1-[3-(4-Nitro­phen­yl)propano­yl]urea acetic acid monosolvate

The title compound, C10H11N3O4·C2H4O2, was prepared by an electrochemical technique. In the crystal, acetic acid mol­ecules are involved in hydrogen bonding to two separate propano­ylurea mol­ecules, acting as a donor in an O—H⋯O inter­action and as an acceptor in two N—H⋯O inter­actions. The propano­ylurea mol­ecules inter­act with each other via N—H⋯O hydrogen bonds. C—H⋯O inter­actions also stabilize the crystal structure

Multiple light-induced NO linkage isomers in the dinitrosyl complex [RuCl(NO)₂(PPh₃)₂]BF₄ nravelled by photocrystallographic and IR analysis

Multiple light-induced reversible metastable NO linkage isomers (PLIs) have been detected in the dinitrosyl compound [RuCl(NO)(2)(PPh3)(2)]BF4 by a combination of photocrystallographic and IR analysis. The IR signature of three PLI states has been clearly identified, with estimated populations of 59% (PLI-1), 8% (PLI-2) and 5% (PLI-3) for a total population of the metastable state of 72%. The structural configuration of the major component (PLI-1) has been derived by X-ray photocrystallography. In the ground state, the structure is characterized by a bent and a linear nitrosyl, the bent one being oriented towards the linear equatorial nitrosyl with an Ru-N-O angle of 133.88 (9)degrees. X-ray Fourier difference maps indicate a selectivity of the photo-isomerization process in PLI-1: only the bent NO ligand changes its position, while the linear NO is unaffected. After irradiation at 405 nm, the orientation is changed by rotation towards the Cl ligand opposite the linear NO, with an Ru-N-O angle in this new position of 109 (1)degrees. The photocrystallographic analysis provides evidence that, in the photo-induced metastable state, the bent NO group is attached to the Ru atom through the N atom (Ru-N-O),rather than in an isonitrosyl Ru-O-N binding mode. In the IR spectra, the asymmetric NO vibrational band shifts by -33 cm(-1) to a lower value, whereas the symmetric band splits and shifts by 5 cm(-1) to a higher value and by -8 cm(-1) to a lower value. The down shift is a clear indication of the structural change, and the small upward shift in response to the new electronic configuration of the metastable structure. Variable-temperature IR kinetic measurements in the range 80-114 K show that the decay of the PLI-1 state follows an Arrhenius behaviour with an activation energy of 0.22 eV

Characterization of multifunctional β-NaEuF4/NaGdF4 core–shell nanoparticles with narrow size distribution

We characterized NaEuF4/NaGdF4 core–shell nanoparticles

Conducting Anilate-Based Mixed-Valence Fe(II)Fe(III) Coordination Polymer: Small-polaron Hopping Model for Oxalate-Type Fe(II)Fe(III) 2D Networks

The mixed-valence FeIIFeIII 2D coordination polymer formulated as [TAG][FeIIFeIII(ClCNAn)3]·(solvate) 1 (TAG = tris(amino)-guanidinium, ClCNAn2− = chlorocyanoanilate dianionic ligand) crystallized in the polar trigonal space group P3. In the solid-state structure, determined both at 150 and at 10 K, anionic 2D honeycomb layers [FeIIFeIII(ClCNAn)3]− establish in the ab plane, with an intralayer metal−metal distance of 7.860 Å, alternating with cationic layers of TAG. The similar Fe−O distances suggest electron delocalization and an average oxidation state of +2.5 for each Fe center. The cation imposes its C3 symmetry to the structure and engages in intermolecular N−H···Cl hydrogen bonding with the ligand. Magnetic susceptibility characterization indicates magnetic ordering below 4 K and the presence of a hysteresis loop at 2 K with a coercive field of 60 Oe. Mössbauer measurements are in agreement with the existence of Fe(+2.5) ions at RT and statistic charge localization at 10 K. The compound shows semiconducting behavior with the in-plane conductivity of 2 × 10−3 S/cm, 3 orders of magnitude higher than the perpendicular one. A small-polaron hopping model has been applied to a series of oxalate-type FeIIFeIII 2D coordination polymers, providing a clear explanation on the much higher conductivity of the anilate-based systems than the oxalate ones

Cristallographie à haute résolution des complexes acides minéraux bases azotées ou acides aminés : Etude des interactions intermoléculaires

Organic-inorganic hybrid materials resulting from the association of amino acids with phosphorous acid have a great importance in industry: IR, very high SGH, and NLO properties make these hybrid materials highly attractive for frequency doubling, they also can be used as infrared detectors and pyroelectric devices). We report in the first part of this work chemical preparation, infrared and NMR spectroscopic studies and structural determination by single crystal X-ray diffraction of six new hybrid complexes. The second part is devoted to an accurate analysis of the reversible first order single crystal phase transition that occurs in m-CPAMP. The thermal behaviour and the study of charge density of m-CPAMP using high-resolution data sets collected with synchrotron and neutron diffraction experiments at low temperature will be presented and discussed. This study allows a better understanding of the phase transition mechanism.Les matériaux hybrides "organique-inorganique" sont l'objet d'un intérêt immense, en permettant d'allier à la fois certaines propriétés d'un matériau inorganique (ou d'une molécule), et certaines propriétés d'un polymère (ou d'une molécule organique). Les applications de ces matériaux "nouveaux" couvrent des champs aussi variés que les propriétés de résistance mécanique, l'optique, l'électronique et l'ionique du solide et les biomatériaux. Notre étude porte sur les complexes hybrides constitués de groupements phosphite (ou phosphate) comme anions minéraux et d acides aminés ou de bases azotées comme matrices organiques. La première partie de ce travail est consacrée à la caractérisation spectroscopique ainsi que l étude structurale de six nouveaux composés hybrides à base de phosphate et de phosphite. Nous présentons dans la deuxième partie une étude très détaillée de la transition de phase réversible de premier ordre avec effet d hystérésis présente dans le composé m-CPMAP. La discussion du comportement des divers groupements autour de la transition est suivie par une analyse haute résolution de la densité électronique dans la phase basse température à partir de données synchrotron, combinée à une analyse neutronique

Cristallographie à haute résolution des complexes acides minéraux bases azotées ou acides aminés (Etude des interactions intermoléculaires)

Les matériaux hybrides "organique-inorganique" sont l'objet d'un intérêt immense, en permettant d'allier à la fois certaines propriétés d'un matériau inorganique (ou d'une molécule), et certaines propriétés d'un polymère (ou d'une molécule organique). Les applications de ces matériaux "nouveaux" couvrent des champs aussi variés que les propriétés de résistance mécanique, l'optique, l'électronique et l'ionique du solide et les biomatériaux. Notre étude porte sur les complexes hybrides constitués de groupements phosphite (ou phosphate) comme anions minéraux et d acides aminés ou de bases azotées comme matrices organiques. La première partie de ce travail est consacrée à la caractérisation spectroscopique ainsi que l étude structurale de six nouveaux composés hybrides à base de phosphate et de phosphite. Nous présentons dans la deuxième partie une étude très détaillée de la transition de phase réversible de premier ordre avec effet d hystérésis présente dans le composé m-CPMAP. La discussion du comportement des divers groupements autour de la transition est suivie par une analyse haute résolution de la densité électronique dans la phase basse température à partir de données synchrotron, combinée à une analyse neutronique.Organic-inorganic hybrid materials resulting from the association of amino acids with phosphorous acid have a great importance in industry: IR, very high SGH, and NLO properties make these hybrid materials highly attractive for frequency doubling, they also can be used as infrared detectors and pyroelectric devices). We report in the first part of this work chemical preparation, infrared and NMR spectroscopic studies and structural determination by single crystal X-ray diffraction of six new hybrid complexes. The second part is devoted to an accurate analysis of the reversible first order single crystal phase transition that occurs in m-CPAMP. The thermal behaviour and the study of charge density of m-CPAMP using high-resolution data sets collected with synchrotron and neutron diffraction experiments at low temperature will be presented and discussed. This study allows a better understanding of the phase transition mechanism.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

Multiscale study of the influence of the structural changes on the optical properties of photoactive complexes confined in mesoporous matrices

Les matériaux poreux silicatés ont été mis à profit pour encapsuler différents types de molécules, clusters ou nano-objets fonctionnels, donnant lieu à des nanocomposites hybrides organiques-inorganiques à propriétés physiques, chimiques ou biologiques remarquables. Élucider l'organisation structurale à l'échelle moléculaire de tels nanocomposites est indispensable pour l'analyse et la compréhension des propriétés macroscopiques qui en découlent. Ainsi, les techniques de diffusion totale associées à la fois à l'analyse Debye et la Fonction de Distribution de Paires (PDF) sont des méthodes de choix pour la caractérisation des propriétés structurales de matériaux hybrides nano-structurés. Le principal objectif de ce travail consiste à l'utilisation des approches basées sur la diffusion totale de rayons X pour l'analyse structurale complète de molécules photoactives confinées dans des matrices silicatées amorphes avec différentes tailles de pores, afin d'étudier l'influence de l'organisation structurale sur les propriétés optiques et d'explorer également les limites de ces approches d'analyse. Nous avons étudié deux systèmes photoactifs. L'analyse structurale du premier complexe confiné, Na2[Fe(CN)5NO].2H2O (SNP), a été entreprise par une approche multi-échelle combinant la RMN du solide et l'analyse PDF. Cette approche a permis l'identification de la nature des espèces incorporées, l'arrangement des cations et des anions ainsi que la distinction des différentes phases existantes : molécules isolées et nanoparticules. Les analyses Debye et PDF sur le deuxième composé étudié, [NdCl2(H2O)6]Cl, montrent que l'organisation structurale du complexe confiné est différente de celle du matériau massif cristallin. De plus, les cations Nd3+ changent de coordination de 8 à 9 durant le processus d'imprégnation et adoptent ainsi un arrangement structural très similaire à celui en solution aqueuse. Cette modification structurale est en accord avec le changement des propriétés luminescentes de ce complexeSilica xerogels are versatile host materials for the inclusion of molecules, clusters, or nano-objects yielding host-guest compounds with unique physical, chemical or biological properties. The knowledge of the structural organization of the guest within the host is crucial for the understanding of its properties. Total scattering methods, based on Debye function analysis (DFA) and Pair Distribution Function (PDF), have become powerful tools for structural characterization of nanostructured hybrid materials. The aim of this work is to use the X-ray total scattering method to obtain structural information on photoactive molecules embedded into amorphous silica hosts with different pore sizes, to correlate their structure with the optical properties, and to explore the limitations of the chosen method. Two different photoactive complexes have been investigated. In the first example, the combined PDF and NMR study on Na2[Fe(CN)5NO].2H2O (SNP) embedded into silica matrices allows to extract the nature of the inserted species: quasi-free isolated molecules can be distinguished from nanoparticles and in the former case a model for the arrangement of cation-anion can be proposed from the PDF analysis. In the second example, a luminescent Nd3+ complex, the PDF and DFA analysis reveal that the structural organization of the embedded Nd3+ complexes is different from that of the crystalline material. Furthermore, the Nd3+ cations change the coordination from 8 to 9 during the wet-impregnation doping and adopt very similar structural arrangement as in aqueous solution, which is in agreement with the observed change in the luminescence propertiesMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

A comparative study of two polymorphs of L-aspartic acid hydrochloride

International audienceTwo polymorphs of l-aspartic acid hydrochloride, C4H8NO4+center dot Cl-, were obtained from the same aqueous solution. Their crystal structures have been determined from single-crystal data collected at 100 K. The crystal structures revealed three-and two-dimensional hydrogen-bonding networks for the triclinic and orthorhombic polymorphs, respectively. The cations and anions are connected to one another via N-H center dot center dot center dot Cl and O-H center dot center dot center dot Cl interactions and form alternating cation-anion layer-like structures. The two polymorphs share common structural features; however, the conformations of the l-aspartate cations and the crystal packings are different. Furthermore, the molecular packing of the orthorhombic polymorph contains more interesting interactions which seems to be a favourable factor for more efficient charge transfer within the crystal

Structure and dynamics of guest molecules confined in a mesoporous silica matrix: Complementary NMR and PDF characterisation

International audienceWe present an experimental approach to study the structure and dynamics of molecular functional complexes in porous host matrices. Combining the results of Solid-State NMR and pair distribution function analysis based on total X-ray scattering data the structural arrangement and dynamical behaviour of Na-2[Fe(CN)(5)NO]center dot 2H(2)O (SNP) embedded in amorphous SiO2 matrix is investigated. We show that the SNP complexes are embedded as isolated complexes within the SiO2 pores and propose a structural model for the cation and anion arrangement. Additionally the NMR results demonstrate the rotational dynamics of the SNP complexes