Search results for "Cristallography"
showing 10 items of 65 documents
Synthesis of FeAl Hetero-Nanostructured Bulk Parts via Spark Plasma Sintering of Milled Powder
2006
AbstractSpark plasma sintering (SPS) has been used in order to introduce nanocrystalline grains within fully dense FeAl consolidated parts. Hetero-nanostructured parts, consisting of nano, ultrafine and micrometric grains, have been successfully processed when milled - Y2O3 reinforced - FeAl powder was used. The large temperature differences that are spontaneously generated during the SPS process as well as the use of milled powder account for the formation of such interesting structures. The grain size distribution - that is suggested to be very potent to improve both strength and ductility - could be significantly modified by a proper selection of sintering temperature and holding time.
Spin crossover (SCO) iron(II) coordination polymer chain: Synthesis, structural and magnetic characterizations of [Fe(abpt)2(μ-M(CN)4)] (M=PtII and N…
2013
Abstract New iron(II) coordination polymeric neutral chain of formula [Fe(abpt) 2 (μ-M(CN) 4 )], with M = Pt II ( 1 ), Ni II ( 2 ) and abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole, have been synthesized and characterized by infrared spectroscopy, X-ray diffraction and magnetic measurements. The two compounds are isostructural as deduced from a Rietveld analysis of X-ray powder diffraction data of 2 simulated from the single crystal structure of 1 . The crystal packing of 1 is formed by regular chains running along the crystallographic [−1 0 1] direction where the planar [Pt(CN) 4 ] 2− anion acts as a μ 2 -bridging ligand via two nitrogen atoms of two different trans cyano groups, whi…
A polar/π model of interactions explains face-to-face stacked quinoid rings: a case study of the crystal of potassium hydrogen chloranilate dihydrate
2015
International audience; The nature of interactions between face-to-face staggered stacked quinoid rings with pi-systems, observed with a short inter-ring centroid. centroid distance, is analyzed by experimental and theoretical methods. Charge density studies based on X-ray diffraction and DFT calculations, complemented by impedance spectroscopy, were employed to define the electronic and structural characteristics of the quinoid rings responsible for their interactions within the crystal packing. The crystal packing is mainly stabilized by strong electrostatic interactions between the K+ cation and the hydrogen chloranilate anion. The proximity and orientation of the stacked quinoid rings i…
Fishing anti-inflammatories from known drugs: In silico repurposing, design, synthesis and biological evaluation of bisacodyl analogues
2017
Herein is described in silico repositioning, design, synthesis, biological evaluation and structure-activity relationship (SAR) of an original class of anti-inflammatory agents based on a polyaromatic pharmacophore structurally related to bisacodyl (BSL) drug used in therapeutic as laxative. We describe the potential of TOMOCOMD-CARDD methods to find out new anti-inflammatory drug-like agents from a diverse series of compounds using the total and local atom based bilinear indices as molecular descriptors. The models obtained were validated by biological studies, identifying BSL as the first anti-inflammatory lead-like using in silico repurposing from commercially available drugs. Several bi…
Conception et synthèse de nouvelles sondes fluorogéniques à coeur Bodipy pour la détection
2020
Therefore this project is aimed at the development of novel improved multi-analyte fluorogenic probes for heavy metals ions and bioanalytes within the framework “AND” fluorescent molecular logic gates concept. The biothiols and cations of Cd(II), Pb(II), Cr(III) and Cu(II) heavy metals will be selected as the targeted analytes. To the best of our knowledge, no “AND” molecular logic gates using metal ions besides Zn(II), Hg(II), Ca(II) inputs, likewise no multi-analyte probes for biothiols along with heavy metal cations, has been described in the literature. While the development of a highly sensitive and selective recognition of thiols and metal cations has emerged as a significant interest…
Spin Crossover Iron(II) Coordination Polymer Chains: Syntheses, Structures, and Magnetic Characterizations of [Fe(aqin) 2 (μ 2 -M(CN) 4 )] (M = Ni(II…
2014
International audience; New Fe(II) coordination polymeric neutral chains of formula [Fe(aqin)2(μ2-M(CN)4)] (M = NiII (1) and PtII (2)) (aqin = Quinolin-8-amine) have been synthesized and characterized by infrared spectroscopy, X-ray diffraction, and magnetic measurements. The crystal structure determinations of 1–2 reveal in both cases a one-dimensional structure in which the planar [M(CN)4]2– (M = NiII (1) and PtII (2)) anion acts as a μ2-bridging ligand, and the two aqin molecules as chelating coligands. Examination of the intermolecular contacts in the two compounds reveals that the main contacts are ascribed to hydrogen bonding interactions involving the amine groups of the aqin chelati…
New insights on the electronic, magnetic, electric and molecular structure of a bis-(4-cyanopyridine) iron(III) complex with the meso-tetrakis(4-meth…
2019
International audience; We have successfully synthesized and characterized a new low-spin iron(III) bis(4-cyanopyridine) complex with a meso-porphyrin substituted in the para positions of the phenyls by the methoxy group, namely the bis(4-cyanopyridine)[(meso-tetrakis(4-metoxyphenylporphyrinato)]iron(III) trifluoromethanesulfonate chlorobenzene monosolvate complex with the formula [FeIII(TMPP)(4-CNpy)2]SO3CF3.C6H5Cl (I). This species was characterized through ultraviolet–visible, Fourier-transform infrared and Mössbauer spectroscopy as well as by SQUID magnetometry, cyclic voltammetry, and X-ray crystallography. These characterizations indicated that our synthetic heme model is a low-spin (…
Effects of preorganization in the chelation of UO22+ by hydroxamate ligands: cyclic PIPO– vs linear NMA–
2018
International audience; Many siderophores incorporate as bidentate chelating subunits linear and more seldomly cyclic hydroxamate groups. In this work, a comparative study of the uranyl binding properties in aqueous solution of two monohydroxamic acids, the prototypical linear N-methylacetohydroxamic acid (NMAH) and the cyclic analog 1-hydroxypiperidine-2-one (PIPOH), has been carried out. The complex [UO2(PIPO)(2)(H2O)] crystallized from slightly acidic water solutions (pH < 5), and its molecular structure was determined by X-ray diffraction. The uranyl speciation in the presence of both ligands has been thoroughly investigated in a 0.1 M KNO3 medium at 298.2 K by the combined use of four …
Designing dicyanamide bridged 1D molecular architecture from a mononuclear copper(II) Schiff base precursor: Syntheses, structural variations and mag…
2009
International audience; A new tridentate N2O donor Schiff base ligand [(C6H5C(OH)CHC(CH3)NCH2C5H4N)LH] was obtained by 1:1 condensation of benzoylacetone with 2-picolylamine and has been used to synthesise a mononuclear [CuLCl] (1) and an end-to-end dicyanamide bridged polynuclear {[Cu2(μ-L)2(μ2-1,5-(CN)2N)]ClO4}n (2) copper(II) complexes. The ligand, 1 and 2 were clearly characterised by elemental analysis, FT-IR, 1H NMR, UV–Vis spectral studies, electrochemical studies and in addition single crystal X-ray diffraction studies were performed for 1 and 2. The Schiff base ligand [LH] shows a significant variation in its coordination behaviour with copper(II) ion in absence and in presence of …
Dialkyl(butadiene)cyclopentadienylmolybdenum(III) Complexes. Synthesis, Characterization, and Reactivity
2000
International audience; Treatment of CpMo(η4-diene)Cl2 (diene = 1,3-butadiene, C4H6, 1‘; isoprene, C5H8, 1‘ ‘; 2,3-dimethyl-1,3-butadiene, C6H10, 1‘ ‘) in diethyl ether at low temperature with 2 equiv of alkylmagnesium RMgX reagents affords the corresponding dialkyl complexes CpMo(η4-1,3-diene)R2 (2, 2‘, 2‘ ‘, R = CH3, a; CH2Ph, b; CH2SiMe3, c). These species are isolable in moderate yields and have been fully characterized by EPR, elemental analyses, and cyclic voltammetry. They all show a reversible reduction process at relatively low potentials and an irreversible oxidation. The structure of 2‘ ‘a was confirmed by single-crystal X-ray diffraction. The mixed complex CpMo(η4-C4H6)Cl(CH3), …