The first ruthenium-alkyne-dihydride reported is now recognized as an intermediate in the homogeneous hydrogenation of diphenylacetylene: Crystal structure of (μ-H)2Ru3(CO)9(μ3-η2-∥-C2Ph2)

The title complex (complex1) was the first alkyne-substituted triruthenium dihydrido cluster to be reported and was characterized by spectroscopy as a triangular cluster with the alkyne parallel to a Ru-Ru edge. Recently, we have found that1 is a key intermediate in the homogeneous hydrogenation of diphenylacetylene catalyzed by tetrahedral Ru₄ and FeRu₃ clusters. Since the discovery of1, a great number of complexes with alkynes parallel to a cluster edge have been reported; at present this is the more common bonding mode for alkynes on trinuclear clusters. The structural features of1 allow a comparison with those of other ruthenium-containing derivatives and help to draw suggestions of the role of1 in hydrogenation catalysis.     

Effect of Extraction Methods and In Vitro Bio-Accessibility of Microencapsulated Lemon Extract

The extraction of bioactive compounds from fruits, such as lemon, has gained relevance because these compounds have beneficial properties for health, such as antioxidant and anticancer properties; however, the extraction method can significantly affect these properties. High hydrostatic pressure and ultrasound, as emerging extraction methods, constitute an alternative to conventional extraction, improving extractability and obtaining extracts rich in bioactive compounds. Therefore, lemon extracts (LEs) were obtained by conventional (orbital shaking), ultrasound-assisted, and high-hydrostatic-pressure extraction. Extracts were then microencapsulated with maltodextrin at 10% (M10), 20% (M20), and 30% (M30). The impact of microencapsulation on LEs physicochemical properties, phenolics (TPC), flavonoids (TFC) and relative bio-accessibility (RB) was evaluated. M30 promoted a higher microencapsulation efficiency for TPC and TFC, and a longer time required for microcapsules to dissolve in water, as moisture content, water activity and hygroscopicity decreased. The RBs of TPC and TFC were higher in microcapsules with M30, and lower when conventional extraction was used. The data suggest that microencapsulated LE is promising as it protects the bioactivity of phenolic compounds. In addition, this freeze-dried product can be utilized as a functional ingredient for food or supplement formulations.     

The Binary Oxide System TeO2?MoO3

Phase analysis of the mixed oxide system TeO₂? MoO₃ by means of x-ray diffraction and optical microscopy indicates the formation of a new phase, α-Te₂MoO₇, stable at room temperature. Below 500°C mixtures of crystalline products are obtained or complete devitrification can easily be induced in the system TeO₂? MoO₃. Above this temperature, tendency to glass formation is observed under the conditions employed, due to the liquidus temperature effect. Quenching of a melt of Te₂MoO₇ yields a dark yellow glass, α-Te₂MoO₇. X-ray and density measurements were used to explore the range of stoichiometry and exclude formation of solid solutions in the system; no apparent relationship exists between the crystal structures of the component oxides and the binary compound.     

The spiropiperidine-3,3′-oxindole scaffold: a type II β-turn peptide isostere

An unprecedented chiral spiropiperidine oxindole system was synthesized starting from enantiopure quaternary 3-aminooxindole and relying on a ring closing metathesis as the key step. This compound acts as an highly constrained Freidinger γ-lactam, adopting a type II β-turn conformation in solution, as assessed by modelling and spectroscopical studies.