Structure elucidation of the dye Acid Red 131: complete 1H, 13C and 15N NMR data assignment

The chemistry of dyes and pigments is relevant to the textile industry, because of the importance to establish the best conditions for the finishing process and to understand the interactions among various compounds to yield the correct hue and nuances. For this reason, the molecular structure of a monoazo acid dye, C.I. Acid Red 131, was elucidated and characterized by homo‐ and hetero‐nuclear NMR, MS, IR and UV spectroscopy techniques. Copyright © 2011 John Wiley & Sons, Ltd.     

Weakness of multiple scattering effects in a slab of random medium

Summary Wave propagation in a stack of n slabs of equal thickness L/n, whose index of refraction is assumed to be random is considered. The behaviour of the wave function as n goes to infinity is studied.

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Sommario Si considera la propagazione ondosa in uno strato di materiale suddiviso in n parti di uguale spessore L/n, il cui indice di rifrazione è assunto aleatorio. Si studia il comportamento della funzione d'onda per n tendente a infinito.

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Presented at the VIII Congresso Nazionale dell'Associazione Italiana Di Meccanica Teorica ed Applicata (AIMETA), Torino, Ottobre 1986.     

Diels-Alder Reactions of. (+)-Apoverbenone

The thermal and catalyzed Diels-Alder reactions of (+)-apoverbenone (1) with isoprene, 2, 3-dimethyl-1,3-butadiene, (E)-piperylene, (E)-1-methoxy-1,3-butadiene and cyclopentadiene are described; structural analysis by ¹H and ¹³C-NMR spectroscopy is reported, and the syn-anti and endo-exo diastereoselectivity of the reactions is discussed.     

Determination of pharmaceutical compounds in sewage sludge using a standard addition method approach

An analytical method for the simultaneous determination of eight pharmaceutical compounds in biosolids from urban wastewater treatment plants (WWTPs) was developed and validated. The compounds evaluated were non-steroidal anti-inflammatory drugs (naproxen, diclofenac, and ibuprofen), lipid regulators (clofibric acid), and antibiotics (sulfathiazole, sulfapyridine, sulfamethazine, and sulfamethoxazole). Ultrasound assisted extraction with a water–methanol solvent mixture (1:1, v:v) was performed and the compounds were then determined by liquid chromatography coupled with tandem mass spectrometry. The design of the method was based on the application of the standard addition calibration methodology to reduce matrix interferences. Validation procedures were conducted with rabbit excrements as blank samples. Recoveries of the target analytes ranged from 76 to 131% in spiked samples at 50, 200 or 1000 ng g^?1 dry weight (dw). The relative standard deviations were in the range of 5–15% and the method detection limits ranged from 2 to 12 ng g^?1dw. The method was applied to monitor pharmaceutical concentrations in biosolids from different WWTPs over an eight-month period (May to December 2011). Diclofenac, sulfapyridine and ibuprofen were detected in most of the samples whereas sulfamethazine and ibuprofen were the pharmaceuticals found in the highest concentrations (>200 ng g^?1 dw on average).     

Synthesis and Biological Evaluation of Halogenated E-Stilbenols as Promising Antiaging Agents

The increased risk of illness and disability is related to the age inevitable biological changes. Oxidative stress is a proposed mechanism for many age-related diseases. The crucial importance of polyphenol pharmacophore for aging process is largely described thanks to its effects on concentrations of reactive oxygen species. Resveratrol (3,5,4′-trihydroxy-trans-stilbene, RSV) plays a critical role in slowing the aging process but has a poor bioavailabity after oral intake. In this present work, a series of RSV derivatives was designed, synthesized, and evaluated as potential antioxidant agents. These derivatives contain substituents with different electronic and steric properties in different positions of aromatic rings. This kind of substituents affects the activity and the bioavailability of these compounds compared with RSV used as reference compound. Studies of Log P values demonstrated that the introduction of halogens gives the optimum lipophilicity to be considered promising active agents. Among them, compound 6 showed the higher antioxidant activity than RSV. The presence of trifluoromethyl group together with a chlorine atom increased the antioxidant activity compared to RSV.     

Trace analysis of benzophenone-derived compounds in surface waters and sediments using solid-phase extraction and microwave-assisted extraction followed by gas chromatography–mass spectrometry

This study describes a procedure for determining eight benzophenone-derived compounds in surface waters and sediments. These include the pharmaceutical ketoprofen, its phototransformation products 3-ethylbenzophenone and 3-acetylbenzophenone, and five benzophenone-type ultraviolet (UV) filters. The proposed analytical method involves the pre-concentration of water samples by solid-phase extraction (SPE) and microwave-assisted extraction (MAE) of sediment samples followed by derivatization and analysis by gas chromatography–mass spectrometry. Different parameters were investigated to achieve optimal method performance. Recoveries of 91 to 96 % from water samples were obtained using HLB Oasis SPE cartridges, whereas MAE of sediments (30 min at 150 °C) gave recoveries of 80 to 99 %. Limits of detection were between 0.1 and 1.9 ng L^?1 for water samples and from 0.1 to 1.4 ng g^?1 for sediment samples. The developed method was applied to environmental samples and revealed the presence of UV filters in the majority of the surface waters with up to 690 ng L^?1 of 2-hydroxy-4-methoxybenzophenone. By contrast, ketoprofen (≤2,900 ng L^?1) and its degradation products (≤320 ng L^?1) were found in only two rivers, both receiving wastewater treatment plant effluents. Sediment analysis revealed benzophenone to be present in concentrations up to 650 ng g^?1, whereas concentrations of other compounds were considerably lower (≤32 ng L^?1). For the first time, quantifiable amounts of two ketoprofen transformation products in the aqueous environment are reported.     

Determination of calcium and total hardness in natural waters using a potentiometric sensor array

The determination of calcium and total hardness in natural waters is carried out with a potentiometric sensor array which consists of a series of ion-selective electrodes (ISEs) for Ca²⁺, Mg²⁺, NH₄⁺, K⁺, Na⁺, Li⁺, and H⁺. The selectivity of the calcium and magnesium ISEs is not fully achieved as other cation species may interfere with the analysis. The proposed sensor array device can overcome this drawback since it can take advantage of the cross-selectivities of cation species towards each ISE. In this approach, the multivariate data generated by the sensor array results in a richer source of analytical information which allows the quantification of calcium and total hardness in the water samples by means of chemometric methods. Results obtained are in reasonable concordance with those given by the standard method based on complexometry.     

Microwave-induced multiple functionalization of carbon nanotubes

We describe a new synthetic strategy to produce multifunctionalized carbon nanotubes using a combination of two different addition reactions, the 1,3-dipolar cycloaddition of azomethine ylides and the addition of diazonium salts, both via a simple and fast microwave-induced method. The presence of multifunctionality on the SWNTs has been confirmed using the most useful techniques for the characterization of carbon nanotubes. The doubly functionalized SWNTs can be considered potentially useful for many interesting applications.