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A series of lead(II) complexes incorporating benzoate derivative ligands was prepared: [Pb(2MeOBz)2]n (1), [Pb(2MeOBz)2(H2O)]n (2), [Pb2(1,4Bzdiox)4(DMSO)]n (3), [Pb(1,4Bzdiox)2(H2O)]n (4), [Pb(Pip)2(H2O)]n (5), and [Pb(Ac)(Pip)2(MeOH)]n (6) (2MeOBz: 2-methoxybenzoate; 1,4Bzdiox: 1,4-benzodioxan-5-carboxylate; DMSO: dimethylsulfoxide; Ac: acetate; Pip: piperonylate; MeOH: methanol). All compounds were characterized via elemental analysis, ATR-FTIR spectroscopy, and powder XRD. In addition, the crystal structures of some compounds were elucidated. Compounds 1 and 2, involving 2-methoxybenzoate, were closely related, only differing in the presence of one extra aqua ligand found for the latter. However, this implies key changes in the studied properties, e.g., 2 shows solid-state luminescence that displays a different color as a function of the crystal orientation, while 1 does not. The crystal structure of 2 revealed a 1D coordination polymer. A similar relationship was found between compounds 3 and 4, incorporating 1,4-benzodioxan-5-carboxylate. In this pair, only 4, with aqua ligands, displayed a greenish-yellow-color solid-state luminescence. Furthermore, two new lead(II) piperonylate complexes, 5 and 6, were obtained from the reaction between lead(II) acetate and piperonylic acid. In water, all acetate ligands in the metal precursor were displaced and [Pb(Pip)2(H2O)]n (5) was isolated, while in methanol, a mixed acetate–piperonylate complex, [Pb(Ac)(Pip)2(MeOH)]n (6), was precipitated. Considering only conventional Pb-O bonds, the crystal structure of 6 was described as a 1D coordination polymer, although, additionally, the chains were associated via tetrel bonds, defining an extended 2D architecture.

A facile, fast and green strategy based on ethanol is utilized to prepare a new bioMOF, namely, CaSyr-1, with particular characteristics of full biocompatibility given by using just calcium and syringic acid, the latter being a phenolic natural product found in fruits and vegetables, permanent porosity with an outstanding surface area >1000 m2 g−1, and a micropore diameter of 1.4 nm close to mesopore values. Collectively, these data establish CaSyr-1 as one of the most porous bioMOFs reported to date, with high molecular adsorption capacity. The CaSyr-1 adsorptive behavior is revised here through the reversible adsorption of CO2 and the encapsulation of bioactive ingredients in the structure. Remarkably, CaSyr-1 enables the development of triple therapeutic entities, involving bioactive Ca2+, syringic acid and an impregnated drug.

Two 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 1 shows 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.

The 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.

This paper provides a detailed technological characterization of the Roman opus sectile glasses (second century AD) coming from the renowned Gorga collection. Nine glass samples corresponding to imitations of the porfido verde antico, cipollino rosso, rosso antico, giallo antico, diaspro nero e giallo, semesanto and agate/alabaster stones were studied. The aim of this study was twofold: (i) archaeometric, i.e., to provide valuable data on the production, raw materials and techniques of these refined Roman glasses that mimic precious stones and (ii) methodological, i.e., to highlight the good performance of combining polished thin sections and local probe measurements for the study of glassy microstructures. Based on the nature of the flux used, the glasses from the samples were classified as either natron-type or mixed-type (natron/plant ash). The latter stem from remelted glasses and contain relict grains of wollastonite that were not found in the pure natron samples. Relict wollastonite crystals appear to be a proficient petrographic marker to spot recycled glasses along with the commonly used chemical fingerprints. Different production and colouring techniques were identified, even for a given type of imitated stone. Metallic Cu, Ca antimonates and Pb-Fe antimonates were the three opacifiers used for the opaque glasses. Based on the crystal morphologies, metallic Cu and Ca antimoniates were possibly synthesized in situ simultaneously with the glass, whilst the Pb-Fe antimonates were prepared ex situ. The working temperatures for these glasses were estimated within the 900–1100 °C range based on the presence and known thermal stability of some identified crystal phases.

This paper provides a detailed technological characterization of the Roman opus sectile glasses (second century AD) coming from the renowned Gorga collection. Nine glass samples corresponding to imitations of the porfido verde antico, cipollino rosso, rosso antico, giallo antico, diaspro nero e giallo, semesanto and agate/alabaster stones were studied. The aim of this study was twofold: (i) archaeometric, i.e., to provide valuable data on the production, raw materials and techniques of these refined Roman glasses that mimic precious stones and (ii) methodological, i.e., to highlight the good performance of combining polished thin sections and local probe measurements for the study of glassy microstructures. Based on the nature of the flux used, the glasses from the samples were classified as either natron-type or mixed-type (natron/plant ash). The latter stem from remelted glasses and contain relict grains of wollastonite that were not found in the pure natron samples. Relict wollastonite crystals appear to be a proficient petrographic marker to spot recycled glasses along with the commonly used chemical fingerprints. Different production and colouring techniques were identified, even for a given type of imitated stone. Metallic Cu, Ca antimonates and Pb-Fe antimonates were the three opacifiers used for the opaque glasses. Based on the crystal morphologies, metallic Cu and Ca antimoniates were possibly synthesized in situ simultaneously with the glass, whilst the Pb-Fe antimonates were prepared ex situ. The working temperatures for these glasses were estimated within the 900–1100 °C range based on the presence and known thermal stability of some identified crystal phases.

Herein we explore the opportunities arising from combining bicyclic amine cations with halometallate anions to build organic–inorganic hybrid materials. We will use the crystal engineering approach in these materials, focusing on the tuning of the organic cation, which is mainly responsible for obtaining both new plastic states at high temperature and electrical behaviour below the plastic temperature. Precisely, this work explores the influence of the ketonization of the bicyclic quinuclidine molecule (C7H13N)+, which, combined with the tetrachloroferrate(1-) anion, gives the compound (3-oxoquinuclidinium)[FeCl4]. Interestingly, crystallization in the presence of humidity is enough to obtain an isostructural hydrate phase of formula (3-oxoquinuclidinium)[FeCl4]·H2O. Although the organic–inorganic layered structure is the same in both compounds, the three-dimensional magnetic ordering disappears after the intercalation of crystallization water molecules. A heat treatment above 400 K allows the removal of water obtaining the non-hydrate phase. Finally, the temperature evolution of the electric and magnetic behaviour will be compared with other previously reported hybrid organic–inorganic materials built with tetrachloroferrate ions and quinuclidinium-based cations.

The reaction of [Co2(H2O)(TFMBz)4(py)4] (1) (TFMBz: 3,5-bis(trifluoromethyl)benzoate; py: pyridine) with 4,4'-bipyridine (bpy) in different solvents yields four coordination polymers with unlikely structures but with the same stoichiometry. Three of them contain similar ladder chains consisting of binuclear nodes "Co2(TFMBz)4", in which two of the TFMBz ligands show bidentate bridge coordination, double linked to each adjacent node by bpy but packed in different fashions. The different packing affects the compound porosity; thus, [Co2(TFMBz)4(bpy)2]n (2), precipitated using low-polarity solvents such as supercritical CO2 (scCO2), n-butyl acetate, or heptane and also in acetonitrile, is microporous, with a surface area of 330 m2 g-1, showing the N2 adsorption/desorption isotherm at 77 K with a gate-opening effect at low relative pressures (P/P0 = 0.05). The isomer [Co2(TFMBz)4(bpy)2]n (3), synthesized in ethoxyethanol, presents a surface area of 230 m2 g-1. A third chain packing isomer, [Co2(TFMBz)4(bpy)2]n (4), is obtained in acetone and has only non-interconnected voids. Finally, precursor 1 is combined with bpy in a highly polar solvent such as water to give [Co(TFMBz)2(bpy)]n (5). In this isomer, all the carboxylate units act as bidentate bridging ligands, generating chains that are interlinked by bpy, leading to a 2D network, which after packing yields a non-porous structure. The resolution of structures 2-5 is only possible with the recently developed 3D electron diffraction method based on the collection of diffraction patterns on sub-micron-sized single crystals. The variation of magnetic susceptibility as a function of temperature is also measured. Overall, our work provides insightful information on the complex landscape of metal-organic framework solids that are formed by crystallization using different solvent media.

A High Temperature Synchrotron Radiation X-Ray Powder Diffraction experiment was performed to determine the manganese compounds formed during the heating and cooling of 70 wt% PbO – 30 wt% SiO2 mixture or the equivalent glass plus 10 wt% of MnO. The effect of adding calcite, dolomite and kaolinite were also studied. All mixtures were fired between 690 ¿C and 1020 ¿C in oxidizing conditions and analysed by Scanning Electron Microscopy. A sequence of manganese phases are formed during firing: bixbyite (Mn2O3), barysilite ((Pb,Mn)Si2O7), kentrolite (Pb2Mn2Si2O9) and braunite (Mn7SiO12). Kentrolite and braunite crystallise with different crystal habits during the heating and the cooling. If dolomite is present diopside ((Ca,Mg,Mn)2Si2O6) is formed. If calcite is present, ganomalite (Pb3(CaMn)2Si3O11), margarosanite (Pb(Ca,Mn)2Si3O9) and wollastonite ((Ca,Mn)SiO3) are also formed. Wollastonite can incorporate enough manganese to transform into bustamite ((Mn,Ca)3Si3O9) at high temperatures. This leaves less manganese available for the crystallisation of kentrolite and braunite., Peer Reviewed, Postprint (author's final draft)

The reaction of [Co2(H2O)(TFMBz)4(py)4] (1) (TFMBz: 3,5-bis(trifluoromethyl)benzoate; py: pyridine) with 4,4′-bipyridine (bpy) in different solvents yields four coordination polymers with unlikely structures but with the same stoichiometry. Three of them contain similar ladder chains consisting of binuclear nodes "Co2(TFMBz)4", in which two of the TFMBz ligands show bidentate bridge coordination, double linked to each adjacent node by bpy but packed in different fashions. The different packing affects the compound porosity; thus, [Co2(TFMBz)4(bpy)2]n(2), precipitated using low-polarity solvents such as supercritical CO2(scCO2), n-butyl acetate, or heptane and also in acetonitrile, is microporous, with a surface area of 330 m2g-1, showing the N2adsorption/desorption isotherm at 77 K with a gate-opening effect at low relative pressures (P/P0= 0.05). The isomer [Co2(TFMBz)4(bpy)2]n(3), synthesized in ethoxyethanol, presents a surface area of 230 m2g-1. A third chain packing isomer, [Co2(TFMBz)4(bpy)2]n(4), is obtained in acetone and has only non-interconnected voids. Finally, precursor 1 is combined with bpy in a highly polar solvent such as water to give [Co(TFMBz)2(bpy)]n(5). In this isomer, all the carboxylate units act as bidentate bridging ligands, generating chains that are interlinked by bpy, leading to a 2D network, which after packing yields a non-porous structure. The resolution of structures 2-5 is only possible with the recently developed 3D electron diffraction method based on the collection of diffraction patterns on sub-micron-sized single crystals. The variation of magnetic susceptibility as a function of temperature is also measured. Overall, our work provides insightful information on the complex landscape of metal-organic framework solids that are formed by crystallization using different solvent media.

Different iron oxide catalysts supported on mesoporous silica were prepared by several techniques including assembly of pre-synthesized nanoparticles, coprecipitation in the presence of the support or impregnation. Characterization showed that iron oxide nanoparticles were dispersed either at the surface of the SiO2 material or within the pores when prepared by dry impregnation. The catalytic performance of these materials for Fenton chemistry was evaluated through kinetic tests in the presence of coumarin as a radical trap for the quantification of the HO˙ radicals produced. The first tests concerned the production of HO˙ radicals from H2O2 by a Fenton-like reaction. The results show that catalysts prepared by dry impregnation in an ethanolic solution show the highest activity toward the production of HO˙ radicals. These catalysts were also engaged in a reaction without external H2O2 using a cold atmospheric pressure plasma jet treatment with the successful purpose of increasing the production of HO˙ radicals in aqueous solution at room temperature and near-neutral pH. Our best catalysts outperformed others reported in the literature in reactions carried out with soluble species or at acidic pH. Moreover, a synergetic effect between the heterogeneous catalyst and the plasma for HO˙ radical production was highlighted. These radicals could be easily used for biomedical or wastewater treatment applications.

The ammonium salt of monoethyloxalate (AmEtOx) was investigated as a novel precursor for the conservation of carbonate stone substrates, such as biomicritic limestone and marble. Full characterization of treated and untreated authentic stone samples was carried out by means of SEM, X-ray powder diffraction, synchrotron tts-µXRD measurements, mercury intrusion porosimetry, determination of water transport properties, and pull-off tests. The improved solubility (1.49 M, 20.1% w/w) of AmEtOx as compared to that of ammonium oxalate (AmOx; 0.4 M, 5% w/w) results in the formation of microcrystalline phases 30–50 and 200–500 µm thick of calcium oxalate mono-(whewellite) or dihydrate (weddellite), on marble and biomicrite samples, respectively, after treatment with AmEtOx 5% and 12% w/w aqueous solutions. As a result, a reduction in the porosity of the stone samples and an enhancement of their cohesion are observed. DFT calculations, carried out to investigate the hydrolysis reaction leading from AmEtOx to AmOx, showed that the localization of the Lowest Unoccupied Molecular Orbital (LUMO) and the natural charge distribution account nicely for the tendency to hydrolyse observed experimentally, eventually leading to the formation of whewellite and weddellite on the stone surface., Peer Reviewed, Preprint

The materials, painting techniques and conservation state of the enamelled stain glass of the Catalan Modernist workshops operating in Barcelona are studied. It is known for its creativity and artistic value where textured, flashed, coloured and enamelled glasses concur. In the late 19th century, Catalan workshops used a new type of ready-to-be-used enamels (lead-zinc borosilicate glass) incorporating pigment particles and colourants. Although humidity, pollutants and solar irradiation are the main causes of corrosion, the microstructure of the enamels plays a role- Enamels that contain large particles close to the surface appear more corroded than those that are fully amorphous. Lixiviation of lead, boron and zinc produced a hydrated layered silica rich fragile glass and the subsequent precipitation of lead, sodium and calcium compounds on the surface, cracks around particles and inside the bubbles decrease the chemical and mechanical stability. The practices of some workshops produced enamels with reduced stability., Peer Reviewed, Postprint (author's final draft)

Cobalt was used since the early antiquity to tinge glass and glazes in blue. The presence of arsenic in blue decorated glazes since ~1500 onwards and absence beforehand, observed in Europe, might be related to the processing of the ore: roasting of the cobalt mineral (saffre) and obtaining a glass adding sand and potash (smalt) or as by-product of other metallurgical processes, e.g. silver smelting slag. We have replicated the roasting of cobalt arsenide ore (CoAs3) and the processing of silver smelting as described in historical treatises following the transformations by in situ variable temperature SR-XRD, PIXE and SEM. Our laboratory tests have proved that roasting cobalt arsenide ore either alone or mixed with fluxes (PbO, CaF2), CaCO3, SiO2 and kaolinite was unable to remove the arsenic completely. Roasting cobalt arsenide ore (saffre) alone explains the presence of arsenic in the cobalt blue glasses and glazes after 1520. The product obtained as described by Agricola contains less arsenic forming calcium arsenates, lead arsenates (Pb5(AsO4)3F, Pb8As2O13) and calcium lead arsenates (Ca,Pb)5(A-sO4)3(F,Cl,OH) with an hedyphane structure, while cobalt is incorporated into a glassy matrix. As the physical separation of the arsenic free cobalt vitreous phase does not seem possible, these processes can explain the variable content of arsenic shown by the historical blue glazes but not the arsenic free glazes. In this case, the use of an arsenic free cobalt ore such as linnaeite is the most likely source., Peer Reviewed, Postprint (author's final draft)

Quinuclidinium salts and their derivatives are now in the focus of materials science as building units of multifunctional materials. Their properties can be easily switchable, allowing their use in a wide range of physical applications. One type of these kinds of materials, the homochiral hybrid halometallate ferroelectric compounds, is not well understood. In this work, (R)-(-)-3-quinuclidinol hydrochloride was used in the synthesis of ((R)-(-)-3-hydroxyquinuclidium)[FeCl4]. The use of this enantiomeric cation forces crystallographic non-centrosymmetry, which was confirmed by polarimetry and circular dichroism spectroscopy. We studied the physical properties of this compound at different temperatures by single crystal, synchrotron and neutron powder X-ray diffraction, which showed a rich series of structural and magnetic phase transitions. From synchrotron powder X-ray diffraction data, a plastic phase was observed above 370 K (phase I). Between 370 K and ca. 310 K, an intermediate polar phase was detected, solved in a non-centrosymmetric polar space group (C2) (phase II). Below ca. 310 K, the compound crystallizes in the triclinic P1 non-centrosymmetric space group (phase III) which is maintained down to 4 K, followed by phase IV, which shows tridimensional magnetic ordering. The temperature evolution of the neutron diffraction data shows the appearance of new reflections below 4 K. These reflections can be indexed to a commensurate propagation vector k = (0, 0, ½). The magnetic structure below TN was solved in the Ps1 Shubnikov space group, which gives rise to an antiferromagnetic structure, compatible with the magnetometry measurements. Near room temperature, the crystal phase transition is associated with a dielectric change. In particular, the phase transition between phase III (S.G.:P1) and phase II (S.G.:C2) involves an increase of symmetry between two non-centrosymmetric space groups. Therefore, it allows, by symmetry, the emergence of ferroelectric and fer, Postprint (author's final draft)

Soft crystallization routes for the controlled growth of oneand two-dimensional Cu(II)-coordination polymers of the type [(Cu- (hfa)2)x(3-tpt)]n (hfa = hexafluoroacetylacetonate, 3-tpt = 2,4,6-tris(3- pyridyl)-1,3,5-triazine) are described. Three volatile solvents with different protic/aprotic characteristics were chosen as the reaction media, e.g., supercritical CO2, chloroform, and ethanol. Five (1−5) new compounds were crystallized, with different structures and Cu(II)/3-tpt ratios. The structures of 3-tpt and five new coordination polymers were elucidated by single-crystal synchrotron X-ray diffraction. A description of the crystallization pathways followed for the synthesis of the individual compounds is given based on the protic or aprotic character of the used solvents and reagents’ solubility constraints. The main novelty of the work relies in establishing the foundations of 3-tpt isomeric control during crystallization through solvent selection. From the five precipitated new compounds, 3 displays a significant framework flexibility, associated with N2 adsorption at low temperature, presenting a stepwise adsorption isotherm. The N2 adsorption process was followed by in situ synchrotron X-ray powder diffraction

The synthesis of 1D cobalt and zinc monometallic and heterometallic coordination polymers (CPs) was carried out applying one-pot synthetic methods by using either supercritical carbon dioxide or ethanol as the solvent. A collection of four 1D CPs were thus obtained by the combination of a metal (or a mixture of metals) with the linker 1,4-bis(4-pyridylmethyl)benzene. The used metallic complexes were zinc and cobalt hexafluoroacetylacetonate, which can easily incorporate pyridine ligands in the coordination sphere of the metal centre. Independently of the used solvent, the precipitated phases involving Zn(II), i.e., homometallic CP of Zn(II) and bimetallic CP of Zn(II)/Co(II), were isostructural. Contrarily, homometallic CPs of Co(II) were precipitated as an isostructural phase of Zn(II) or with a different structure, depending on the used solvent. All the structures were resolved by XRD using synchrotron radiation. In addition, the magnetic properties of the new CPs involving Co(II) were studied. Remarkably, at low temperatures with the application of an external field, they acted as field-induced single molecule magnets.

The d1Dplot and d2Dplot computer programs have been developed as user-friendly tools for the inspection and processing of 1D and 2D X-ray diffraction (XRD) data, respectively. d1Dplot provides general tools for data processing and includes the ability to generate comprehensive 2D plots of multiple patterns to easily follow transformation processes. d2Dplot is a full package for 2D XRD data. Besides general processing tools, it includes specific data analysis routines for the application of the through-the-substrate methodology [Rius et al. IUCrJ 2015, 2, 452–463]. Both programs allow the creation of a user compound database for the identification of crystalline phases. The software can be downloaded from the ALBA Synchrotron Light Source website and can be used free of charge for non-commercial and academic purposes.

Among metamagnetic materials, FeRh alloys are technologically appealing due to their uncommon antiferromagnetic-to-ferromagnetic metamagnetic transition which occurs at a temperature T* just above room temperature. Here, a controlled increase of T* (DT* B 20 8C) is induced in pre-selected regions of FeRh films via mechanical strain nanopatterning. Compressive stresses generated at the vicinity of predefined nanoindentation imprints cause a local reduction of the FeRh crystallographic unit cell parameter, which leads to an increase of T* in these confined micro-/nanometric areas. This enhances the stability of the antiferromagnetic phase in these localized regions. Remarkably, generation of periodic arrays of nanopatterned features also allows modifying the overall magnetic and electric transport properties across large areas of the FeRh films. This approach is highly appealing for the design of new memory architectures or other AFM-spintronic devices.

Coloured enamels from the materials used in Modernist workshops from Barcelona were produced and compared to those found in the buildings to explore the reason for the reduced stability of the blue and green enamels. They were made of a lead-zinc borosilicate glass with a low softening point, reasonable stability to corrosion and matching thermal expansion coefficient with the blown base glass, mixed with colourants and pigment particles. The historical enamels show a lead, boron and zinc depleted silica rich amorphous glass, with precipitated lead and calcium sulphates or carbonates, characteristic of extensive atmospheric corrosion. The blue and green enamels show a heterogeneous layered microstructure more prone to degradation which is augmented by a greater heating and thermal stress affectation produced by the enhanced Infrared absorbance of blue tetrahedral cobalt colour centres and copper ions dissolved in the glass and, in particular, of the cobalt spinel particles., Peer Reviewed, Postprint (author's final draft)

Nowadays, there is a great interest in the design of new metal–organic frameworks (MOFs) synthetized by routes that can be transferred to industrial scale with low environmental impact. In this context, this work explores the use of a soft method for the synthesis of MOFs, in which neat acetic acid is used as the reaction media. Trimesic acid (H3BTC) was chosen as the organic linker source and combined with different metal acetates, all these precursor being moderately soluble in hot acetic acid. The metal acetate provides both the metallic cation and a base, the acetate, necessary to deprotonate the H3BTC. Three first row transition metals, Cu, Co and Ni, and one heavy metal, Bi, were chosen for the study. Results denoted that the metal acetate was determinant to direct the nature of the precipitated material. For instance, the precipitation of the well-known porous HKUST-1 was observed from Cu acetate and H3BTC in neat acetic acid, giving systems with hierarchical porosity. Contrarily, for Co and Bi the use of acetic acid as a solvent yielded two 2D non porous coordination polymers, [Co6(BTC)2(Ac)6(HAc)3] (1) and [Bi(HBTC)(Ac)] (3), respectively. These new compounds were structurally elucidated. Moreover, the magnetic behaviour was analysed for the Co compound (1). Finally, an amorphous phase was precipitated for Ni. In the latter case, the use of propionic acid, with a higher boiling point than acetic acid, led to the precipitation of a crystalline material.

The d2Dplot computer program provides a set of tools for the visualization, processing and analysis of 2D X-ray diffraction (2DXRD) data. Among the operations available there are the sum/subtraction of 2DXRD images, conversion to 1D data (powder pattern), azimuthal plotting, calibration of instrumental parameters, background subtraction and a command-line mode to run operations inside data processing pipelines. The graphical user interface allows easy use of the program. It also includes two main features: (i) the possibility of creating a user compound database to help in the fast phase identification of similar samples, and (ii) a detailed peak analysis routine for the application of the through-the-substrate microdiffraction methodology.

This paper presents the characterization of the intermetallic phases of laser-welded Al-Cu joints by synchrotron trough-the-substrate microdiffraction combined with SEM/EDX and etched/non-etched optical micrographs. Transmission microdiffraction offers the spatial resolution and beam flux necessary to study the intermetallic phases, which in conjunction with the excellent contrast of etched micrographs, rendered possible the phase identification. It was found that the major phases are Al2Cu (θ), Al4Cu9 (γ1) and AlCu (η2) were formed. The Al3Cu4 (ζ1) and δ phases where formed in less amount and found to be the primary cause for cracks inside the weld seam and therefore for the failure of the joint.

This paper presents the characterization of the intermetallic phases of laser-welded Al-Cu joints by synchrotron trough-the-substrate microdiffraction combined with SEM/EDX and etched/non-etched optical micrographs. Transmission microdiffraction offers the spatial resolution and beam flux necessary to study the intermetallic phases, which in conjunction with the excellent contrast of etched micrographs, rendered possible the phase identification. It was found that the major phases are Al2Cu (θ), Al4Cu9 (γ1) and AlCu (η2) were formed. The Al3Cu4 (ζ1) and δ phases where formed in less amount and found to be the primary cause for cracks inside the weld seam and therefore for the failure of the joint.

The characterization of the crystal structure, phase transitions, magnetic structure and dielectric properties has been carried out on [CH3 NH3 ][Co(COOH)3 ] (1) perovskite-like metal-organic compound through variable-temperature single-crystal and powder neutron and X-ray diffraction and relative permittivity measurements. The paraelectric to antiferroelectric-like phase transition observed at around 90 K is triggered by a structural phase transition; the structural studies show a change from Pnma space group at RT (1A) to P21 /n space group at low temperature (1B). This phase transition involves the occurrence of small distortions in the framework and counterions. Neutron diffraction studies have shown a magnetic order showing spontaneous magnetization below 15 K, due to the occurrence of a non-collinear antiferromagnetic structure with a weak ferromagnetic component, mainly due to the single-ion anisotropy of the CoII ions.

"This is the peer reviewed version of the following article: Di Febo, R., Molera, J., Pradell, T., Melgarejo, J.C., Madrenas, J., Vallcorba, O. The production of a lead glaze with galena: Thermal transformations in the PbS-SiO2 system. "Journal of the American Ceramic Society", 4 Desembre 2017., which has been published in final form at https://onlinelibrary.wiley.com/doi/abs/10.1111/jace.15346. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.", Galena, also known as PbS, was widely used in the production of lead glazes from the beginning of the 18th century to the second half of the 20th century. Although the PbO-SiO2 system has been studied for years, the PbS-SiO2 phase diagram, involved in the formation of a glaze with galena, has not yet been investigated. Temperature transformations for the system 75 wt% PbS-25 wt% SiO2 are investigated in a high-temperature resolved X-ray diffraction experiment with synchrotron radiation and compared to those of the equivalent system 70 wt% PbO-30 wt% SiO2. Lanarkite, PbO·PbSO4, is the phase predominantly formed as soon as galena decomposes during the heating. The results show that the system melts at a temperature higher than the PbO-SiO2 system, but far lower than those expected for the PbO-PbSO4-PbS system. A historical misfired lead glaze produced with galena is also studied. The presence of galena, lanarkite, and mattheddleite, Pb10(SiO4)3.5(SO4)2Cl2, is determined and discussed in terms of the composition of the galena mineral used and the firing conditions in light of the high-temperature transformations previously obtained., Peer Reviewed, Postprint (author's final draft)

This is the author's pre-print for the publicaction. The published version can be found at: https://doi.org/10.1127/ejm/2017/0029-2638, The Mn-and Fe-rich micro-crystalline precipitates formed in the decorations of lead glazes during ceramic firing are responsible for colour, shine and opacity, among other visual characteristics, besides being the most important relics of the technology. Due to their small size and growth habits, the micro-crystalline precipitates may remain unidentified on polished cross sections of the glazes. Thin-section petrography, combined with synchrotron-radiation X-ray micro-diffraction, appears to be a very powerful tool to reveal the presence, growth habits, distribution and nature of the micro-crystallites. This is illustrated here by two case studies directly related to the brown decorations technology: the 19th century French imitations of the Ligurian Taches Noires pottery from the Joques workshop and the 17th century Catalan-decorated tablewares. Melanotekite, cristobalite and hematite micro-crystallites were found in the glazes of the French imitations. Hematite acted as nucleating agent effective in promoting both the crystallization of melanotekite and cristobalite. The presence of cristobalite is not related to alkali ions, which are normally responsible for its formation far from equilibrium conditions. Melanotekite and cristobalite can be considered as technological markers associated to the Joques production and then be used to identify imitations of this workshop. Braunite and kentrolite were identified in the brown decoration of the Catalan tablewares. The manganese pigment was probably mixed with a lead oxide compound and applied directly over the raw glaze. The presence of braunite and kentrolite indicates a firing temperature of about 950 °C. Thin-section petrography reveals that the crystallite growth has taken place under two different conditions. Euhedral braunite crystallites were produced during the heating. A drop in temperature during the firing process gave rise to the crystallization of dendritic braunite and kentrolite., Peer Reviewed, Postprint (author's final draft)

Hexagonal neo-formed crystallites have been observed in thin section of different medieval and post-medieval lead-glazed ceramics. Although they are clearly visible in thin section using plane polarized light, their plate shape makes them barely seen on the polished cross sections. Basal sections have never been found on the polished sections and only few transversal very thin sections could be seen. In this case, the morphology resembles acicular and it is not possible to analyze them properly by SEM–EDX because the crystals are very thin and the glaze surrounding is analyzed as well. Micro-Raman microscopy was carried out directly on the polished thin sections. This technique allows specific areas as small as 1 µm in diameter to be analyzed and it is able to characterize inclusions that are not found on the glaze surface. However, the wavenumber features observed cannot be assigned to a specific compound. The thickness of the crystallites (a few hundred nanometers) seems to be responsible for the low sensitivity of the Raman instrumentation. 15¿×¿15 µm2 micro-X-ray diffraction patterns using synchrotron radiation (SR-µXRD) in transmission geometry were obtained from the crystals using the same thin section preparation. SR-µXRD was able to localize the crystallites and avoid the overlapping signals corresponding to other mineral phases. In this way, the hexagonal crystallites present in the glaze have been unambiguously identified as hematite crystallites. Finally, some replications were made under laboratory-controlled conditions to determine the firing conditions in the formation of those crystallites. The presence of hematite coexisting with melanotekite indicates a firing temperature <925°C, while the presence of only hematite suggests a firing temperature >925°C, Postprint (published version)

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.

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.

[EN] In this paper we report the spectral properties of the stable radical adducts 1•–3•, which are formed by an electron donor moiety, the carbazole ring, and an electron acceptor moiety, the polychlorotriphenylmethyl radical. The molecular structure of radical adduct 1• in the crystalline state shows a torsion angle of approximately 90° between the phenyl and the carbazole rings due to steric interactions. They exhibit a charge transfer band in the visible range of the electronic spectrum. All of them are chemically oxidized with copper(II) perchlorate to the respective cation species, which show a strong charge transfer band into the near-infrared region of the spectrum. Radical adducts 1•–3• and the corresponding stable oxidized species 1+–3+ are real organic mixed-valence compounds due to the open-shell nature of their electronic structure. Charge transfer bands of the cation species are stronger and are bathochromically shifted with respect to those of the neutral species due to the greater acceptor ability of the positively charged central carbon atom of the triphenylmethyl moiety. The cationic species 1+–3+ are diamagnetic, as shown by the absence of a signal in the EPR spectrum in acetonitrile solution at room temperature, but they show an intense and unique band in frozen solutions

[EN] In this paper we report the spectral properties of the stable radical adducts 1•–3•, which are formed by an electron donor moiety, the carbazole ring, and an electron acceptor moiety, the polychlorotriphenylmethyl radical. The molecular structure of radical adduct 1• in the crystalline state shows a torsion angle of approximately 90° between the phenyl and the carbazole rings due to steric interactions. They exhibit a charge transfer band in the visible range of the electronic spectrum. All of them are chemically oxidized with copper(II) perchlorate to the respective cation species, which show a strong charge transfer band into the near-infrared region of the spectrum. Radical adducts 1•–3• and the corresponding stable oxidized species 1+–3+ are real organic mixed-valence compounds due to the open-shell nature of their electronic structure. Charge transfer bands of the cation species are stronger and are bathochromically shifted with respect to those of the neutral species due to the greater acceptor ability of the positively charged central carbon atom of the triphenylmethyl moiety. The cationic species 1+–3+ are diamagnetic, as shown by the absence of a signal in the EPR spectrum in acetonitrile solution at room temperature, but they show an intense and unique band in frozen solutions

La difracció de pols és una eina molt potent per a la determinació d’estructures cristal·lines de compostos tant iònicscom 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.Paraules clau: Difracció de pols, difracció de raigs X, radiació sincrotrònica, determinació estructural, estructura cristal·lina, compostos moleculars, fàrmacs., 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.Keywords: Powder diffraction, X-ray diffraction, synchrotron radiation, structure determination, crystal structure, molecularcompounds, pharmaceuticals.

La difracció de pols és una eina molt potent per a la determinació d’estructures cristal·lines de compostos tant iònicscom 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.Paraules clau: Difracció de pols, difracció de raigs X, radiació sincrotrònica, determinació estructural, estructura cristal·lina, compostos moleculars, fàrmacs., 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.Keywords: Powder diffraction, X-ray diffraction, synchrotron radiation, structure determination, crystal structure, molecularcompounds, pharmaceuticals.