Electroactive 1,5-benzodiazepines bearing either a tetrathiafulvalene or a ferrocene moiety

International audienceThe synthesis of a series of electroactive 1,5-benzodiazepines bearing either a ferrocene or tetrathiafulvalene core, acting as the electroactive moiety, is reported. The electron donating ability of these redox active 1,5-benzodiazepines is described together with their molecular structures, investigated by X-ray diffraction studies

Chiral electron-rich bis(cyclopentadienyl) dithiolene molybdenum complexes

International audienceEnantiomerically pure electron rich Cp2Mo(dithiolene) complexes have been synthesized from the enantiopure dithiolene ligands, namely the (R)- and the (S)-3(1-phenylethyl)-1,3-thiazoline-2-thione-4,5-dithiolate ligands. These heteroleptic molybdenum complexes act as very good electron donors, as demonstrated through electrochemical investigations. Both isomers form charge transfer salts with TCNQ with a 1:1 stoechiometry which have been characterized by single crystal X-ray diffraction, EPR and UV–vis spectroscopic investigations. Circular dichroism (CD) experiments were also carried out on the neutral (R) and (S) enantiomers as well as on the mono oxidized species of these Cp2Mo dithiolene complexes

A new approach towards ferromagnetic conducting materials based on TTF-containing polynuclear complexes

International audienceFive complexes containing binuclear cation [Cu2(LH)2]2+ (LH2 = 1 : 2 Schiff base of 1,3-diaminobenzene and butanedione monoxime) were prepared and characterized. Metathesis of one perchlorate anion in [Cu2(LH)2(H2O)2](ClO4)2 (1) by anionic TTF-carboxylate (TTF-CO2−) leads to the complex [Cu2(LH)2(CH3OH)2](TTF-CO2)(ClO4)*H2O (2). Reactions of 1 with substituted pyridines bipy, dpe and TTF-CH = CH-py result in formation of the complexes {[Cu2(LH)2(bipy)](ClO4)2}n*2nH2O (3), [Cu2(LH)2(dpe)2](ClO4)2*2CH3OH (4) and [Cu2(LH)2(TTF-CH = CH-py)(H2O)](ClO4)2*1.5H2O (5), where bipy = 4,4′-bipyridine, dpe = trans-(4-pyridyl)-1,2-ethylene and TTF-CH = CH-py = 1-(2-tetrathiafulvalenyl)-2-(4-pyridyl)ethylene. Whereas complex 2 is built from discrete ionic particles (with rather long Cu-S contacts), compounds 1 and 3 contain 1D polymeric chains, in which structural units are bonded through Cu-O bonds or through bridging bipy molecule, respectively. Dinuclear complexes 4 and 5 are linked though π-stacking of dpe or TTF-CH = CH-py, respectively. All complexes are characterized by dominating ferromagnetic behavior with J values in the range from +9.92(8) cm−1 to +13.4(2) cm−1 for Hamiltonian H = -JS1S2. Magnetic properties of the compounds, containing stacks of aromatic molecules in crystal structures (4 and 5), correspond to ferromagnetic intradimer and antiferromagnetic intermolecular interactions (zJ′ = −0.158(3) and −0.290(2) cm−1, respectively). It was found that TTF-CH = CH-py ligand in [Cu2(LH)2(TTF-CH = CH-py)(H2O)]2+ could be electrochemically oxidized to cation-radical form in the solution

Mixed-valence gold bis (diselenolene) complex turning metallic under pressure.

While oxidation of d8 anionic gold bis(dithiolene) complexes most often affords the corresponding neutral radical single-component conductor, an original gold bis(diselenolene) complex isolated as a Ph4P+ salt affords upon electrocrystallization a mixed-valence 1 : 2 salt, [Ph4P][Au(Me-thiazds)2]2 (Me-thiazds: 2-methyl-1,3-thiazoline-2-thione-4,5-diselenolate). This salt exhibits a rare charge alternation associated with the simultaneous presence of both cis and trans isomers of the gold complex in the conducting layers. The salt is semiconducting (σRT = 3 × 10−2 S cm−1, Eact = 0.137 eV) but, in contrast with other 1 : 2 gold bis(dithiolene) salts, turns metallic under pressure (>10 GPa). [Ph4P][Au(Me-thiazds)2]2 is thus the first metallic, fully characterized, 1 : 2 mixed-valence gold complex, opening the door for the preparation of highly conducting solids of this type

Molecules with ALMA at Planet-forming Scales (MAPS). XVIII. Kinematic substructures in the disks of HD 163296 and MWC 480

Funding: K.Z., K.R.S., J.H., J.B., J.B.B., and I.C. acknowledge the support of NASA through Hubble Fellowship grants HST-HF2-51401.001, HST-HF2-51419.001, HST-HF2-51460.001-A, HSTHF2-51427.001-A, HST-HF2-51429.001-A, and HST-HF2-51405.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. A.S.B. acknowledges the studentship funded by the Science and Technology Facilities Council of the United Kingdom (STFC). C.W. acknowledges financial support from the University of Leeds, STFC, and UKRI (grant Nos. ST/R000549/1, ST/T000287/1, MR/T040726/1).We explore the dynamical structure of the protoplanetary disks surrounding HD 163296 and MWC 480 as part of the Molecules with ALMA at Planet-forming Scales (MAPS) large program. Using the J = 2-1 transitions of 12CO, 13CO, and C18O imaged at spatial resolutions of ~0"15 and with a channel spacing of 200 m s-1, we find perturbations from Keplerian rotation in the projected velocity fields of both disks (≲5% of the local Keplerian velocity), suggestive of large-scale (tens of astronomical units in size), coherent flows. By accounting for the azimuthal dependence on the projection of the velocity field, the velocity fields were decomposed into azimuthally averaged orthogonal components, vφ, vr, and vz. Using the optically thick 12CO emission as a probe of the gas temperature, local variations of ≍3 K (≍5% relative changes) were observed and found to be associated with the kinematic substructures. The MWC 480 disk hosts a suite of tightly wound spiral arms. The spirals arms, in conjunction with the highly localized perturbations in the gas velocity structure (kinematic planetary signatures), indicate a giant planet, ~1 MJup, at a radius of ≍245 au. In the disk of HD 163296, the kinematic substructures were consistent with previous studies of Pinte et al. and Teague et al. advocating for multiple ~1 MJup planets embedded in the disk. These results demonstrate that molecular line observations that characterize the dynamical structure of disks can be used to search for the signatures of embedded planets. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.Publisher PDFPeer reviewe

Molecules with ALMA at Planet-forming Scales (MAPS). I. Program overview and highlights

Funding: I.C. was supported by NASA through the NASA Hubble Fellowship grant HST-HF2-51405.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. C.W. acknowledges financial support from the University of Leeds, Science and Technology Facilities Council of the United Kingdom (STFC), and UKRI (grant Nos. ST/R000549/1, ST/T000287/1, MR/T040726/1).Planets form and obtain their compositions in dust- and gas-rich disks around young stars, and the outcome of this process is intimately linked to the disk chemical properties. The distributions of molecules across disks regulate the elemental compositions of planets, including C/N/O/S ratios and metallicity (O/H and C/H), as well as access to water and prebiotically relevant organics. Emission from molecules also encodes information on disk ionization levels, temperature structures, kinematics, and gas surface densities, which are all key ingredients of disk evolution and planet formation models. The Molecules with ALMA at Planet-forming Scales (MAPS) ALMA Large Program was designed to expand our understanding of the chemistry of planet formation by exploring disk chemical structures down to 10 au scales. The MAPS program focuses on five disks-around IM Lup, GM Aur, AS 209, HD 163296, and MWC 480-in which dust substructures are detected and planet formation appears to be ongoing. We observed these disks in four spectral setups, which together cover ~50 lines from over 20 different species. This paper introduces the Astrophysical Journal Supplement's MAPS Special Issue by presenting an overview of the program motivation, disk sample, observational details, and calibration strategy. We also highlight key results, including discoveries of links between dust, gas, and chemical substructures, large reservoirs of nitriles and other organics in the inner disk regions, and elevated C/O ratios across most disks. We discuss how this collection of results is reshaping our view of the chemistry of planet formation.Publisher PDFPeer reviewe

Model-Based Design of Flexible and Efficient LDPC Decoders on FPGA Devices

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Effect of ZrO2, TiO2, and Al2O3 Additions on Process and Kinetics of Bonelike Apatite Formation on Sintered Natural Hydroxyapatite SurfaceS

International audienceIn this study, the ability to form bone-like apatite on surface of both pure natural hydroxapatite (N-HA) and natural hydroxyapatite containing 5 wt% of ZrO2 or TiO2 or Al2O3, sintered at 1300°C for 2 h and soaked in the simulated body fluid for different times, was studied. It has been found that the presence of β-tricalcium phosphate in N-HA + 5 wt% ZrO2 or TiO2 has promoted the precipitation of bone-like apatite in the Zr or Ti poorest regions. By contrast, the presence of 5 wt% of Al2O3 did not induce any apatite precipitation on N-HA sample surfaces

La vocation du Prince

Qu’est-ce que la vocation à l’aube de l’époque moderne ? Issu du verbe vocare, le substantif latin vocatio signifie « appel ». Aussi la vocation a-t-elle pour sens premier l’appel à accomplir la volonté divine. Mais loin de s’intéresser à l’appel aux ordres ou à la vie religieuse, ce volume entend considérer plus généralement la vocation comme la destination d’une personne, ici le prince, ou encore l’inclination pour un état ou une profession, ce que Max Weber assimilait à un « dévouement » dans le domaine politique. Le prince, par son caractère d’élu, est animé par une vocation dont la finalité n’est ainsi pas exclusivement celle d’accomplir une mission divine. Se mêlent la part de l’être déterminé par son devenir – et préparé à cela – et celle de la volonté propre qui donne sa marque à cette vocation à laquelle il ne doit pas être possible d’échapper