Standard molar enthalpy of formation of 1-benzosuberone: An experimental and computational study

The energetics of 1-benzosuberone was studied by a combination of calorimetric techniques and computational calculations.The standard (p° = 0.1 MPa) molar enthalpy of formation of 1-benzosuberone, in the liquid phase, was derived from the massic energy of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The standard molar enthalpy of vaporization, at T = 298.15 K, was measured by Calvet microcalorimetry. From these two parameters the standard (p° = 0.1 MPa) molar enthalpy of formation, in the gaseous phase, at T = 298.15 K, was derived: ?(96.1 ± 3.4) kJ · mol^?1. The G3(MP2)//B3LYP composite method and appropriate reactions were used to computationally calculate the standard molar enthalpy of formation of 1-benzosuberone, in the gaseous phase, at T = 298.15 K. The computational results are in very good agreement with the experimental value.     

Influence of copper hexacyanoferrate film thickness on the electrochemical properties of self-assembled 3-mercaptopropyl gold electrode and application as a hydrazine sensor

A copper hexacyanoferrate film was obtained on a modified electrode prepared by self-assembly of 3-mercaptopropyltrimethoxysilane on a gold surface. The film thickness was controlled using a layer-by-layer technique to tune the electrocatalytic properties of the electrode. Two electrodes with different hexacyanoferrate film thicknesses were prepared via three immersions (AuS/CuHCF3) and six immersions (AuS/CuHCF6) of the film in the precursor solutions. Cyclic voltammetry data were obtained to determine the adequate film thickness. Scanning electron microscopy images showed a roughness increase due to the growth of the film thickness at the electrode surface. Electrochemical impedance spectroscopy showed distinct behavior for the two electrodes prepared; while diffusion and charge transfer processes can be observed in both electrodes, an additional capacitive process at intermediary frequencies was observed for the AuS/CuHCF6 electrode. The charge transfer resistance (R _ct) for the AuS/CuHCF3 electrode (19.6 Ω cm²) was lower than for AuS/CuHCF6 (27.9 Ω cm²) due to the hexacyanoferrate film thickness, since the charge transfer process demands the simultaneous diffusion of K⁺ into the surface. Cyclic voltammetry was used to evaluate the application of the AuS/CuHCF3 electrode as an electrochemical sensor, revealing a linear correlation for hydrazine concentrations.     

Ab initio energetics of nonsubstituted monocyclic pyrones

The monocyclic nonsubstituted pyrones were studied computationally using state-of-the-art ab initio composite computational techniques. Combination of the accurate energies so obtained with conveniently chosen isodesmic or homodesmotic chemical reactions lead to very confident predictions of their corresponding standard enthalpy of formation. The internal consistency of the results obtained from a vast number of independent chemical schemes serves as a further support of the quality of our results, which are thus proposed to establish the energetics of α-pyrone and γ-pyrone.     

Cystoseira algae (Fucaceae): update on their chemical entities and biological activities

Cystoseira (Sargassaceae) is a genus of marine brown algae composed of about 40 species, which is distributed along the Eastern Atlantic and Mediterranean coasts. The biological potential of the Cystoseira genus has been investigated and several activities have been reported. Chemically, this genus contains a wide variety of secondary metabolites, such as terpenoids, steroids, phlorotannins and phenolic compounds. Additionally, other chemical components as, for instance, carbohydrates, triacylglycerols/fatty acids, pigments as well as vitamins have been identified in the studied species. Some of the isolated compounds were associated with the reported pharmacological properties, as for example antioxidant, anti-inflammatory, cytotoxicity, anticancer, cholinesterase inhibition, anti-diabetic, activities but also antibacterial, antifungal and anti-parasitic activities. In this review, we provide a comprehensive overview of the compounds isolated and identified after 1995 from the different species of Cystoseira, compiling more than 200 compounds isolated, together with their therapeutic potential.     

Selective silica‐based sorbent materials synthesized by molecular imprinting for adsorption of pharmaceuticals in aqueous matrices

The presence of pharmaceuticals in aqueous environmental matrices often requires efficient and selective preconcentration procedures. Thus, silicas (SILs) were synthesized by a molecular imprinting technique using an acid‐catalyzed sol‐gel process and the following drugs as templates: fluoxetine, gentamicin, lidocaine, morphine, nifedipine, paracetamol, and tetracycline. The materials were subjected to sorbent extraction assisted by ultrasonic treatment to remove the drugs and the consequent formation of molecular imprinted cavities. The surface area of the resulting materials ranged from 290 to 960 m²/g. Adsorption tests were performed with the molecular imprinting phases. In terms of the potential selectivity, the SILs were subjected to the adsorption of drugs from samples such as potable and surface water. The adsorption capacity remained in the range between 55 and 65% for both matrices, while for the nonimprinted SIL it remained between 15 and 20%.     

Spondias tuberosa (Anacardiaceae) leaves: profiling phenolic compounds by HPLC‐DAD and LC–MS/MS and in vivo anti‐inflammatory activity

Spondias tuberosa is a medicinal plant used by several local communities in northeast Brazil to treat infections, digestive disorders and inflammatory conditions. The study aimed to identify and quantify the major phenolic in hydroethanolic extract of leaves from S. tuberosa and to evaluate its anti‐inflammatory potential. The chemical profile of extract was analyzed by HPLC‐DAD and HPLC–MS. The in vivo anti‐inflammatory activity was investigated in carrageenan‐induced hind paw edema and peritonitis models in mice. Identified and quantified through HPLC‐DAD or HPLC‐MS analyses of S. tuberosa extract were the following compounds: chlorogenic acid, caffeic acid, rutin and isoquercitrin. The inflammatory response to carrageenan was significantly reduced in both models by S. tuberosa extract. In hind paw edema, the edematogenic response was reduced by up to 63.6% and the myeloperoxidase activity was completely inhibited. In the peritonitis model, the total cell migration into the peritoneal cavity was reduced by up to 65%. The results obtained give evidence of the anti‐inflammatory action of S. tuberosa and suggest the potential therapeutic benefit of this plant on inflammatory conditions. The chlorogenic acid, caffeic acid, rutin and isoquercitrin identified and quantified in S. tuberosa leaves enable us to suggest that these compounds could be used as chemical markers for quality control of derivative products from this species. Copyright © 2016 John Wiley & Sons, Ltd.