TALP, un nou mètode de determinació d'estructures cristal·lines de fàrmacs i compostos moleculars per difracció de pols

La difracció de pols és una eina molt potent per a la determinació d'estructures cristal·lines de compostos tant iònics com moleculars quan no es disposa de monocristalls. Pel que fa als segons, les millores en els mètodes en l'espai directe dels darrers anys permeten tractar estructures cada cop més complexes malgrat les limitades resolucions espacials (dhkl) de les dades, sobretot per a molècules orgàniques. En aquest treball, es descriu i s'utilitza un nou mètode en l'espai directe, TALP, en el qual es combinen algoritmes de cerca (aleatòria o assistida amb la funció de rotació) amb afinaments per mínims quadrats ràpids de les coordenades atòmiques. Les intensitats del diagrama s'extreuen amb un procediment en tres passos i el model molecular es defineix a partir de les coordenades atòmiques, restriccions de distància i enllaços de lliure rotació. TALP ha resolt estructures amb tretze angles de torsió i amb més d'una molècula independent a la unitat asimètrica a partir de dades de difracció de pols de laboratori i utilitzant models teòrics. Com a exemple, s'explica la redeterminació pas a pas d'una estructura ja coneguda, la de l'(S)-ibuprofèn, amb TALP.Powder diffraction is a powerful tool for solving crystal structures of ionic and molecular compounds when no single crystals are available. The recent development of direct-space methods allows the resolution of complex structures of molecular compounds, despite the limited d-spacing resolution of the data for these materials and especially organic molecules. This paper describes the new direct-space multisolution method TALP and its application. It combines random or rotation function-assisted search algorithms with fast least square minimizations of atomic coordinates. Diffraction intensities are determined by a three-step procedure and the molecular model is defined in terms of atomic coordinates, distance restraints and free rotation bonds. TALP has solved structures containing thirteen torsion angles and more than one independent molecule in the asymmetric unit from laboratory powder diffraction data and calculated molecular models. By way of example, the step-by-step TALP redetermination of the known structure of (S)-ibuprofen is presented

Hollow Microcrystals of Copper Hexafluoroacetylacetonate-Pyridine Derivative Adducts via Supercritical CO2 Recrystallization

An innovative crystallization process, based in the use of the eco-friendly supercritical carbon dioxide (scCO2) solvent, is presented for the production of coordination compounds macrocrystals of general formula [Cu(hfacac)2(dPy)2], with intriguing prismatic hollow structures and single polymorphic forms. On the contrary, conventional solvents yielded compact microstructures. Studied pyridine derivatives (dPy) were 4-phenylpyridine, PhPy; 4-benzylylpyridine, BzPy; and 4-acetylpyridine, AcPy. In the specific case of the [Cu(hfacac)2(AcPy)2] adduct, the use of scCO2 as a solvent allows obtaining a pure polymorph, while the conventional solvent trials yielded a mixture of two polymorphs. Four new crystalline structures have been resolved from single crystal X-ray diffraction. All the structures consist in mononuclear complexes connected through intermolecular interactions, including H···H, H···O, F···F, C-F···Caromatic and/or C-F··· interactions, generating bidimensional networks that determine their crystallization mode in scCO2.This work was partially financed by the Spanish National Plan of Research CTQ2014-56324 and Severo Ochoa SEV-2015-0496, and by the Generalitat de Catalunya 2014SGR377. A. López-Periago acknowledges the RyC-2012-11588 contract. ALBA synchrotron is acknowledged for the provision of beamtime.Peer Reviewe

Examining the adsorption of gases into solid crystalline molecular copper(II) 3,5-bis(trifluoromethyl)benzoate derivatives

Altres ajuts: acords transformatius de la UABTwo copper(II) complexes, both involving the anionic 3,5-bis(trifluoromethyl)benzoate ligand (TFMBz), have been prepared and their structure elucidated by single crystal-X ray diffraction. [Cu(TFMBz)2(ISNA)2] (1) is a mononuclear complex, in which the sphere of coordination of Cu(II) is completed by two neutral isonicotinamide (ISNA) auxiliary ligands. Hydrogen bonding formed between auxiliary ISNA ligands determines the formation of a 2D supramolecular network. [Cu2(TFMBz)4(DMSO)2] (2) is a binuclear complex, in which the four carboxylate ligands define the typical paddle wheel structure often found in copper complexes, containing also the ancillary dimethyl sulfoxide (DMSO) ligand in axial positions. The elucidated crystallographic data provide the static view of the crystal structures, which reveals only non-interconnected voids for both materials. Even that, compound 1shows an appreciable adsorption of CO2 at 273 K (ca. 1 CO2 molecule/Cu atom at 100 kPa), concomitant with a reduced adsorption of Ar or N2 under similar conditions, which implies a considerable degree of selectivity for CO2. Moreover, 1 does not adsorb N2 or Ar at 77 K and 100 kPa. This behavior suggests that the stablished intermolecular hydrogen bonds rest flexibility and dynamism to 1 at low temperature. Contrarily, increasing the temperature transient porosity is originated, which allows guest molecules to diffuse through the cavities. Compound 2 shows adsorption of N2 and Ar at 77 K, indicating that vibrations in the network and rotation of some CF3 groups, necessary to favor adsorbate diffusion, are still feasible at this low temperature

Exploring a novel preparation method of 1D metal organic frameworks based on supercritical CO2

The preparation of copper(II) one-dimensional MOFs using an eco-efficient method is reported here. This method is based exclusively on using supercritical CO2 as a solvent, without the addition of any other additive or co-solvent. Neutral acetylacetonate copper complexes and two linear linkers, namely, the bidentate 4,4¿-bipyridine and 4,4¿-trimethylenedipyridine molecules, were reacted under compressed CO2 at 60 °C and 20 MPa for periods of 4 or 24 h. The success achieved in the synthesis of the different studied 1D-MOFs was related to the solubility of the reagents in supercritical CO2. The reaction yield of the synthesized coordination polymers via the supercritical route was close to 100% because both the reactants were almost completely depleted in the performed experiments. © The Royal Society of Chemistry 2015.This work was partially financed by EU COST project MP1202 OC-2011-2-10820 and by the Generalitat de Catalunya 2014SGR377. A. López-Periago acknowledges the RyC-2012- 11588 contract. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)Peer Reviewe

Catalan Imitations of the Ligurian Taches Noires Ware in Barcelona (18th\u201319th Century): An Example of Technical Knowledge Transfer

The ware called Taches Noires was developed in Albisola (Liguria, NW Italy) during the 18th century. In just a few years, it spread all over the Mediterranean (Italy, France, Spain, Tunisia, and Greece) and also in the New World (Canada, the Caribbean Islands, and Mexico). The success of the Taches Noires ware was so massive that it was soon copied by Spanish and French workshops. A collection of Catalan imitations and Ligurian imports found in Barcelona were analysed and compared to previously existing data from Barcelona productions, as well as reference samples from Albisola. The study proved the presence of both local imitations and original Albisola imports. The analysis showed a homogeneous product of high technical quality for the Albisola pottery. On the contrary, the local imitations presented a greater diversification in the choice and manipulation of the raw materials, probably related to the existence of different workshops engaged in the manufacturing of these products. Nevertheless, for one of the local groups, ceramists adopted a glaze recipe similar to the one used in Albisola, clearly indicating a direct transfer of knowledge, and possibly of potters, from Albisola to Barcelona

Structural study of decrespignyite-(Y), a complex yttrium rare earth copper carbonate chloride, by three-dimensional electron and synchrotron powder diffraction

The crystal structure of the mineral decrespignyite-(Y) from the Paratoo copper mine (South Australia) has been obtained by applying d recycling direct methods to 3D electron diffraction (ED) data followed by Rietveld refinements of synchrotron data. The unit cell is a = 8.5462(2), c = 22.731(2) Å and V = 1437.8(2) Å3, and the chemical formula for Z = 1 is (Y10.35REE1.43Ca0.52Cu5.31 σ17.61(CO3)14Cl2.21(OH)16.79• 18.35H2O (REE. rare earth elements). The ED data are compatible with the trigonal P 3m1 space group (no. 164) used for the structure solution (due to the disorder affecting part of the structure, the possibility of a monoclinic unit cell cannot completely be ruled out). The structure shows metal layers perpendicular to [001], with six independent positions for Y, REE and Cu (sites M1 to M4 are full, and sites M5 and M6 are partially vacant), and two other sites, Cu1 and Cu2, partially occupied by Cu. One characteristic of decrespignyite is the existence of hexanuclear (octahedral) oxo-hydroxo yttrium clusters [Y6(μ6-O)(μ3-OH)8O24] (site M1) with the 24 bridging O atoms belonging to two sets of symmetry-independent.CO3/2- ions, with the first set (2×) along a ternary axis giving rise to a layer of hexanuclear clusters and the second set (6×) tilted and connecting the hexanuclear clusters with hetero-tetranuclear ones hosting Cu, Y and REE (M2 and M3 sites). The rest of the crystal structure consists of two consecutive M3 C M4 layers containing the partially occupied M5, M6, and Cu2 sites and additional carbonate anions in between. The resulting structure model is compatible with the chemical analysis of the type material which is poorer in Cu and richer in (REE, Y) than the above-described material.Fil: Rius, Jordi. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia de los Materiales de Barcelona; EspañaFil: Colombo, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Vallcorba, Oriol. Alba Synchrotron Light Facility; EspañaFil: Torrelles, Xavier. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia de los Materiales de Barcelona; EspañaFil: Gemmi, Mauro. Istituto Italiano di Tecnologia. Center for Nanotechnology Innovation; ItaliaFil: Mugnaioli, Enrico. Istituto Italiano di Tecnologia. Center for Nanotechnology Innovation; Itali

Entrapped Transient Chloroform Solvates of Bilastine

The knowledge about the solid forms landscape of Bilastine (BL) has been extended. The crystal structures of two anhydrous forms have been determined, and the relative thermodynamic stability among the three known anhydrous polymorphs has been established. Moreover, three chloroform solvates with variable stoichiometry have been identified and characterized, showing that S3CHCl3-H2O and SCHCl3 can be classified as transient solvateswhich transforminto the newchloroform solvate SCHCl3-H2O when removed fromthemother liquor. The determination of their crystal structures from combined single crystal/synchrotron X-ray powder diffraction data has allowed the complete characterization of these solvates, being two of them heterosolvates (S3CHCl3-H2O and SCHCl3-H2O) and SCHCl3 a monosolvate. Moreover, the temperature dependent stability and interrelation pathways among the chloroform solvates and the anhydrous forms of BL have been studied

Polymorphism in secondary squaramides: on the importance of π-interactions involving the four membered ring

We report the X-ray solid state structures of four new squaric acid derivatives, i.e. three polymorphs of 3,4-bisIJ(2-(dimethylamino)ethyl)amino)cyclobut-3-ene-1,2-dione (1a-c) and a co-crystal of compound 1 and resorcinol (2). All structures form interesting supramolecular assemblies in the solid state which have been analyzed using high level DFT calculations and molecular electrostatic potential (MEP) surface calculations. A combination of H-bonding and π-π stacking interactions of the cyclobutenedione rings are crucial for the formation of the supramolecular assemblies in the solid state. Moreover, unusual antiparallel CO⋯CO interactions observed in the X-ray structure of one of the polymorphs of 1 and the lp-π interactions between one oxygen atom of resorcinol and the squaramide ring in 2 have been characterized using Bader's theory of 'atoms-in-molecules' (AIM)

One-dimensional metal-organic frameworks built by coordinating 2,4,6-tris(4-pyridyl)-1,3,5-triazine linker with copper nodes : CO2 adsorption properties

Altres ajuts: acord transformatiu CRUE-CSICThe reaction between 2,4,6-tris(4-pyridyl)-1,3,5-triazine (4-tpt) and copper(II) hexafluoroacetylacetone (Cu(hfa)2) yields two different 1D metal-organic frameworks (MOFs), [(Cu(hfa)2)2(4-tpt)]n (1) and [Cu(hfa)2(4-tpt)]n (2). The Cu:4-tpt ratio in the new MOFs is determined by the reaction medium, particularly, the solvent used. The two compounds have been fully characterized, including crystal structure elucidation. [(Cu(hfa)2)2(4-tpt)]n (1), with a 2:1 Cu:4-tpt ratio, could be precipitated in either 1,1,2-trichloroethane or supercritical CO2. In (1), 4-tpt shows a tritopic coordination mode, but only half of the Cu(hfa)2 subunits act as a node, thus connecting two 4-tpt and giving a 1D network. The other half of Cu(hfa)2 subunits are connected only to one pyridine and thus protrude along the chains. The later Cu(hfa)2 fragments show a labile character and can be dissolved in diethyl ether to give the second MOF [Cu(hfa)2(4-tpt)]n (2), with a 1:1 Cu:4-tpt ratio. The compound (2) has also a 1D structure, with all the incorporated copper atoms acting as nodes. In this case, the packing of the chains defines accessible channels, which are perpendicular to the chain axis. After activation, N2 adsorption/desorption measurements at 77 K confirm the microporous character of (2) with an apparent surface area of 190 m2 g−1. Besides, at 273 K this material clearly shows a significant adsorption of CO2 prompted by noncoordinated nitrogen in the triazine linker

Synchrotron Radiation Pair Distribution Function Analysis of Gels in Cements

The analysis of atomic ordering in a nanocrystalline phase with small particle sizes, below 5 nm, is intrinsically complicated because of the lack of long-range order. Furthermore, the presence of additional crystalline phase(s) may exacerbate the problem, as is the case in cement pastes. Here, we use the synchrotron pair distribution function (PDF) chiefly to characterize the local atomic order of the nanocrystalline phases, gels, in cement pastes. We have used a multi r-range analysis approach, where the ~4–7 nm r-range allows determining the crystalline phase contents; the ~1–2.5 nm r-range is used to characterize the atomic ordering in the nanocrystalline component; and the ~0.2–1.0 nm r-range gives insights about additional amorphous components. Specifically, we have prepared four alite pastes with variable water contents, and the analyses showed that a defective tobermorite, Ca11Si9O28(OH)2 8.5H2O, gave the best fit. Furthermore, the PDF analyses suggest that the calcium silicate hydrate gel is composed of this tobermorite and amorphous calcium hydroxide. Finally, this approach has been used to study alternative cements. The hydration of monocalcium aluminate and ye’elimite pastes yield aluminum hydroxide gels. PDF analyses show that these gels are constituted of nanocrystalline gibbsite, and the particle size can be as small as 2.5 nmThis work has been supported by Spanish MINECO through BIA2014-57658-C2-2-R, which is co-funded by FEDER, BIA2014-57658-C2-1-R and I3 (IEDI-2016-0079) grants. We also thank CELLS-ALBA (Barcelona, Spain) for providing synchrotron beam time at BL04-MSPD beamline. Finally, we thank Prof. Simon Billinge, Long Yang and Monica Dapiaggi for their help with the PDF script and simulations for Ca(OH)2 scattering dat