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Eutectic mixtures are usually studied by differential scanning calorimetry (DSC), able to identify the transition temperatures, possible hysteresis, and investigate the energetic features of transformations. However, DSC is not able to give compositional, structural, or morphological information. A new approach is proposed exploiting powder X-ray diffraction (XRPD) and imaging to overcome the issues posed to diffraction by the presence of an amorphous liquid phase. Principal component analysis (PCA) is applied blindly to in situ XRPD data from both solid and liquid phases in an approach called differential scanning diffraction (DSD), with PCA scores being the reaction coordinate of melting or crystallization steps. PCA was used in a similar way to analyze the imaging data in what was named differential scanning imaging (DSI). Exploiting this approach, the structural and morphological changes during phase transitions can be characterized by XRPD and imaging respectively, complementarily to the energetic effects probed by DSC. Melting and crystallization points can be identified together with the hysteresis between downward and upward temperature ramps, by the structural and morphological viewpoints. A three-component mixture (NaBr, KCl, and water), with wide industrial applications, was studied to describe the behavior around the eutectic composition and examine how small mixture changes can affect the transition temperature and the freezing/melting behaviors. The phase composition at the solid state was elucidated and a new phase of NaBr was identified and its lattice parameters were obtained by XRPD. DSD and DSI resulted complementary to traditional DSC data with many potential applications in solid state chemistry and materials science.

The durability of food items, i.e. their shelf life, plays a crucial role in optimizing their quality and exploitation with the aim of limiting food and beverage waste. The primary factor contributing to prolonged deterioration is the oxidation of food products, leading to the generation of by-products that compromise their sensory qualities, such as off-flavors and organoleptic features in general. Concerning beverages, and wine in particular, polyphenols from wood and grapes extracts have gained significant popularity as natural agents able to preserve the quality and desired features due to their recognized antioxidant and anti-radical properties. Although the ability of oak to release polyphenols able to enhance the long-term stability of wines is widely acknowledged, effective methods for monitoring both their kinetics of oxidation and browning are still lacking. A spectrophotometric approach was exploited to develop a novel method for monitoring wine oxidation in the attempt of filling the gap. Such approach was successfully applied to track qualitatively the aging kinetics in oxidative conditions using a wine simulant with the addition of 16 natural extracts. Chestnut and oak extracts resulted the most performing in both hue conservation and oxidized species limitation. Principal component analysis demonstrated that polyphenol of different class can be recognized even after 30 days of oxidation, thus suggesting potential applications of the method in quality and conformity control of polyphenol extracts. The results allow a rational choice of the best polyphenol extract for each specific application in wines, with potential application to other beverages and foods.

A new soft and fast solid state reaction is exploited for the preparation of exchanged layered double hydroxide materials and, in particular, for intercalating bioactive molecules. The characterization of the nanocomposite, carried out by crystallographic and thermogravimetric techniques, revealed that this synthesis yield is comparable to that of standard methods but with time, solvent, and energy saving advantages. Moreover, the in situdiffraction experiments also allowed us to shed some light on the kinetics of the intercalation process.

This work reports on the positive impact of (i) attaching methoxy groups at the ortho position of the bipyridine ligand (6,6′-dimethoxy-2,2′-bipyridine) in heteroleptic copper(I) complexes belonging to the [Cu(bpy)(POP)]+family, and (ii) a new device design comprising a multilayered architecture to decouple hole/electron injection and transport processes on the performance of light-emitting electrochemical cells (LECs). In short, the substituted complex showed enhanced thermal- and photostability, photoluminescence, and ionic conductivity features in thin films compared to those of the archetypal complex without substitution. These beneficial features led to LECs outperforming reference devices in terms of luminance, stability, and efficacy. Furthermore, a new device design resulted in a 10-fold enhancement of the stability without negatively affecting the other figures of merit. Here, hole/electron injection and transport processes are performed at two different layers, while electron injection and electron–hole recombination occur at the copper(I) complex layer. As such, this work provides further insights into a smart design of N^N ligands for copper(I) complexes, opening the path to a simple device architecture toward an enhanced electroluminescence response.

The crystal structure of sodium naphthalene 2-sulfonate (Na2-NS) is reported. This compound raised the attention as a pollutant, being widely used in industry, and its intercalation in inorganic matrices, such as layered double hydroxides (LDH), could be a suitable removal strategy. The crystal structure of the title compound, despite its simplicity, is not known in the literature, so we looked for a strategy to grow crystals suitable for a single crystal study. Although many attempts were made to recrystallize it, Na2-NS grows in bunches of very thin laminae, with a high degree of mosaicity and intergrowth, explaining the absence of a reported crystal structure. The crystal structure shows layers of Na+cations with the organic part arranged in between. The crystals grow easily in the layer plane, whilst the growth perpendicular to the layers is driven by weak non-bonding interaction and thus unfavored. The crystal packing features were related to the density of charges in the cationic layer with respect to the size of the anion. By comparing the crystal structures of 2-NS salts with different cations, and with or without an amino substituent in different positions, it was possible to find the relationship between the density of the positive charges and the deepness of interdigitation of the 2-NS moieties. We exploited this information to shed light on the structural features of 2-NS and related compounds intercalated into LDH. The X-ray powder diffraction pattern of 2-NS intercalated LDH (V. Toson, E. Conterosito, L. Palin, et al. Facile intercalation of organic molecules into hydrotalcites by liquid-assisted grinding: yield optimization by a chemometric approach. Cryst. Growth Des.2015, 15, 5368) resulted consistent with a crystal packing characterized by the partial interdigitation of the 2-NS anions.

Abstract: Structured overlay networks are highly susceptible to attacks aimed at subverting their structure or functionalities. Although many secure architectural design proposals have been presented in the past, a widely accepted and comprehensive solution is lacking. Likir (Layered Identity-based Kademlia-like Infrastructure) is our solution for implementing a secure Peer-to-Peer network based on a Distributed Hash Table. Our purpose is to focus on three main goals: (1) providing security services and a secure overlay infrastructure against the vast majority of security threats on P2P systems, (2) dynamically creating a bridge between randomly generated peer identifiers and user identities, and (3) supplying the developer with a middleware API that can easily deal with peers’ identities. Placing the emphasis on user identity results in a highly secure distributed framework which is very fitting for privacy-aware and efficient implementation of identity-based applications like social networking applications. Detailed security analysis and performance evaluation are provided. Moreover, an implementation of Likir is introduced and a case study is presented in order to show its practical use in a real-life example.

The structure of [Fe(Htrz)2(trz)]BF4(1, Htrz =1,2,4-4-H-triazole, trz = 1,2,4-triazolate) at the low-spin (LS) and high-spin (HS) states and structural transitions between the two states were investigated by in situ high-resolution synchrotron X-ray powder diffraction (XRPD) combined with Raman spectroscopy using a modulation-enhanced technique. The crystal structures of the LS and HS states were determined. A 1D chain structure of 1at both LS and HS states was proven, and the lattice expansion upon LS−HS transition was mainly caused by the elongation of the chain. The differences in the behavior of the spin transition observed by XRPD and Raman spectroscopy were explained by the local sensitivity of the two different techniques and also by the spatial propagation of spin crossover phase transition within the crystallite and the body of the grain. Moreover, we demonstrated that the two-dimensional correlation analyses facilitate (i) understanding the data obtained by combined techniques, (ii) clarifying correlation between the signals gained by the different probes, and (iii) extracting information on temporal evolution of transformation processes.

The possible interactions between luminescent moieties with hydrotalcite HTLC host have been investigated. We present the work done in synthesizing luminescent materials containing coumarin3carboxylic acid 3CCA. A hydrothermal synthesis is carried out to intercalate the 3CCA into the HTLC with empirical formula: MII0.65MIII0.35OH2X0.35 · nH20, where MII  Zn2, MIII  Al3, X  3CCA−or NO3−. The ZnAl HTLC materials with MIIMIII  2.0 thus synthesized were characterized by XRPDFTIRICPMSTGASEM techniques and solidstate luminescent measurements. The thermal stability and the luminescent properties of obtained hybrid materials are promising because of the observed photoluminescence in the visible region and their hightemperature resistance indicated by the in situXRPD measurements and TGADTG analysis.

Siliceous or carbonate spicules provide support and defense to marine sponges. The inorganic envelope usually embodies a protein core. Our SAXS study of the siliceous spicules from the demosponge Thetya aurantium proves the very ordered structure assumed by the protein core inside the spicules. Indeed, not only the very sharp diffraction spots already found in previous studies on spicules from different sponges are confirmed, but also the 11 sharp spots in the diffraction pattern recorded after thermal treatment at 250°C can only be interpreted in terms of a natural nanocomposite mesostructure with an hexagonal lattice formed by a three-dimensional periodic arrangement of silica cages in which the protein units act as structure directing agent.

The ligand N-(2-pyridylmethyl)anthracene-9-carboxaldimine (1) has been synthesized and characterized by NMR spectroscopic techniques. The experimental procedure leads selectively to the E isomer, which has been studied by a combined theoretical (Density Functional Theory) and 2D NOESY NMR spectroscopic approach. The trifluoroacetic acid promotes the E to Z isomerization of 1. The process has been investigated by NMR spectroscopy and computationally for the neutral ligand 1. DFT methods calculate that the E isomer is 2.2 kcal/mol more stable than the Z isomer, whereas the reverse situation is observed for the protonated species, where the Z isomer is 4.5 kcal/mol more stable than the E isomer. Transition state calculations for the interconversion of the neutral and protonated E species into their corresponding Z isomers show that the energy barriers are 27.6 and 20.3 kcal/mol for the neutral and protonated species, respectively. The reaction with pentacarbonylchlororhenium leads, in the absence and in the presence of trifluoroacetic acid, to the synthesis of the corresponding tricarbonylchlororhenium isomer complexes Re-E-1 and Re-Z-1, respectively. Compounds Re-E-1 and Re-Z-1 were characterized by 1D and 2D NMR spectroscopy in solution, and their crystal structures were determined. Their photophysical and electrochemical properties are also reported. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

A series of photoactive complexes of [RuIIbis(bipyridyl){2-(4-methylpyridin-2-yl)benzo[d]-X-azole}](PF6)2 (X = N–CH3, 1; S, 2; or O, 3) have been synthesized and fully characterized by proton and 13C NMR spectroscopy and UV/Vis spectroscopy. The X-ray structure of 1 is also reported. The electrochemical behavior and the photophysical properties of 1–3 have been investigated. Cyclic voltammetry (CV) reveals the presence of three consecutive one-electron reduction processes and a single one-electron oxidation process that are chemically and electrochemically reversible. In all cases, electrogenerated chemiluminescence (ECL) has been observed in the presence of the co-reactant tri-n-propylamine (TPA). An analogue of 1 has been synthesized, [RuIIbis(bipyridyl){2-(4-methylpyridin-2-yl)benzo[d]-X-azole}](PF6)2 [X = N(CH2)5CO2H, 4], it has been coupled with bovine serum albumin (BSA), and its photophysical properties investigated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Treatment of the germacrane ketone 8-dehydro-12-O-methyl-deacylhallerin (2) with bases under conditions of thermodynamic enolization resulted in complete epimerization at the adjacent carbon atom C-7, with formation of 3. The conformational features of the epimeric ketones 2 and 3 were investigated by X-ray crystal structure analysis, NMR spectroscopy, molecular mechanics and dynamics simulations and ab initio calculations. While 2 showed temperature-insensitive sharp 1H NMR signals, its epimer 3 showed only broad lines. These spectral features suggest that 2 is monorotameric, while 3 is a mixture of different conformers, as was verified by molecular mechanics and dynamics calculations. Upon UV irradiation, 2 underwent isomerization at the C1–C10 double bond, while 3 was unreactive. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

The new H-bonded complex [Os(bpy)2(CO)(EtO···H-DMAP)][PF6]2, where DMAP = 4-(dimethylamino)pyridine and bpy = 2,2′-bipyridine, has been synthesized and characterized by X-ray diffraction, IR, solution and solid-state NMR spectroscopy. The complex shows a strong hydrogen bond between the protonated DMAP moiety and the deprotonated ethanolic group directly bonded to the Os atom. High-speed (28 KHz) solid-state 1H MAS NMR spectroscopy and quantum-mechanical calculations were used to assess the location of the hydrogen atom involved in the H-bond. Both confirmed a proton characteristic of an N−H···O−Y hydrogen bond. A molecular orbital analysis was performed to elucidate the IR CO stretching frequency red shift of the H-bonded complex with respect to [Os(bpy)2(CO)O(H)Et][OTf]2. Absorption spectra indicate that the H-bond is present both in water and dichloromethane solutions. However, no direct evidence of the H-bond interaction in solution is observed from the 1H NMR spectrum (CD2Cl2) between 298 and 193 K. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Siliceous sponges, one of the few animal groups involved in a biosilicification process, deposit hydrated silica in discrete skeletal elements called spicules. A multidisciplinary analysis of the structural features of the protein axial filaments inside the spicules of a number of marine sponges, belonging to two different classes (Demospongiae and Hexactinellida), is presented, together with a preliminary analysis of the biosilicification process. The study was carried out by a unique combination of techniques: fiber diffraction using synchrotron radiation, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetric (DSC), Fourier transform infrared spectroscopy (FTIR), and molecular modeling. From a phylogenetic point of view, the main result is the structural difference between the dimension and packing of the protein units in the spicule filaments of the Demospongiae and the Hexactinellida species. Models of the protein organization in the spicule axial filaments, consistent with the various experimental evidences, are given. The three different species of demosponges analyzed have similar general structural features, but they differ in the degree of order. The structural information on the spicule axial filaments can help shed some light on the still unknown molecular mechanisms controlling biosilicification.

Co-deposition from concentrated solutions of C60 and Fe[C5(CH3)5]2 affords two solid products in different yields. The major product 1, in the form of regular shaped crystals, has been investigated by X-ray diffraction, ¹³C CPMAS NMR and vibrational spectroscopy, which showed it to be a co-crystalline adduct of C60 and Fe[C5(CH3)5]2 with no significant electron charge transfer between the two building blocks. The minor product 2, in the form of an amorphous powder, has been investigated by vibrational techniques. Both IR and Raman spectra are consistent with a solid structure in which electron transfer between the two units appears to be possible. ((© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

The intramolecular cycloaddition of 14, with dimethylaluminium chloride as a catalyst and under kinetic control, yielded the exo adduct 19a. Opening of the oxygen bridge in the reduced adduct 20 gave intermediate 21. Oxidation of the latter made it possible to introduce the methyl group at C-10, which exclusively afforded 23, with the unnatural configuration. Further conversion resulted in the formation of D-homo-10-epi-adrenosterone (25). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

The intramolecular cycloaddition of 5 yields the unsaturated lactones 17a, 17b, and 17c as three major isomeric adducts. These were further reduced to the corresponding derivatives 21a, 21b, and 21c, which are intermediates for the synthesis of (+)-himbacine and stereoisomers thereof. Precursor 5 was obtained in a short convergent way using Sonogashira and Stille coupling reactions as the main C−C bond construction reactions.

No Abstract Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2001/2000/z14677_s.pdf or from the author.

No Abstract Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2000/z14677_s.pdf or from the author.

The title compound, 1‐(2′,3′‐di­deoxy‐β‐d‐glycero‐pent‐2‐eno­furan­osyl)­thymine 1‐methyl‐2‐pyrrolidone solvate, C10H12N2O4·­C5H9NO, is an NMPO solvate of the anti‐AIDS agent D4T. In its crystal structure, both the pyrimidine and the furan­ose rings are planar and approximately perpendicular [82.1 (4)°]. The value of the torsion angle defining the orientation of the thymine with respect to the joined furane, χ = −100.8 (4)°, and that of the torsion angle giving the orientation of the hydroxyl group linked to the furane ring, γ = 52.9 (5)°, show that the gly­cosyl­ic link adopts the so‐called high‐anticonformation and the 5′‐hydroxyl group is in the +scposition. The NMPO solvate is linked to the nucleoside through a fairly strong hydrogen bond.

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