Mercaptopropylsilatrane (MPS) was investigated as a novel self-assembled film on silica surfaces and also as a novel adhesive layer for the construction of a gold colloid monolayer on silica surfaces.

Surface modification of a polymer substrate with a mercapto functionality is crucial in many applications such as flexible circuitry and point-of-care biosensors. We present here a novel bifunctional molecular adhesive, 3-mercaptopropylsilatrane (MPS), as an interface between polymer and metal surfaces. Under ambient conditions, surface modification of polymer surfaces with a mercapto functionality can be achieved with low concentration (0.46 mM) of MPS in aqueous solvent (50% ethanol) in a short time (<30 min). Three popular polymers for optical sensors, polycarbonate, polyethylene terephthalate, and poly(methyl methacrylate), were employed as substrates, and MPS films formed on these substrates were examined and compared with that on a glass substrate. The films were characterized by UV-vis spectroscopy, water contact angle, X-ray photoelectron spectroscopy, and atomic force microscopy. MPS was also used as a bifunctional linker for the construction of a gold nanoparticle (AuNP) sub-monolayer on these polymer surfaces. Under optimized preparation conditions, the absorbance and full width at half-maximum of the plasmon band are comparable to those of a AuNP-modified glass substrate. Hence, MPS may have a potential to be a key component in polymer substrate-based localized surface plasmon resonance sensors. A self-catalytic surface reaction mechanism is also proposed to account for the results. As compared to a glass surface with a high number of silanol groups, the successful formation of an MPS film on polymer surfaces with relatively few reactive sites is probably due to the lateral polymerization of MPS starting from a condensed MPS molecule on a reactive site of a polymer surface.

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There are more than 20 species of Oxytropis distributed in different regions of China. Most of the Oxytropis species are highly poisonous to livestock. For sheep and cattle, lengthy exposure will result in chronic intoxication with such symptoms as emaciation, acyesis, abortus, still birth or abnormalities, and may even cause death. To establish biomedical applications of the poisonous species, a careful phytochemistry investigation of the roots of Oxytropis falcata Bunge collected in China in 2006, was carried out by our group.The air-dried roots of O. falcata (0.5 kg) were extracted three times (each for 7 days) successively with EtOH at room temperature. The resultant extract was concentrated under reduced pressure to yield a residue (90 g), which was suspended in water and fractionated by successive partitioning with petroleum ether (60 -90˚C), EtOAc and 1-BuOH. The EtOAc fraction (10 g) was subjected to repeated column chromatography. The title compound (20 mg), as one of the components, was isolated. The NMR and MS spectroscopy analysis of this compound disclosed its isoflavanquinonic skeleton and pattern of substitution, which was determined to be 7-hydroxy-3¢,4¢-dimethoxyisoflavanquinone, the first report of isoflavanquinone from this genus, previously identified as pendulone. 1 However, the absolute configuration remained unknown. The CD spectrum of pendulone, correlated with that of (3R)-Astragaluquinone, 2 exhibited a positive cotton effect in the 270 -300 nm region. Thus, pendulone was defined unambiguously by its 3R absolute stereochemistry.Leishmaniasis is endemic in tropical regions, currently prevalent throughout the world, and in at least 88 countries. 3 In a previous investigation, pendulone exhibited remarkable in vitro antileishmanical activity with an IC50 value of 0.07 mg/ml. 4The interesting biological activity of the title compound has stimulated efforts toward a detailed X-ray analysis to disclose its inherent three-dimensional structure, and has provided scientists with tools to understand the biological mechanisms of action and to develop animal models for human diseases.Red crystals suitable for an X-ray structural analysis were obtained by slowly evaporating from a petroleum ether-acetone solution at room temperature. The crystal and experiment data are given in Table 1. The structure was solved by direct methods and refined with anisotropic temperature factors for non-H atoms. All H atoms, except for that of the hydroxyl group, which was found from difference Fourier maps, were calculated geometrically. The atomic parameters of the non-hydrogen The complete structure of the title compound, C17H16O6, isolated from the roots of Oxytropis falcata Bunge, was confirmed unambiguously by a single-crystal X-ray analysis. The absolute configuration was established by circular dichroism (CD). The bond distances and angles are within the expected ranges. The quinone ring is linked to the chroman ring by C(3) at an equatorial position. The crystal structure is also stabilized by intermolecular ...

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