Papers by Sébastien Bontemps
Dalton Transactions
The synthesis of quasilinear metal(i) silylamides [KM(N(Dipp)SiR3)2] of chromium to cobalt, their... more The synthesis of quasilinear metal(i) silylamides [KM(N(Dipp)SiR3)2] of chromium to cobalt, their diverse speciation in solid state and solution as well as their reactivity towards alkynes are reported.
Dalton Transactions
Two known and two new ortho-phenyl phosphonium–sulfonate compounds have been synthesized and anal... more Two known and two new ortho-phenyl phosphonium–sulfonate compounds have been synthesized and analyzed in solution and in the solid state.
Dalton Transactions
Iron(I) species are debated as key intermediates during the C-halide activation step in Kumuda ty... more Iron(I) species are debated as key intermediates during the C-halide activation step in Kumuda type C–C cross-coupling catalysis. However, there is only limited and contradictive evidence on the reactivity of...
Chemistry - A European Journal, 2015
Anionic two-coordinate complexes of first-row transition-metal(I) centres are rare molecules that... more Anionic two-coordinate complexes of first-row transition-metal(I) centres are rare molecules that are expected to reveal new magnetic properties and reactivity. Recently, we demonstrated that a N(SiMe3 )2 (-) ligand set, which is unable to prevent dimerisation or extraneous ligand coordination at the +2 oxidation state of iron, was nonetheless able to stabilise anionic two-coordinate Fe(I) complexes even in the presence of a Lewis base. We now report analogous Cr(I) and Co(I) complexes with exclusively this amido ligand and the isolation of a [Mn(I) {N(SiMe3 )2 }2 ]2 (2-) dimer that features a Mn-Mn bond. Additionally, by increasing the steric hindrance of the ligand set, the two-coordinate complex [Mn(I) {N(Dipp)(SiMe3 )}2 ](-) was isolated (Dipp=2,6-iPr2 -C6 H3 ). Characterisation of these compounds by using X-ray crystallography, NMR spectroscopy, and magnetic susceptibility measurements is provided along with ligand-field analysis based on CASSCF/NEVPT2 ab initio calculations.
Journal of the American Chemical Society, Jan 5, 2015
We report herein the use of the (dihydrido)iron catalyst, Fe(H)2(dmpe)2, for the selective reduct... more We report herein the use of the (dihydrido)iron catalyst, Fe(H)2(dmpe)2, for the selective reduction of CO2 into either bis(boryl)acetal or methoxyborane depending on the hydroborane used as a reductant. In a one-pot two-step procedure, the in situ generated bis(boryl)acetal was shown to be a reactive and versatile source of methylene to create new C-N but also C-O and C-C bonds.
Coordination Chemistry Reviews, 2015
ABSTRACT
Journal of the American Chemical Society, 2015
Well-defined iron bis(diphosphine) complexes are active catalysts for the dehydrogenative C-H bor... more Well-defined iron bis(diphosphine) complexes are active catalysts for the dehydrogenative C-H borylation of aromatic and heteroaromatic derivatives with pinacolborane. The corresponding borylated compounds were isolated in moderate to good yields (25-73%) with a 5 mol% catalyst loading under UV irradiation (350 nm) at room temperature. Stoichiometric reactivity studies and isolation of an original trans-hydrido(boryl)iron complex, Fe(H)(Bpin)(dmpe)2, allowed us to propose a mechanism showing the role of some key catalytic species.
Angewandte Chemie (International ed. in English), Jan 2, 2015
First-row two-coordinate complexes are attracting much interest. Herein, we report the high-yield... more First-row two-coordinate complexes are attracting much interest. Herein, we report the high-yield isolation of the linear two-coordinate iron(I) complex salt [K(L)][Fe{N(SiMe3 )2 }2 ] (L=18-crown-6 or crypt-222) through the reduction of either [Fe{N(SiMe3 )2 }2 ] or its three-coordinate phosphine adduct [Fe{N(SiMe3 )2 }2 (PCy3 )]. Detailed characterization is gained through X-ray diffraction, variable-temperature NMR spectroscopy, and magnetic susceptibility studies. One- and two-electron oxidation through reaction with I2 is further found to afford the corresponding iodo iron(II) and diiodo iron(III) complexes.
Organometallics, 2013
Crystallographic Experimental Section Data Collection An irregular broken fragment (0.24 x 0.20 x... more Crystallographic Experimental Section Data Collection An irregular broken fragment (0.24 x 0.20 x 0.16 mm) was selected under a stereo-microscope while immersed in Fluorolube oil to avoid possible reaction with air. The crystal was removed from the oil using a tapered glass fiber that also served to hold the crystal for data collection. The crystal was mounted and centered on a Bruker SMART APEX system at 100 K. Rotation and still images showed the diffractions to be sharp. Frames separated in reciprocal space were obtained and provided an orientation matrix and initial cell parameters. Final cell parameters were obtained from the full data set. A "full sphere" data set was obtained which samples approximately all of reciprocal space to a resolution of 0.75 Å using 0.3 o steps in using 10 second integration times for each frame. Data collection was made at 100 K. Integration of intensities and refinement of cell parameters were done using SAINT [1]. Absorption corrections were applied using SADABS [1] based on redundant diffractions. Structure solution and refinement The space group was determined as C2/c based on systematic absences and intensity statistics. Direct methods were used to locate the Pdl atom and many C atoms from the E-map. Repeated difference Fourier maps allowed recognition of all expected Pd, P, S, N, O and C atoms. Following anisotropic refinement of all non-H atoms, ideal H-atom positions were calculated. Final refinement was anisotropic for all non-H atoms, and isotropic-riding for H atoms. No anomalous bond lengths or thermal parameters were noted. All ORTEP diagrams have been drawn with 50% probability ellipsoids.
Journal of the American Chemical Society, 2006
Journal of the American Chemical Society, 2014
Functionalization of CO2 is a challenging goal and precedents exist for the generation of HCOOH, ... more 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.
Inorganic Chemistry, 2013
Three naphthyl-bridged phosphine-borane derivatives 2-BCy2, 2-BMes2, and 2-BFlu, differing in the... more Three naphthyl-bridged phosphine-borane derivatives 2-BCy2, 2-BMes2, and 2-BFlu, differing in the steric and electronic properties of the boryl moiety, have been prepared and characterized by spectroscopic and crystallographic means. The presence and magnitude of the P → B interactions have been assessed experimentally and theoretically. The naphthyl linker was found to enforce the P → B interaction despite steric shielding, while retaining enough flexibility to respond to the Lewis acidity of boron.
Inorganic Chemistry, 2007
Spectroscopic, structural, and theoretical evidence is provided for both open (no intramolecular ... more Spectroscopic, structural, and theoretical evidence is provided for both open (no intramolecular P --> B interaction) and closed (with intramolecular P --> B interaction) forms of the di- and tri-phosphine boranes [o-(iPr(2)P)C(6)H(4)](2)BPh (2) and [o-(iPr(2)P)C(6)H(4)](3)B (3).
Chemistry - A European Journal, 2008
Coordination of an ambiphilic diphosphine-borane (DPB) ligand to the RhCl(CO) fragment affords tw... more Coordination of an ambiphilic diphosphine-borane (DPB) ligand to the RhCl(CO) fragment affords two isomeric complexes. According to X-ray diffraction analysis, each complex adopts a square-pyramidal geometry with trans coordination of the two phosphine buttresses and axial RhB contacts, but the two differ in the relative orientations around the rhodium and boron centres. DFT calculations on the actual complexes provide insight into the influence of the pi-accepting CO co-ligand, compared with previously reported complexes [Rh(mu-Cl)(dpb)]2 and [RhCl(dmap)(dpb)]. In addition, comparison of the nu(CO) frequency of [RhCl(CO)(dpb)] with that of the related borane-free complex [RhCl(CO)(iPr2PPh)2] substantiates the significant electron-withdrawing effect that the sigma-accepting borane moiety exerts on the metal. Valence isoelectronic [PtCl2(dpb)] and [PdCl2(dpb)] complexes have also been prepared and characterized spectroscopically and structurally. The pronounced influence of the transition metal on the magnitude of the M-->B interaction is highlighted by geometric considerations and NBO analyses.
Angewandte Chemie International Edition, 2007
Scheme 1. Structurally characterized complexes featuring M!BR 3 interactions. Scheme 2. The two l... more Scheme 1. Structurally characterized complexes featuring M!BR 3 interactions. Scheme 2. The two limiting bonding situations for dative M!BR 3 interactions proposed by Hill [20a] and Parkin, [20b] respectively.
Uploads
Papers by Sébastien Bontemps