IR spectroscopic features of gaseous C7H7O+ ions: benzylium versus tropylium ion structures

Gaseous [C7H7O]+ ions have been formed by protonation of benzaldehyde or tropone (2,4,6-cycloheptatrienone) in the cell of an FT-ICR mass spectrometer using C2H5(+) as a Br?nsted acid. The so-formed species have been assayed by infrared multiphoton dissociation (IRMPD) using the free electron laser (FEL) at the CLIO (Centre Laser Infrarouge Orsay) facility. The IRMPD features are quite distinct for ions from the two different precursors, pointing to two different isomers. A number of potential structures for [C7H7O]+ ions have been optimized at the B3LYP/6-31+G(d,p) level of theory, and their relative energies and IR spectra are reported. On this basis, the IRMPD spectra of [C7H7O]+ ions are found to display features characteristic of O-protonated species, with no evidence of any further skeletal rearrangements. The so-formed ions are thus hydroxy-substituted benzylium and tropylium ions, respectively, representative members of the benzylium/tropylium ion family. The IRMPD assay using the FEL laser light has allowed their unambiguous discrimination where other mass spectrometric techniques have yielded a less conclusive answer.     

The PANDA physics programme

The PANDA experiment at the future FAIR facility in Darmstadt, Germany, will use interactions of antiprotons with nucleons or nuclei to investigate fundamental questions of hadron and nuclear physics. Here, a brief overview of the physics programme is given, focusing on a few selected topics.     

Geometry of acetylene chemisorption on Ni(100) investigated by leed intensity analysis: The c(2 × 2) structure

Results from LEED dynamical calculations performed on the Ni(100) c(2 × 2)C₂H₂ structure, produced by adsorption of C₂H₂ at about 273 K and 1.5 L exposure, are reported. Among the several model geometries tried, the most favoured one appears to be a distorted acetylene molecule with the midpoint of the CC bond (1.20 Å long) placed above the fourfold hollow site at a vertical distance 2.02 Å from the topmost Ni layer and with the CC axis itself tilted by 50° with respect to the surface normal in the [011] direction. In this geometry the NiC distance is 2.2 Å.     

Protein expression patterns associated with advanced stage ovarian cancer

This is a comparative proteomic study on biopsies from patients with ovarian cancer to identify potential diagnostic/prognostic biomarkers in both healthy and tumor tissue, interstitial fluid (normal interstitial fluid and tumoral interstitial fluid and peritoneal effusion. Protein expression/identification was evaluated by 2-DE and MS analysis: six proteins showed differential expression in tumoral interstitial fluid and tumor tissue compared to normal interstitial fluid and healthy tissue: five were found to be downregulated and identified as galectin 3, glutathione S-transferase A-2, retinol binding protein 1, phosphatidylethanolamine-binding protein and annexin 5, while the calgranulin, was significantly upregulated in all pathological samples, including the ascitic fluid. Validation of S100A8 overexpression in carcinoma tissue was obtained by immunohistochemistry. To our knowledge, this is the first study to report an over-expression of calgranulin by 2-DE associated with MS/MS analysis on surgical biopsy. The reduced expression of galectin 3 and retinol binding protein 1 in cystic fluid and serum of patients with early stage disease is confirmed in this study. The results highlight alterations in proteins that control cell-cycle progression and apoptosis, as well as factors that modulate the activity of signal transduction pathways. Moreover, this study suggests that calgranulin expression may be used as a diagnostic and/or prognostic biomarker.     

Electrochemical Organic Synthesis of Electron-Rich Biaryl Scaffolds: An Update

Biaryl scaffolds are widely spread in biologically important natural products, in numerous therapeutic agents, but they are also considered a privileged class of ligands and (organo)catalysts; therefore, the development of efficient alternative methodologies to prepare such compounds is always attracting much attention. The present review discusses the organic electrosynthesis of biaryls starting from phenols, anilines, naphthols, and naphthylamines. The most significant examples of the works reported in the last decade are presented and classified according to the single class of molecules: after the introduction, the first three sections relate to the reactions of phenols, naphthols, and anilines, respectively; the other two sections refer to cross-coupling and miscellaneous reactions.     

Thermal Decomposition and Melting of A New Carboxyindole Derivative

GV150526A is a novel 2-carboxyindole derivative, recently synthesized by GlaxoWellcome, which is used in treatment or prevention of CNS disorders resulting from neurotoxic damage. It has been prepared in three forms, F1, F2 and F3, having significantly different hydration/dehydration behavior and/or diffraction patterns. Here, we extend the thermal analysis of these polymorphs above 200°C, where all forms are fully dehydrated and the main thermal phenomena are decomposition and melting. Simultaneous TG/DSC measurements have been repeated in wet and dry nitrogen atmospheres over a wide range of heating rates. Form F3 displays a qualitatively different behavior relative to F1 and F2. This fact is interpreted as an evidence of a mechanism of decomposition which sets F3 apart from F1 andF2. The thermal data are summarized by simple heuristic equations and few ‘apparent’enthalpies. This revised version was published online in August 2006 with corrections to the Cover Date.     

Photoinduced water oxidation by a tetraruthenium polyoxometalate catalyst: ion-pairing and primary processes with Ru(bpy)3(2+) photosensitizer

The tetraruthenium polyoxometalate [Ru(4)(μ-O)(4)(μ-OH)(2)(H(2)O)(4)(γ-SiW(10)O(36))(2)](10-) (1) behaves as a very efficient water oxidation catalyst in photocatalytic cycles using Ru(bpy)(3)(2+) as sensitizer and persulfate as sacrificial oxidant. Two interrelated issues relevant to this behavior have been examined in detail: (i) the effects of ion pairing between the polyanionic catalyst and the cationic Ru(bpy)(3)(2+) sensitizer, and (ii) the kinetics of hole transfer from the oxidized sensitizer to the catalyst. Complementary charge interactions in aqueous solution leads to an efficient static quenching of the Ru(bpy)(3)(2+) excited state. The quenching takes place in ion-paired species with an average 1:Ru(bpy)(3)(2+) stoichiometry of 1:4. It occurs by very fast (ca. 2 ps) electron transfer from the excited photosensitizer to the catalyst followed by fast (15-150 ps) charge recombination (reversible oxidative quenching mechanism). This process competes appreciably with the primary photoreaction of the excited sensitizer with the sacrificial oxidant, even in high ionic strength media. The Ru(bpy)(3)(3+) generated by photoreaction of the excited sensitizer with the sacrificial oxidant undergoes primary bimolecular hole scavenging by 1 at a remarkably high rate (3.6 ± 0.1 × 10(9) M(-1) s(-1)), emphasizing the kinetic advantages of this molecular species over, e.g., colloidal oxide particles as water oxidation catalysts. The kinetics of the subsequent steps and final oxygen evolution process involved in the full photocatalytic cycle are not known in detail. An indirect indication that all these processes are relatively fast, however, is provided by the flash photolysis experiments, where a single molecule of 1 is shown to undergo, in 40 ms, ca. 45 turnovers in Ru(bpy)(3)(3+) reduction. With the assumption that one molecule of oxygen released after four hole-scavenging events, this translates into a very high average turnover frequency (280 s(-1)) for oxygen production.     

Novel Foods and Sustainability as Means to Counteract Malnutrition in Madagascar

Although the trends of international reports show an increase in overweight and obesity, even in developing countries, there are still areas of the world, such as Sub-Saharan Africa, strongly affected by undernutrition. Specifically, in Madagascar, the percentage of stunted children under 5 is extremely high. Furthermore, the COVID-19 pandemic is expected to increase the risk of all forms of malnutrition, especially in low-income countries, including Madagascar, with serious intergenerational repercussions. This narrative review aims at investigating eating habits and cooking methods of the Malagasy population, addressing sustainable healthy diets through promotion of novel foods. While novel foods are a recent concept, there are data that describe how they may contribute to counteract food insecurity and malnutrition considering context and place. Efforts to promote native, traditional foods as Moringa oleifera, an indigenous plant in Asia and Africa including Madagascar, rich in protein and micronutrients, as well as edible insects, alternative sustainable source of protein, lipids, iron, and zinc, would provide not only nutritional but also cultural and economic benefits. The potential synergies between food traditions and agroecology have the potential to impact health addressing larger issues of sustainability and food security. Regional, national, and international policies are needed to develop and support one health approach actions.     

Ab initio valence bond calculations. VII. HF,HF+, and H2F+

Ab initio valence bond calculations for the ground and excited states of HF and HF⁺ are presented. Total energies, equilibrium geometries, dissociation energies, dipole moments, and spectroscopic constants for HF and HF⁺ have been calculated. The photoelectron spectrum of HF has been examined and interpreted by means of the valence bond formalism. The ground state of the protonated species H₂F⁺ has been investigated.