N(Me)κ-N-(C5H4N)}{κ-Si,N-(SiMe2)N(Me)(C5H4N)}2]+[BArF4]− (5) was also demonstrated. The coordination modes in these systems were carefully studied with a combination of X-ray and neutron diffraction analysis, DFT geometry optimization, and multinuclear NMR spectroscopy.

The reactivity of the amino(cyano)borane (i)Pr(2)NBH(CN) (2) towards [RuH(2)(η(2)-H(2))(2)(PCy(3))(2)] (3) was investigated. Our study reveals that the formation of the bis(isocyanoborane) ruthenium complex [RuH(CN)(CN-BHN(i)Pr(2))(2)(PCy(3))(2)] (6) occurs via the intermediacy of the bis(σ-B-H) ruthenium complex [RuH(CN)(H(2)BN(i)Pr(2))(PCy(3))(2)] (5). This transformation involves BCN linkage isomerisation in 2. The diisopropylaminoborane ligand in 5 can be displaced to ultimately produce the bis(σ-borane) complex [RuH(2)(η(2):η(2)-H(2)BN(i)Pr(2))(PCy(3))(2)] (4) as a by-product.

International audience; We evidenced the conversion of an unprecedented intermolecular bridged-proton bimetallic P-metallated phosphoryl complex [{[Ru](Ph2P[double bond, length as m-dash]O)}2H][PF6]3 to its corresponding H-bonded water complex [{[Ru](Ph2P[double bond, length as m-dash]O)}2(H2O)][PF6]2, a rare motif. Their synthesis, NMR data, X-ray crystal structures, electrochemical and photophysical properties are reported.

International audience; A detailed study of the transamination reaction between Ti(NMe2)4 and primary amines RNH2 is reported Alkylamines (1-adamantylamine, t-butylamine) and triphenylsilylamine yield dimers of the type [Ti(μ-NR)(NMe2)2]2 (R = 1-adamantyl (1), tBu (2), SiPh3 (3)). The experimental conditions and the nature of the amine are important issues that determine the scope and yield of the reaction. When reacted under the same conditions, aniline PhNH2 does not yield the expected dimer, but instead the trimer [Ti3(μ2-NPh)3(μ3-NPh)(NMe2)4(NHMe2)] (5) and tetramer [Ti4(μ-NPh)5(NMe2)6] (6) complexes were characterized. The reaction of Ti(NMe2)4 and 2,6-diisopropylaniline (Ar*NH2) is essentially an equilibrium reaction of great complexity in which multiple species can coexist in solution. However, under certain circumstances, we were able to isolate and/or characterize several new complexes such as [Ti(μ-NAr*)(NMe2)2]2 (7), [(Me2N)2Ti(μ-NAr*)2Ti(NMe2)(NHAr*)] (8), [Ti(NMe2)3]2(μ-NAr*) (9), [(Ar*NH)2Ti(μ-NAr*)2Ti(NMe2)2] (10), [(Me2N)(Me2NH)Ti(μ-NAr*)2Ti(NMe2)([double bond, length as m-dash]NAr*)] (11), Ti(NHAr*)4 (12), and [(Ar*NH)2Ti(μ-NAr*)2Ti(NMe2)(NHAr*)] (13). Complexes 8 and 11 are tautomers. Alternatively, complex 7 was prepared by deprotonation of NHMe2 ligands in Ti([double bond, length as m-dash]NAr*)Cl2(NHMe2)2 with KN(SiMe3)2. Addition of pyridine (py) to the reaction of Ti(NMe2)4/Ar*NH2 mixtures or to 7 or 8 allows characterization of transient [Ti(μ-NAr*)(NMe2)2]2·py (14) and trapping of the intermediates [(Me2N)(py)2Ti(μ-NAr*)2Ti(NMe2)([double bond, length as m-dash]NAr*)] (15), Ti([double bond, length as m-dash]NAr*)(NHAr*)(NMe2)(py)2 (16), and Ti([double bond, length as m-dash]NAr*)(NHAr*)2(py)2 (17). The crystal structures of 15 compounds were determined by X-ray diffraction studies.

The complexes F(n)-Tp(4Bo,3Rf)Ag(L) (F(n)-Tp(4Bo,3Rf)=a perfluorinated hydrotris(indazolyl) borate ligand; L=acetone or tetrahydrofuran) efficiently catalyze the functionalization of non-activated alkanes such as hexane, 2,3-dimethylbutane, or 2-methylpentane by insertion of CHCO(2)Et units (from N(2)CHCO(2)Et, ethyl diazoacetate, EDA) into their C-H bonds. The reactions are quantitative (EDA-based), with no byproducts derived from diazo coupling being formed. In the case of hexane, the functionalization of the methyl C-H bonds has been achieved with the highest regioselectivity known to date with this diazo compound. This catalytic system also operates under biphasic conditions by using fluorous solvents such as Fomblin or perfluorophenanthrene. Several cycles of catalyst recovery and reuse have been performed, with identical chemo- and regioselectivities.

A new process for the preparation of antimony and bismuth(III) triflates has been found. This process is based on the reaction of triflic acid on metal oxide using chlorobenzene as a solvent. Due to its simplicity, this process can be useful for the laboratory scale as well as the industrial preparation of these metal triflates.

International audience; The synthesis and characterization of three monohydroxido‐bridged dinuclear CuII complexes, [{Cu2(L1)2(μ‐OH)}(ClO4){Cu2(L1)2(μ‐OH)}](ClO4)· 5.5H2O (1 ), Cu2(L2)2(OH)(ClO4)(H2O)2 (2 ), [{Cu2(L3)2(μ‐OH)(ClO4)}2]· 5H2O (3 ) and three monohydroxido‐bridged trinuclear CuII complexes, [Cu3(L4)3(μ3‐OMe)(ClO4)2] (4 ), [Cu3(L5)3(μ3‐OH) (ClO4)2]· 0.5{(CH3)2CO}· 0.5(H2O) (5 ), [Cu3(L6)3(μ3‐OH)(ClO4)2] (6 ), is reported (HL1–HL6 = tridentate N2O ligands resulting from the Schiff base condensation of salicylaldehyde or 3‐methoxysalicylaldehyde with ethylenediamine, 1,2‐diaminopropane, 2‐methylpropane‐1,2‐diamine or 1,2‐diaminocyclohexane). The six new complexes are obtained through aggregation of the corresponding mononuclear precursor Cu(Li )(py)(ClO4) in the presence of HO– (MeO–) anions in methanol. The nuclearity of the resulting complex depends on the steric requirement of Li : in the presence of an OMe substituent α to the Ophenoxido atom (L1–L3), μ‐HO– single‐bridged dinuclear compounds are obtained (1 –3 ); in the absence of an α‐substituent (L4–L6), the aggregation proceeds to the μ3‐OH– (μ3‐OMe–) bridged trinuclear compounds 4 –6 . The molecular structures of 1 , 3 and 4 –6 have been established through single‐crystal X‐ray studies. Antiferromagnetic interactions operate in 1 (J = –57 cm–1, –2JS 1S 2 formalism), 2 is paramagnetic, and 3 is the first example of a ferromagnetic monohydroxido‐bridged dinuclear CuII complex (J = 16 cm–1). The structural and magnetic parameters for the 22 μ‐HO– single‐bridged dinuclear CuII compounds reported to date are compared. Antiferromagnetic interactions operate in all three monohydroxido‐bridged trinuclear CuII complexes 4 , 5 , and 6 (J = –16.9, –6.3, and –6.7 cm–1, respectively). The structural and magnetic parameters for the seven μ3‐hydroxido (methoxido) bridged trinuclear CuII compounds presently known in the series based on tridentate Schiff bases that result from condensation of diamines with salicylaldehydes are compared.

Key feature of the presented synthesis is the nitration of terpyridine N,N′′-dioxide (II) in fuming nitric acid and fuming sulfuric acid with concomitant reduction of the N-oxides [cf.

The control of nanocrystal structures at will is still a challenge, despite the recent progress of colloidal synthetic procedures. It is common knowledge that even small modifications of the reaction parameters during synthesis can alter the characteristics of the resulting nano-objects. In this work we report an unexpected factor which determines the structure of cobalt nanoparticles. Nanocrystals of distinctly different sizes and shapes have resulted from stock solutions containing exactly the same concentrations of [Co{N(SiMe(3))(2)}(2)(thf)], hexadecylamine, and lauric acid. The reduction reaction itself has been performed under identical conditions. In an effort to explain these differences and to analyze the reaction components and any molecular intermediates, we have discovered that the rate at which the cobalt precursor is added to the ligand solution during the stock solution preparation at room temperature becomes determinant by triggering off a nonanticipated side reaction which consumes part of the lauric acid, the main stabilizing ligand, transforming it to a silyl ester. Thus, an innocent mixing, apparently not related to the main reaction which produces the nanoparticles, becomes the parameter which in fine defines nanocrystal characteristics. This side reaction affects in a similar way the morphology of iron nanoparticles prepared from an analogous iron precursor and the same long chain stabilizing ligands. Side reactions are potentially operational in a great number of systems yielding nanocrystals, despite the fact that they are very rarely mentioned in the literature.

International audience; The serendipity synthesis of the 2-hydroxy-3-methoxy-benzaldehyde or o -vanillin nickel(II) cubane complex, obtained by ourselves and other workers, can be rationalized to give the cubane in a high yield by direct use of 2-hydroxy-3-methoxy-benzaldehyde (H-ovan). The structural determinations of crystals obtained according to the two experimental processes show that the complex formulated [(MeOH)Ni(μ3 -OMe)(ovan)]4 (ovan=deprotonated form of o -vanillin) is characterized in the two cases. Ni-Ni ferromagnetic interactions (J NiNi =5.8cm−1) giving an S =4 ground state are active in the Ni4 cubane. Replacement of methanol molecules coordinated to the Ni ions by a diol, an amino-alcohol or an amino-ether allows self-association of these Ni4 units according to two different ways: by direct coordination bonds through the diol ligand or by hydrogen bonds involving the OMe groups of o -vanillin located at the periphery of the cubane and the hydrogen atoms of the primary amine functions. This association is suggested in the two cases by the presence of out-of-phase signals (χ ”) when ac susceptibility measurements are performed at different frequencies. These molecules do not behave as SMM for these χ ” signals, that are not frequency-dependent, correspond to the establishment of a three-dimensional ordering.; Un complexe tétranucléaire du nickel, obtenu par hasard dans un premier temps, a été ensuite préparé en grande quantité grâce à un procédé décrit dans cet article. Les déterminations structurales des cristaux obtenus selon les deux processus expérimentaux montrent que l’on isole un même complexe de formule [(MeOH)Ni(μ3 -OMe)(ovan)]4 . Ce cubane Ni4 est le siège d’interactions Ni-Ni ferromagnétiques (J NiNi =5,8cm−1) conduisant à un état fondamental S =4 mais il ne se comporte pas comme une molécule-aimant. Le remplacement des molécules de méthanol coordinées au nickel par un diol, le 1,3-propanediol, permet d’associer ces cubanes. Une autre façon d’assembler ces entités tétranucléaires consiste à remplacer les molécules de méthanol par autant de molécules amino-alcool ou amino-éther. Ces dernières se complexent au nickel par leurs fonctions oxygénées tandis que leurs fonctions amine primaire établissent un réseau de liaisons hydrogène avec les groupements OMe portés par l’o -vanilline et situés à la périphérie du cubane. Cette auto-association est confirmée par l’apparition d’un signal de susceptibilité magnétique imaginaire (χ ”) obtenu lors de mesures de susceptibilité en mode alternatif à différentes fréquences. La non-dépendance en fréquence de ces signaux ne correspond pas à un comportement de molécule-aimant mais est reliée à l’établissement d’un ordre magnétique tridimensionnel.

International audience; Tetranuclear [Co–Gd]2 complexes were prepared by using trianionic ligands possessing amide, imine, and phenol functions. The structural determinations show that the starting cobalt complexes present square planar or square pyramid environments that are preserved in the final tetranuclear [Co–Gd]2 complexes. These geometrical modifications of the cobalt coordination spheres induce changes in the cobalt spin ground states, going from S = 1/2 in the square planar to S = 3/2 for the square pyramid environments. Depending on the ligand, the complexes display antiferromagnetic or ferromagnetic CoII–GdIII interactions. The temperature dependence of the magnetic susceptibility-temperature products indicate that the Co–Gd interaction is ferromagnetic when high spin Co ions are concerned and antiferromagnetic in the case of low spin Co ions. This different magnetic behavior can be explained if we observe that the singly occupied σ dx2–y2 orbital is populated (S = 3/2 Co ions) or unoccupied (S = 1/2 Co ions). Such an observation furnishes invaluable information for the understanding of the more general 3d-4f magnetic interactions.

The synthesis and characterization (mainly by (19)F NMR and X-ray diffraction) of highly fluorinated aryl-4,5,6,7-tetrafluoroindazoles and their corresponding thallium hydrotris(indazolyl)borate complexes are reported [aryl = phenyl, pentafluorophenyl, 3,5-dimethylphenyl, 3,5-bis(trifluoromethyl)phenyl]. Thanks to N-H···N hydrogen bonds, the indazoles crystallize as dimers that pack differently depending on the nature of the aryl group. The thallium hydrotris(indazolyl)borate complexes Tl[Fn-Tp(4Bo,3aryl)] resulting from the reaction of aryl-4,5,6,7-tetrafluoroindazoles [aryl = phenyl, 3,5-dimethylphenyl, 3,5-bis(trifluoromethyl)phenyl] with thallium borohydride adopt overall C(3v) symmetry with the indazolyl groups bound to boron via their N-1 nitrogen in a conventional manner. When the perfluorinated pentaphenyl-4,5,6,7-tetrafluoroindazole is reacted with thallium borohydride, a single regioisomer of C(s) symmetry having one indazolyl ring bound to boron via its N-2 nitrogen, TlHB(3-pentafluorophenyl-4,5,6,7-tetrafluoroindazol-1-yl)(2)(3-pentafluorophenyl-4,5,6,7-tetrafluoroindazol-2-yl) Tl[F27-Tp((4Bo,3C6F5)*)], is obtained for the first time. Surprisingly, the perfluorinated dihydrobis(indazolyl)borate complex Tl[F(18)-Bp(3Bo,3C6F5)], an intermediate on the way to the hydrotris(indazolyl)borate complex, has C(s) symmetry with two indazolyl rings bound to boron via N-2. The distortion of the coordination sphere around Tl and the arrangement of the complexes in the crystal are discussed.

International audience; Thirty new cycloartane derivatives (1–3, 5–12, 14–32) have been isolated from the leaves of Neoboutonia melleri. Their novelty stems from the loss of one of the C-4 methyl groups (1–3, 5–12, 14–25, and 32) and from the presence of an “extra” carbon atom in the side chain (1–3, 5–12, 14–20, 26–29, and 30–32). Furthermore, compound 32 possesses a rare triterpene skeleton with the cyclopropane ring fused onto C-1 and C-10, instead of C-9 and C-10. The structures were determined by spectrometric means, chemical correlations, and X-ray crystallography of derivative 1c. The substitution pattern in ring A, with a cyclopropyl ring conjugated with an α,β-unsaturated carbonyl moiety, confers to the molecule a particular reactivity, giving rise to a formal inversion of the stereochemistry of the cyclopropane ring under UV irradiation. These compounds showed an interesting level of activity on the proteasome pathway, thus motivating their evaluation as possible anticancer agents. The large number of isolated compounds permitted a structure–activity relationship analysis, which showed that the presence of the two enone functions was a requirement for the activity.

International audience; The effect of pressure on the dinuclear spin crossover material [{Fe(bpp)(NCS)(2)}(2)(4,4'-bipy)]*2MeOH (where bpp = 2,6-bis(pyrazol-3-yl)pyridine and 4,4'-bipy = 4,4'-bipyridine, 1) has been investigated with single crystal X-ray diffraction and Raman spectroscopy using diamond anvil cell techniques. The very gradual pressure-induced spin crossover occurs between 7 and 25 kbar, and shows no evidence of crystallographic phase transitions. The pressure-induced spin transition leads to a complete LS state which is not thermally accessible. This structural evolution under pressure is in stark contrast to the previously reported thermal spin crossover behaviour, in which a symmetry-breaking, purely structural phase transition results in only partial conversion to the low spin state. This observation is attributed to the symmetry-breaking phase transition becoming unfavourable under pressure.

A single crystal of KVTeO(5), potassium vanadium tellurite, has been grown. The present structure determination has been conducted together with the refinement of the NaVTeO(5) homologue, sodium vanadium tellurite, for the sake of precise comparison. The network consists of [VTeO(5)](n) ribbons built up by VO(4) tetrahedra linking centrosymmetric Te(2)O(6) groups and stacked along the [010] direction; the alkali cations are intercalated in between. The Te(IV) atom exhibits a typical one-sided coordination number (CN) of 4, completed by a lone pair, which forms a distorted triangular bipyramid with the four O atoms.

A method for large scale preparation of Bi(OTf)3 from Bi2O3 in a weakly hydrated form after freeze-drying.

International audience; Unexpected room temperature luminescence is observed and rationalized by highly challenging excited state calculations for a functionalized phosphine ligand coordinated on the [Ru(bpy)(tpy)](2+) core.

International audience; One and two : The C2 compound pinBOCH2OCHO (see scheme; HBpin=pinacolborane) and several C1 compounds have been obtained from the borane‐mediated reduction of CO2 under mild conditions with the catalyst precursor [RuH2(H2)2(PCy3)2]. Mechanistic investigation highlights the role of a series of new carbonyl ruthenium complexes that were characterized by multinuclear NMR spectroscopy, IR spectroscopy, and X‐ray diffraction studies.