Diaryldichalcogenide radical cations

One-electron oxidation of two series of diaryldichalcogenides (C₆F₅E)₂ (13a–c) and (2,6-Mes₂C₆H₃E)₂ (16a–c) was studied (E = S, Se, Te). The reaction of 13a and 13b with AsF₅ and SbF₅ gave rise to the formation of thermally unstable radical cations [(C₆F₅S)₂]˙⁺ (14a) and [(C₆F₅Se)₂]˙⁺ (14b) that were isolated as [Sb₂F₁₁]^– and [As₂F₁₁]^– salts, respectively. The reaction of 13c with AsF₅ afforded only the product of a Te–C bond cleavage, namely the previously known dication [Te₄]²⁺ that was isolated as [AsF₆]^– salt. The reaction of (2,6-Mes₂C₆H₃E)₂ (16a–c) with [NO][SbF₆] provided the corresponding radical cations [(2,6-Mes₂C₆H₃E)₂]˙⁺ (17a–c; E = S, Se, Te) in the form of thermally stable [SbF₆]^– salts in nearly quantitative yields. The electronic and structural properties of these radical cations were probed by X-ray diffraction analysis, EPR spectroscopy, and density functional theory calculations and other methods.     

Sugar Analogues with Basic Nitrogen in The Ring as Anti-Infectives

1. INTRODUCTION

Infectious diseases have remained a serious problem for society and concerned government organisations. Due to the dramatic increase of international transport of goods and passengers, dangerous microbial species and infectious diseases can be rapidly distributed over large distances. According to estimations by the World Health Organisation (WHO), nearly 50,000 people are killed by infectious diseases daily. After having been kept at bay for decades, tuberculosis has returned to claim over three million lives per year. In addition, approximately thirty new infectious diseases such as Legionnaire's disease, HIV, or borreliosis have emerged during the past two decades.¹ Furthermore, long-known species, for example mycobacteria, the causative agents of such diseases as tuberculosis and leprosy, have acquired a high level of resistance to most commonly employed anti-infective agents. Because of the abundance of pathogenic microorganisms, a tremendous fraction of the pharmaceutical market is devoted to anti-infective drugs. Of a $73 billion total global market of chiral drugs, antibiotics are the largest fraction ($20 billion) closely followed only by cardiovascular therapeutics ($17.5 billion).¹     

Effect of titanium ion substitution in the barium hexaferrite studied by M?ssbauer spectroscopy and X-ray diffraction

A series of M-type barium hexaferrite has been synthesized in a glass melt by partially substituting the Fe₂O₃ with TiO₂ for investigation of their structure. The glass melt has the basic composition (mol%): 40 BaO + 33 B₂O₃ + (27-x) Fe₂O₃ + x TiO₂ with x =?0, 3.6, 5.4 and 7.2 mol% TiO₂. The substituted ferrites were studied by means of X-ray diffraction, Mössbauer spectroscopy and vibration sample magnetometer. X-ray diffraction studies revealed that not all samples have a single ferritic phase, a small second phase corresponding to BaTi₆O₁₃ was also observed to form. The Mössbauer spectra changed from magnetically ordered (x =?0) to magnetically ordered with strong line broadening. Moreover, the broadening increases with TiO₂ content. The Mössbauer parameters suggested that Ti^4?+? occupies the 2a and 12k crystal sites, and the Ti^4?+? substitution on the 2b and 4f₂ site also occurs at high melt dopings. Therefore, coercivity and saturation magnetization decreased.     

Breath Analysis: Comparison among Methodological Approaches for Breath Sampling

Despite promising results obtained in the early diagnosis of several pathologies, breath analysis still remains an unused technique in clinical practice due to the lack of breath sampling standardized procedures able to guarantee a good repeatability and comparability of results. The most diffuse on an international scale breath sampling method uses polymeric bags, but, recently, devices named Mistral and ReCIVA, able to directly concentrate volatile organic compounds (VOCs) onto sorbent tubes, have been developed and launched on the market. In order to explore performances of these new automatic devices with respect to sampling in the polymeric bag and to study the differences in VOCs profile when whole or alveolar breath is collected and when pulmonary wash out with clean air is done, a tailored experimental design was developed. Three different breath sampling approaches were compared: (a) whole breath sampling by means of Tedlar bags, (b) the end-tidal breath collection using the Mistral sampler, and (c) the simultaneous collection of the whole and alveolar breath by using the ReCIVA. The obtained results showed that alveolar fraction of breath was relatively less affected by ambient air (AA) contaminants (p-values equal to 0.04 for Mistral and 0.002 for ReCIVA Low) with respect to whole breath (p-values equal to 0.97 for ReCIVA Whole). Compared to Tedlar bags, coherent results were obtained by using Mistral while lower VOCs levels were detected for samples (both breath and AA) collected by ReCIVA, likely due to uncorrected and fluctuating flow rates applied by this device. Finally, the analysis of all data also including data obtained by explorative analysis of the unique lung cancer (LC) breath sample showed that a clean air supply might determine a further confounding factor in breath analysis considering that lung wash-out is species-dependent.