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The Zaltoprofen/4,4'-Bipyridine system gives rise to two co-crystals of different compositions both endowed - in water and in buffer solution at pH 4.5 - with considerably higher solubility and dissolution rate than the pure drug. The qualitative and quantitative analysis of the DSC measurements, carried out on samples made up of mixtures prepared according to different methodologies, allows us to elaborate and propose an accurate thermodynamic model that fully takes into account the qualitative aspects of the complex experimental framework and which provides quantitative predictions (reaction enthalpies and compositions of the co-crystals) in excellent agreement with the experimental results. Co-crystal formation and cocrystal compositions were confirmed by X-ray diffraction measurements as well as by FT-IR and NMR spectroscopy measurements. The quantitative processing of DSC measurements rationalizes and deepens the scientific aspects underlying the so-called Tammann's triangle and constitutes a model of general validity. The work shows that DSC has enormous potential, which however can be fully exploited only by paying adequate attention to the experimental aspects and the quantitative processing of the measurements.

The present work aimed at decorating halloysite nanotubes (HNT) with magnetic Fe

Precipitation of mineral phosphates from wastewater treatment processes is an excellent method for phosphorus recovery, leading to the formation of compounds with high fertilizing value. Conventionally, P-precipitation processes are mostly applied to supernatant of anaerobic sludge digestates, due to their high P and N residual contents. This study concerns P-recovery in a pilot-scale side-stream reactor from aerobic (activated sludge) wastewater liquor. The effect of process retention time and pH was determined using sodium hydroxide and calcium hydroxide as alternative pH buffer reagents, in both synthetic and real wastewater. Equilibrium mass balance calculations were first applied to estimate the theoretical final composition of P-precipitates under different process conditions; then, actual precipitation experiments were carried out with synthetic wastewater to define optimal process operating parameters in controlled conditions. Results showed that phosphorus precipitation was affected mainly by solution pH and did not significantly depend on the reactor’s retention time. These findings were validated by operating the process with real wastewater: on average, 61.2% and 90.4% phosphorus precipitation (recovery) were achieved at pH = 8.5 and 9.0 under a controlled Mg:NH4:P molar ratio of 5:5:1, using sodium hydroxide as acidity buffer. The main fraction of final precipitates consisted of calcium phosphate compounds, while struvite, bobierrite and calcite showed up in smaller proportions. It was also shown that dosage of calcium hydroxide for pH adjustment, without any other chemicals for molar ratios adjustment of the solution, has great potential for P recovery in the form of a calcium phosphate-rich precipitate, usable for fertilizer, with 75.6% phosphorus removal in mineral form at pH = 8.5. The process is much less costly to operate than struvite precipitation, and more energetically sustainable. This scheme could be ideally suited for application in facilities operating under an enhanced phosphorus removal process scheme.

A simple not solvent and time consuming Fe3O4@MIL-100(Fe), synthesized in the presence of a small amount of magnetite (Fe3O4) nanoparticles (27.3 wt%), is here presented and discussed. Layer-by-layer alone (20 shell), and combined layer-by-layer (5 shell)/reflux or /hydrothermal synthetic procedures were compared. The last approach (Fe3O4@MIL-100_H sample) is suitable (i) to obtain rounded-shaped nanoparticles (200–400 nm diameter) of magnetite core and MIL-100(Fe) shell; (ii) to reduce the solvent and time consumption (the layer-by-layer procedure is applied only 5 times); (iii) to give the highest MIL-100(Fe) amount in the composite (72.7 vs. 18.5 wt% in the layer-by-layer alone); (iv) to obtain a high surface area of 3546 m2 g−1. The MIL-100(Fe) sample was also synthesized and both materials were tested for the absorption of Ofloxacin antibiotic (OFL). Langmuir model well describes OFL adsorption on Fe3O4@MIL-100_H, indicating an even higher adsorption capacity (218 ± 7 mg g−1) with respect to MIL-100 (123 ± 5 mg g−1). Chemisorption regulates the kinetic process on both the composite materials. Fe3O4@MIL-100_H performance was then verified for OFL removal at µg per liter in tap and river waters, and compared with MIL-100. Its relevant and higher adsorption efficiency and the magnetic behavior make it an excellent candidate for environmental depollution.

The eco-friendly method of kneading was here used to synthesize a cocrystal of probenecid, an uricosuric drug used in treating gout and hyperuricemia, with the aim to improve its pharmaceutical behavior. Benzamide was selected as a co-former showing functional groups favorable to the formation of supramolecular synthons with the active principle. The kneading product was characterized by a range of experimental techniques (microscopic, spectroscopic, thermal and diffractometric) all proving the formation of the new multicomponent crystal. In particular, the FT-IR and NMR techniques showed that an important change of hydrogen bonds network takes place in the kneading product and that the acid–acid interaction in the pristine drug is replaced with the related acid-amide one in the cocrystal. The cocrystal solubility and dissolution rate measured in several biorelevant fluids showed an actual improvement with respect to the pure drug.

The use of nanohybrids containing cationic or anionic inorganic compounds, seems particularly promising as efficient strategy for drug delivery. In fact, the inorganic counterions usually present in the host can be easily exchanged with drug molecules, from antitumor to anti-inflammatory, antibiotics and vitamins, giving rise to composites with improved solubility. An interesting inorganic host emerging for different applications, from catalysis to water purification up to pharmaceutics, is the layered double hydroxide (LDH) possessing a sheets structure and formula [$${\text{M}}_{{1 - {\text{x}}}}^{2 + }$$$${\text{M}}_{\text{x}}^{3 + }$$ (OH)2](An−)x/n yH2O (M2+ = Zn, Mg; M3+ = Al; An− = nitrates, carbonates, chlorides). In this paper, we synthesize by co-precipitation and reconstruction methods the hybrid compound Meloxicam-Zn3Al-LDH, particularly useful for a poorly soluble anti-inflammatory drug. The effective drug intercalation into LDH was verified through X-ray powder diffraction, thermal measurement and infrared spectroscopy. In addition, microscopy/microanalysis supported the formation of new entities. The dissolution tests clearly demonstrate an amazing improvement of the drug release rate with respect to marketed compounds when meloxicam is in the form of hybrid compound.

The present work is a concrete example of how physico-chemical studies, if performed in depth, are crucial to understand the behavior of pharmaceutical solids and constitute a solid basis for the control of the reproducibility of the industrial batches. In particular, a deep study of the thermal behavior of glipizide, a hypoglycemic drug, was carried out with the aim of clarifying whether the recognition of its polymorphic forms can really be done on the basis of the endothermic peak that the literature studies attribute to the melting of the compound. A number of analytical techniques were used: thermal techniques (DSC, TGA), X-ray powder diffraction (XRPD), FT-IR spectroscopy and scanning electron microscopy (SEM). Great attention was paid to the experimental design and to the interpretation of the combined results obtained by all these techniques. We proved that the attribution of the endothermic peak shown by glipizide to its melting was actually wrong. The DSC peak is no doubt triggered by a decomposition process that involves gas evolution (cyclohexanamine and carbon dioxide) and formation of 5-methyl-N-[2-(4-sulphamoylphenyl) ethyl] pyrazine-2-carboxamide, which remains as decomposition residue. Thermal treatments properly designed and the combined use of DSC with FT-IR and XRPD led to identifying a new polymorphic form of 5-methyl-N-[2-(4-sulphamoylphenyl) ethyl] pyrazine-2-carboxamide, which is obtained by crystallization from the melt. Hence, our results put into evidence that the check of the polymorphic form of glipizide cannot be based on the temperature values of the DSC peak, since such a peak is due to a decomposition process whose Tonset value is strongly affected by the particle size. Kinetic studies of the decomposition process show the high stability of solid glipizide at room temperature.

Two different zinc-based metal-organic frameworks (MOFs) were investigated to remove one of the most used fluoroquinolone antibiotic, Ofloxacin (OFL), from polluted water. The most common zeolitic imidazolate framework-8 (ZIF-8) and the green Zn(II) and benzene-1,3,5-tri-carboxylate (Zn3(BTC)2) were prepared through a facile synthetic route and characterized by means of Fourier-Transform Infrared (FT-IR) Spectroscopy, X-ray Powder Diffraction (XRPD), and Scanning Electron Microscopy (SEM) analyses. The two MOFs were compared in terms of both adsorption and kinetic aspects under real conditions (tap water, natural pH). Results showed that OFL was adsorbed in remarkable amounts, 95 ± 10 and 25.3 ± 0.8 mg g−1 on ZIF-8 and Zn3(BTC)2, respectively, following different mechanisms. Specifically, a Langmuir model well described the ZIF-8 profile, while for Zn3(BTC)2, cooperative adsorption occurred. Moreover the kinetic results were quite different, pseudo-second-order and sigmoidal, respectively. The suitability of ZIF-8 and Zn3(BTC)2 as adsorbent phases for water depollution was tested on tap water samples spiked with OFL 10 µg L−1. The obtained removal efficiencies, of 88% for ZIF-8 and 72% for Zn3(BTC)2, make these materials promising candidates for removing fluoroquinolone antibiotics (FQs) from polluted waters, notwithstanding their limited reusability in tap water, as demonstrated by in-depth characterization of the two MOFs after usage.

To improve the electrochemical performance of the LiNi 0.5 Mn 1.5 O 4 high voltage cathode for Lithium Ion Batteries, silicon-doped LiNi 0.5 Mn 1.5−x Si x O 4 samples (0.00 ≤ x ≤ 0.35) were prepared by different synthesis routes (solid-state reaction and ball milling) and characterized. The X-ray diffraction investigation and structural and profile Rietveld refinement put into evidence that effective spinel doping is obtained by the ball milling route: a solubility limit is achieved for x = 0.10 and silicon preferentially occupies the 8a tetrahedral site of the spinel structure, thus causing lithium to occupy both the tetrahedral and octahedral sites. In contrast, segregation of lithium silicates in the solid-state synthesis is observed. SEM images show that, independent on the synthesis method, silicon controls the particles morphology and grain size. The doped samples show improved electrochemical performances, which can be ascribed to the role of silicon in increasing cations disorder and controlling particles size.

Spinel ferrites are an amazing class of materials that can find application in different fields, from sensors and lithium-ion batteries to the intriguing biomedical field. For the use as anode in lithium-ion batteries, ZnFe2O4 is rather competitive due to low price, abundance, environmental benignity, working voltage of ~1.5 V, and, most importantly, a high theoretical specific capacity (~1072 mA h g−1). For its practical application, however, some issues must be overcome, in particular its fast capacity fading and poor rate capability resulting from an inherent low electronic conductivity. Possible strategies are represented by ferrite carbon coating/embedding, peculiar synthesis routes, and doping. In this frame, we synthesized Ca- and Al-doped ZnFe2O4 nanoparticles by using microwave-assisted combustion synthesis, followed by a classical carbon coating (determined as about 5 wt% by thermogravimetry). A good solubility of Ca and Al up to 25 atom% on both Zn and Fe sites was obtained. Cyclic voltammetries evidenced redox reactions involving Zn and Fe ions, but also the Al intervention could be supposed. Galvanostatic charge–discharge cycles proved that particularly Al ions were useful to improve the anode structural stability at high C rate (up to 3C), thanks to the stronger Al–O bonds with respect to Fe–O ones. A further improvement of capacities comes from the use of sodium alginate as binder to substitute polyvinylidene fluoride in the anode preparation.

ZnFe2O4 ferrite nanoparticles are arousing a great interest in the biomedical field, in particular for magnetic hyperthermia application, thanks to their superparamagnetic behaviour at room temperature. In order to better tuning the magnetic properties, different doping substitution and synthesis methods have been tried to reduce particle sizes and to vary the cation distribution on the spinel sites. In this paper, we focused on the microwave combustion synthesis method of Ca (on Zn site) and Gd (on Fe site) substituted ferrites. Undoped ZnFe2O4 and Sr and Al doped samples were also synthesized for comparison. The use of X-ray powder diffraction, microscopic and spectroscopic techniques allowed us to ensure the good quality of the spinel structure for all the investigated samples, to determine a homogeneous distribution of the dopants and an average particle size lower than 11 nm. In addition, we estimated the inversion degree of the spinels by using the Rietveld structural refinement and Raman spectroscopy. By means of SQUID magnetometry we found, for all the samples, a superparamagnetic behaviour with saturation magnetization between 6 and 10 emu/g at the maximum applied magnetic field of 3T, with a more effective role played by Ca ions with respect to Gd ions substitution.

FeNb11O29 is an intriguing and promising material that has been emerging in the last few years. It is isostructural with Nb12O29, one of the rare compounds in which Nb displays a local magnetic moment and shows both antiferromagnetic ordering and metallic conductivity at low temperatures. Both the two polymorphic monoclinic and orthorhombic forms have a mono-dimensional magnetic arrangement, but the different disposition of the structural building blocks leads to a strong frustration phenomenon of the magnetic order in the high-temperature orthorhombic form. Whereas Nb12O29 has been widely studied, barely few magnetic data can be found on its analogous FeNb11O29, for which a role of the Fe3+ localized d electrons in affecting the original magnetic behaviour can be foreseen. In this paper, we report how we synthesized undoped and, for the first time, Mn- and V-doped FeNb11O29. Both the monoclinic and orthorhombic polymorphs, stable in different temperature ranges, were then thoroughly structurally characterized. With the help of micro-Raman spectroscopy, we investigated the differences introduced into the vibrational levels by doping, while EPR data allowed us to obtain information on the transition metal ions and to point out the related peculiar structural features. Static magnetization measurements evidenced the paramagnetic character of the compounds and the high-spin configuration of Fe3+ ions.

The development of efficient strategies for drug delivery is considerably desired. Indeed, often several issues such as the drug solubility, the control of the drug release rate, the targeted delivery of drugs, the drug bioavailability, and the minimization of secondary effects still present great obstacles. Different methodologies have been proposed, but the use of nano-hybrids compounds that combine organic and inorganic substances seems particularly promising. An interesting inorganic host is the layered double hydroxide (LDH) with a sheets structure and formula [M 2+ 1−x M 3+ x (OH) 2 ](A n− ) x/n yH 2 O (M 2+ = Zn, Mg; M 3+ = Al; A n− = nitrates, carbonates, chlorides). The possibility to exchange these counterions with drug molecules makes these systems ideal candidates for the drug delivery. In this article, we synthesize by co-precipitation method the hybrid compound Carprofen-Zn 2 Al-LDH. Carprofen, a poorly soluble anti-inflammatory drug, could also benefit of the association with a natural antacid such as LDH, to reduce the gastric irritation after its administration. Through X-ray diffraction and Fourier-transformed infrared spectroscopy (FT-IR), we could verify the effective drug intercalation into LDH. The dissolution tests clearly demonstrate a significant improvement of the drug release rate when carprofen is in the form of hybrid compound.

The aim of this work was to search for new polymorphic forms of febantel, an anthelminthic drug of great present interest for the veterinary industry. Solvent-based recrystallization, thermal and mechanical treatments and spray drying were chosen to discover new solid forms. The solids obtained were physicochemically characterized by thermal techniques (DSC and TG), FTIR spectroscopy, laboratory and synchrotron X-ray powder diffraction and scanning electron microscopy. Our work leads to obtain a new solid form never described in the literature. In particular, the new polymorph was obtained by the anti-solvent method and the crystallization from isopropanol. The experimental conditions of crystallization favorable to the formation of the highest amount of the new solid phase were selected. The new phase shows a thermal, spectroscopic and diffractometric behavior unique. Furthermore, the preliminary structure investigation suggests two possible crystal systems: an orthorhombic or a monoclinic one, with really comparable lattice parameters and cell volume. Measurements put into evidence that the new phase is a metastable polymorph that is in monotropic relationship with the stable and known form.

Rechargeable all solid-state lithium batteries are a promising technology for the next generation of safer batteries. In this context, strict requirements are placed on the electrolytes, among which is emerging the Li7La3Zr2O12 garnet, chiefly for the relationships among synthesis conditions and phase stability. Here, the structural modifications of the low temperature (LT) Li7La3Zr2O12 cubic form were investigated by using in situ X-Rays diffraction analysis. In particular, we studied the role of both temperature and atmosphere (air or argon) on phase stabilization. In argon flow, the LT phase is stable under 750 °C, and it transforms into the tetragonal one at lower temperature. In air, it partially decomposes to La2Zr2O7 due to Li loss above 250 °C. ICP-OES analysis confirmed that garnet stoichiometry was maintained in argon, whereas in air lithium loss occurred. The structural transformations are driven by the CO2 absorbed in the LT structure that can form Li2CO3 and/or La2(CO3)3 so causing stoichiometry changes responsible of the structural evolution.

In this study, the maple wood surface was coated with nanostructured zinc oxide, grown on the surface by using a hydrothermal process, and furtherly treated with shellac varnish. Samples obtained both after ZnO treatment and after the final varnish application were characterized by different techniques, i.e., X-ray diffraction (XRD), scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDS), micro-FTIR with attenuated total reflectance (μ-ATR-FTIR), chromatic variation measurements, and contact angle determinations. Analytical results showed that the wood surface was covered by quite a homogeneous array of inorganic nanoparticles and that the natural resin forms a regular film over the ZnO nanostructures. An accelerated aging test was used to evaluate the protecting effectiveness of the treatments towards UV-induced decay of wood material. After the test, wood treated with ZnO and with the shellac/ZnO combination underwent a considerably lower chromatic change if compared to the untreated wood, suggesting an enhanced resistance of the treated maple to the decay due to light exposition. The presence of nanostructured ZnO protects from decay not only the wood substrate but also the shellac film. A microbiology test showed that growth of fungal species, e.g., common mold, is prevented on the wood surface treated with ZnO or with shellac/ZnO, indicating that the nanostructured zinc oxide also provides an effective protection from biodeterioration. The coating obtained by consecutive application of nanosized ZnO particles and shellac varnish combines the excellent aesthetical features and water repellence of the traditional finish with the protecting effectiveness of the nanostructured inorganic component.

Two different zinc-based metal-organic frameworks (MOFs) were investigated to remove one of the most used fluoroquinolone antibiotic, Ofloxacin (OFL), from polluted water. The most common zeolitic imidazolate framework-8 (ZIF-8) and the green Zn(II) and benzene-1,3,5-tri-carboxylate (Zn3(BTC)2) were prepared through a facile synthetic route and characterized by means of Fourier-Transform Infrared (FT-IR) Spectroscopy, X-Ray Powder Diffraction (XRPD), and Scanning Electron Microscopy (SEM) analyses. The two MOFs were compared in terms of both adsorption and kinetic aspects under real conditions (tap water, natural pH). Results showed that OFL was adsorbed in remarkable amounts, 95 ± 10 and 25.3 ± 0.8 mg g−1 on ZIF-8 and Zn3(BTC)2, respectively, following different mechanisms. Specifically, a Langmuir model well described the ZIF-8 profile, while for Zn3(BTC)2, cooperative adsorption occurred. Moreover the kinetic results were quite different, pseudo-second-order and sigmoidal, respectively. The suitability of ZIF-8 and Zn3(BTC)2 as adsorbent phases for water depollution was tested on tap water samples spiked with OFL 10 µg L−1. The obtained removal efficiencies, of 88% for ZIF-8 and 72% for Zn3(BTC)2, make these materials promising candidates for removing fluoroquinolone antibiotics (FQs) from polluted waters, notwithstanding their limited reusability in tap water, as demonstrated by in-depth characterization of the two MOFs after usage.

FeNb11O29 is an intriguing and promising material that has been emerging in the last few years. It is isostructural with Nb12O29, one of the rare compounds in which Nb displays a local magnetic moment and shows both antiferromagnetic ordering and metallic conductivity at low temperatures. Both the two polymorphic monoclinic and orthorhombic forms have a mono-dimensional magnetic arrangement, but the different disposition of the structural building blocks leads to a strong frustration phenomenon of the magnetic order in the high-temperature orthorhombic form. Whereas Nb12O29 has been widely studied, barely few magnetic data can be found on its analogous FeNb11O29, for which a role of the Fe3+ localized d electrons in affecting the original magnetic behaviour can be foreseen. In this paper, we report how we synthesized undoped and, for the first time, Mn- and V-doped FeNb11O29. Both the monoclinic and orthorhombic polymorphs, stable in different temperature ranges, were then thoroughly structurally characterized. With the help of micro-Raman spectroscopy, we investigated the differences introduced into the vibrational levels by doping, while EPR data allowed us to obtain information on the transition metal ions and to point out the related peculiar structural features. Static magnetization measurements evidenced the paramagnetic character of the compounds and the high-spin configuration of Fe3+ ions.

A detailed characterization of the polymorphs constituting cathode materials, both before and after cell cycling, is mandatory to develop more stable and powerful lithium batteries. In many cases, e.g., for transition metal lithium silicates, standard diffraction techniques cannot give a clear-cut response. Here we show that broadband adiabatic fast MAS NMR can give unique information in the case of model Li2(Mn,Fe)SiO4 high-capacity cathode materials. By coupling 7Li and 29Si 1D and 2D spectra, we are able to address polymorphs speciation also in the mixed Mn/Fe compositions, which is a nearly impossible task for X-rays and neutrons diffraction. We finally discuss the conditions under which this approach is useful when applied to rare nuclei such as 29Si.

The development of efficient strategies for drug delivery is considerably desired. Indeed, often several issues such as the drug solubility, the control of the drug release rate, the targeted delivery of drugs, the drug bioavailability, and the minimization of secondary effects still present great obstacles. Different methodologies have been proposed, but the use of nano-hybrids compounds that combine organic and inorganic substances seems particularly promising. An interesting inorganic host is the layered double hydroxide (LDH) with a sheets structure and formula [M

Lithium metal orthosilicates are attracting a lot of attention owing to their promising prospects as potential high capacity cathode materials for Li-ion batteries. Currently, great efforts are being made in order to achieve the full theoretical specific capacity of 330 mA h g(-1), but many issues remain unsolved (e.g., poor structural and cycling stability), which limit their practical application. The present perspective highlights the importance of assessing the electrochemical behaviour of Li2(Fe,Mn)SiO4 by combining an arsenal of characterization techniques both spectroscopic and structural, in and ex situ. Here, we review the most recent achievements in the investigation of the electrochemical performance of lithium metal orthosilicate cathodes and, through some of our recent results, we attempt to clarify the relationship between the structure and electrochemistry of these compounds.

This paper describes the structure and properties of the drug domperidone and a novel 1:1 domperidone succinate salt. The new salt is characterized by means of thermal, spectroscopic, microscopic and powder diffraction measurements. The crystal structures of the salt and, for the first time, of pure domperidone have been determined by means of single-crystal X-ray diffraction. In both structures, the piperidine ring of domperidone adopts the expected chair conformation, and supramolecular centrosymmetric R2(2)(8) motifs are formed by N-H...O hydrogen bonds between chlorine-substituted oxobenzimidazolyl groups. Further N-H...O hydrogen bonds occur between non-substituted oxobenzimidazolyl groups and the resulting C(4) motifs originates hydrogen-bonded chains, extending along the crystallographic b axis. In the salt, a single N-H...O hydrogen bond forms between the protonated nitrogen of the piperidine ring and the carboxylic O atom of the succinate ion. Two alternative and mutually exclusive positions for the nonsubstituted oxobenzimidazolyl group have also been observed; this disorder makes the hydrogen-bonded chains originating from the bicyclic group polar. The dissolution behaviour of the salt in dosage form is compared with two reference commercial products. The salt shows an increased solubility, a characteristic that could be of great advantage from a pharmaceutical view point.

Wood is a natural material that finds numerous and widespread applications, but is subject to different decay processes. Surface coating is the most common method used to protect wood against deterioration and to improve and stabilize its distinctive appearance. Shellac is a natural resin that has been widely used as a protective material for wooden artefacts (e.g. furniture, musical instruments), due to its excellent properties. Nevertheless, diffusion of shellac-based varnishes has significantly declined during the last decades, because of some limitations such as the softness of the coating, photo-degradation, and sensitivity to alcoholic solvents and to pH variations. In the present study, different inorganic nanoparticles were dispersed into dewaxed natural shellac and the resulting materials were investigated even after application on wood specimens in order to assess variations of the coating properties. Analyses performed by a variety of experimental techniques have shown that dispersed nanoparticles do not significantly affect some distinctive and desirable features of the shellac varnish such as chromatic aspect, film-forming ability, water repellence, and adhesion. On the other hand, the obtained results suggested that some weak points of the coating, such as low hardness and poor resistance to UV-induced ageing, can be improved by adding ZrO2 and ZnO nanoparticles, respectively.

Magnetite nanoparticles coated with silica, obtained by a sol-gel process in the reverse micelle microemulsion, were characterized and homogeneously suspended in water in order to assay their biocompatibility toward blood cells, in view of a potential medical use of this material. Their hemolytic, pro-thrombotic and pro-inflammatory properties were observed.

Improving cathode materials is mandatory for next-generation Li-ion batteries. Exploring polyanion compounds with high theoretical capacity such as the lithium metal orthosilicates, Li2MSiO4 is of great importance. In particular, mixed silicates represent an advancement with practical applications. Here we present results on a rapid solid state synthesis of mixed Li2(FeMnCo)SiO4 samples in a wide compositional range. The solid solution in the P21/n space group was found to be stable for high iron concentration or for a cobalt content up to about 0.3 atom per formula unit. Other compositions led to a mixture of polymorphs, namely Pmn21 and Pbn21. All the samples contained a variable amount of Fe3+ ions that was quantified by Mössbauer spectroscopy and confirmed by the TN values of the paramagnetic to antiferromagnetic transition. Preliminary characterization by cyclic voltammetry revealed the effect of Fe3+ on the electrochemical response. Further work is required to determine the impact of these electrode materials on lithium batteries.

Organosulfonic modified SBA-15 silicas are promising catalysts for a wide spectrum of organic reactions. In particular, their catalytic activity seems to be effective only when large amounts of functional groups are anchored to the silica skeleton. However, there is evidence that the ordered mesostructure is retained only for contents of sulfonic units not exceeding 20 mol%. In this paper, for the first time to our knowledge, we fully address the gradual structural disordering mechanisms of the SBA-15 silica functionalised with increasing amounts of propylsulfonic groups in the compositional range 0-70 mol%. This investigation was carried out by means of a multi-technique wide approach including thermal analysis, TEM, XRD, N2 adsorption, FTIR/Raman and solid-state multinuclear NMR. We obtained detailed information on the structural modifications of these hybrid systems as a consequence of the sulfonation process. In particular, we showed that high functionalization degrees lead to inhomogeneous materials made of inorganic or low-functionalized clusters where the SBA-15 structure is likely retained, and hybrid clusters where the hexagonal mesoporous structure is destroyed. Moreover, full conversion of -SH into -SO3H groups is efficient until 20 mol% functionalization. In fact for higher sulfonation degrees, the formation of S-S bridges becomes a competitive mechanism, which is predominant in the sample SO3H70%, where only about 20% of the introduced organic moieties are actually oxidized. Therefore, to push sulfonic functionalization above 20 mol% is not necessarily useful, at least for applications where ordered mesoporous structure is mandatory, such as in catalysis or in membranes for polymer fuel cells.

The global energy demand calls for more efficient storage systems. In this review, the state of the art of Li/air and Li/O 2 batteries is discussed with particular attention on the more recent findings regarding all the battery compartments. Both aqueous and non-aqueous systems are considered, and the most critical issues for better battery design are addressed. Whereas the predicted charge/discharge values for these devices do justify the intense research efforts performed nowadays, great problems are still present which must be overcome in order to make Li/air and Li/O 2 a reality for future large-scale applications.

The application of single-walled carbon nanotubes (SWCNTs) as saturable absorbers (SA) in a Nd:glass femtosecond laser is verified as a promising alternative to traditional semiconductor saturable-absorber mirrors (SESAMs). The shortest laser pulses achieved with a SWCNT-SA fabricated by the slow-evaporation method are reported herein. Nearly Fourier-limited 288 fs pulses are obtained with negative-dispersion soliton mode-locking. The importance of the properties of the starting material, such as the degree of purity and the chirality, and the successive slow-evaporation deposition method is proven by using a multitechnique approach based on X-ray diffractometry, scanning electron microscopy, and μ-Raman spectroscopy. The high degree of nanotube alignment on the glass substrate and also the slight metallic character due to electron transfer between the glass matrix and the nanotubes themselves are identified as the main features responsible for the good laser response.

Olivine-type LiFePO4 is nowadays one of the most important cathode materials of choice for highenergy lithium ion batteries. Its intrinsic defectivity, and chiefly the so-called lithium iron anti-site, is one of the most critical issues when envisaging electrochemical applications. This paper reports a combined diffractometric (Synchrotron Radiation XRD with Rietveld and PDF analyses) and spectroscopic (Moessbauer) approach able to give a thorough characterization of the material defectivity. Such analytical procedure has been applied to a sample prepared following an innovative microwave-assisted hydrothermal synthesis route that, in a few minutes, allowed us to obtain a well crystallized material. PDF analysis, which is applied for the first time to this type of battery material, reveals the presence of disorder possibly due to Li/Fe exchange or to a local symmetry lowering. A 5% amount of iron on the lithium site has been detected both by PDF as well as by Moessbauer spectroscopy, which revealed a small percentage of Fe3+ on the regular sites.

Carprofen co-crystals with selected co-formers were prepared by solvent evaporation and wet/dry grinding methods. Their effective formation was investigated by thermal analysis, FT-IR, X-ray single crystal and powder diffraction and SEM-EDS. This last technique has been applied for the first time to co-crystals since it provides unambiguous confirmation of co-crystal formation. Among the investigated co-formers we studied, only 4,4′-dipyridyl yields co-crystals. Two different crystal structures are obtained when the molar ratio of carprofen : 4,4′-dipyridyl is 2 : 1 (triclinic cell) and 1 : 1.5 (monoclinic cell). The asymmetric triclinic cell (Z = 2) contains two carprofen and two half 4,4′-dipyridyl moieties while the monoclinic cell (Z = 4) contains a single carprofen, and one and a half 4,4′-dipyridyl moieties. Several hydrogen-bond supramolecular synthons can be identified in the solid state. For both the 2 : 1 and 1 : 1.5 co-crystals, the main hydrogen-bond interaction consists of an O–H⋯N heterosynthon involving, as a donor, the COOH group of carprofen and, as a H-acceptor, the nitrogen of a 4,4′-dipyridyl molecule. The two co-crystals have characteristic FT-IR spectra and slightly different melting temperatures. X-Ray powder diffraction patterns of the 1 : 1 and 1 : 2 compositions reveal a mixture of phases, whose amount is quantified with Rietveld analysis.

The role of lithium excess and Mn doping on lithium titanium phosphate properties is studied by structural (X-ray and neutron diffraction) and spectroscopic (electron paramagnetic resonance and impedance) techniques. The dopant cation is present with 2+, 3+, and 4+ oxidation states in both the lithium and titanium sublattices: Mn2+ is preferentially located on Li sites and Mn4+ on Ti ones, and Mn3+ can occupy both the sites. The refinement of neutron diffraction patterns allowed us to identify the 18e crystallographic site as the preferred location of the excess Li ions. Cationic distribution and valence state are mainly related to sol–gel or solid-state synthesis routes. Consequently, the complex behavior of the bulk conductivity can be explained by the presence of Mn on the Li site and the amount of Li excess, while the effect of the sintering degree is comparable in all the samples as revealed by scanning electron microscopy.

Nicergoline (NIC), a poorly water-soluble semisynthetic ergot derivative, was crystallized from several organic solvents, obtaining two different polymorphic forms, the triclinic form I and the orthorhombic form II. NIC samples were then characterized by several techniques such as 13 C cross-polarization magic angle spinning solid-state spectroscopy, room-temperature and high-temperature X-ray powder diffraction, differential scanning calorimetry, and by analysis of weight loss, solvent content, powder density, morphology, and particle size. Solubility and intrinsic dissolution rates determined for the two polymorphic forms in water and hydrochloride solutions (HCl 0.1 N) were always higher for form II than for form I, which is actually the form used for the industrial preparation of NIC medicinal products. Preformulation studies might encourage industry for the evaluation of polymorph II, as it is more suitable for pharmaceutical applications. Results in drug delivery, as well as those obtained by the above-mentioned techniques, and the application of Burger–Ramberger's rules make it possible to conclude that there is a thermodynamic relation of monotropy between the two polymorphs. This last assumption may help formulators in predicting the relative stability of the two forms.

The role played by the substitution of Mn on the electrochemical behaviour of Li3V2(PO4)3 has been investigated. Independently of the synthesis route, the Mn doping improves the electrochemical features with respect to the undoped samples. Different reasons can be taken into consideration to explain the electrochemical enhancement. In the sol–gel synthesis the capacity slightly enhances due to the Mn substitution on both the V sites, within the solubility limit x = 0.124 in Li3V2−xMnx(PO4)3. In the solid state synthesis the significant capacity enhancement is preferentially due to the microstructural features of the crystallites and to the LiMnPO4 phase formation.

Thermal stability and phase homogeneity of the triphylite LiFePO4 compound were investigated by means of Raman spectroscopy. A detailed check of phase homogeneity of undoped samples obtained from different preparation routes—hydrothermal, sol–gel, and solid state synthesis—and Mn-doped compounds from solid-state synthesis was performed by means of a mapping of the Raman spectra. The triphylite compositional and structural properties were carefully investigated also with the help of structural refinements and magnetic techniques, which also allowed us to reveal and identify the impurity phases formed together with the olivine LiFePO4. The effect of laser irradiation on the triphylite thermal stability was thoroughly investigated and related to the synthesis route, to the doping, and to the sample homogeneity. The thermal stability of iron oxides, present both as synthesis products and as consequence of the irradiation itself, was also analyzed following the magnetitemaghemitehematite phase transformation. All the experimental observations concur in indicating that the effectiveness of the laser heating on these compounds mainly depends on grain size and the degree of order of the olivine structure, the highest thermal stability being displayed in the case of the nonhomogenous undoped samples obtained from solid-state preparation, which show a highly ordered triphylite phase. Copyright © 2010 John Wiley & Sons, Ltd.

Mo{sub 1-x}W{sub x}O{sub 3} oxides with different cationic fraction (x=0.2, 0.5 and 0.8) and, for comparison purposes, pure MoO{sub 3} and WO{sub 3} were prepared. Along with textural and structural characterizations, absorbance FT-IR, diffuse reflectance UV-vis-NIR and EPR spectroscopies were employed to study the changes in the electronic properties of these materials passing from Mo{sub 1-x}W{sub x}O{sub 3} in oxidizing atmosphere to Mo{sub 1-x}W{sub x}O{sub 3-{delta}} in reducing conditions. XRD analysis showed that the Mo-W mixed oxides are constituted by two or three crystalline phases, whose abundance and composition are well characterized by structural refinement with the Rietveld method. Only the sample with the highest Mo content (x=0.2) shows a predominant mixed phase and also a superior ability to lose oxygen with respect to the other mixed oxides. The oxygen loss in the reduced oxides induces the formation of defects with electronic levels in the band gap of the material, in particular, electrons trapped in oxygen vacancies and/or at cationic sites (polarons). While the nature of defect sites induced in the mixed and in the pure oxides is similar, the photo-ionization energies, the ratio between surface and bulk defects and the stability of the defects in oxygen at increasing temperaturemore » are peculiar of each mixed oxide. - Graphical abstract: The combined use of different techniques provides new insight into structural, optical and electronic properties of semiconductor Mo{sub 1-x}W{sub x}O{sub 3-{delta}} mixed oxides.« less