Visible-light-mediated selective thiocyanation/ipso-cyclization/oxidation cascade for the synthesis of thiocyanato-containing azaspirotrienediones

A visible-light-mediated metal-free thiocyanate radical addition/ipso-cyclization/oxidation cascade reaction for the synthesis of thiocyanato-containing azaspirotrienediones from N-phenylpropynamides is described. Cheap and readily available ammonium thiocyanate was used as a precursor to the thiocyanate free radical, which undergoes a radical addition reaction with the alkyne, followed by selective ipso-cyclization and oxidation to afford the dearomatized products. No product of ortho-cyclization was detected. The reaction completes the synthesis of C–S, C–C, and CO bonds in one pot, with abundant and renewable air oxygen as the sole sacrificial reagent and oxygen source.     

A new rapid ultra‐performance liquid chromatography method for the pharmacokinetic and bioavailability study of diclofenac sodium aqueous injection and lipid microsphere injection in rats

A novel, rapid and selective ultra performance liquid chromatography mass spectrometric method had been developed for the pharmacokinetic study of diclofenac sodium (DS) after single intravenous injection of DS aqueous injection and DS lipid microsphere (LM) injection in rats. Ketoprofen (KP) was used as internal standard. Samples were treated by a one‐step liquid liquid extraction. Separation was performed on an Acquity UPLC? BEH C₁₈ column (50 × 2.1 mm i.d., 1.7 μm). The mobile phase consisted of acetonitrile–0.1% ammonium hydroxide aqueous solution (20 : 80, v/v) initially in the gradient mode. The detection was carried out by means of electrospray ionization mass spectrometry in negative ion mode with multiple‐reaction monitoring mode. Standard curves showed good linearity (r > 0.99) from the plasma concentration of 0.1–50 μg/mL. The lower limit of quantification was 0.1 μg/mL. The intra‐ and inter‐day precisions and the accuracy all satisfied the acceptance criteria. The developed method was validated and successfully applied to the pharmacokinetics study of DS aqueous injection and LM injection. The results showed that the two preparations were bioequivalent in rats. Copyright © 2009 John Wiley & Sons, Ltd.     

Preparation and time-gated luminescence bioimaging application of ruthenium complex covalently bound silica nanoparticles

Luminescent ruthenium(II) complex covalently bound silica nanoparticles have been prepared and used as a probe for time-gated luminescence bioimaging. The new nanoparticles were prepared by copolymerization of a luminescent Ru(II) complex tris(5-amino-1,10-phenanthroline)ruthenium(II) conjugated with 3-aminopropyl(triethoxy)silane (APS-Ru conjugate), free (3-aminopropyl)triethoxysilane (APS) and tetraethyl orthosilicate (TEOS) in a water-in-oil reverse microemulsion consisting of Triton X-100, n-octanol, cyclohexane and water in the presence of aqueous ammonia. Characterization by transmission electron microscopy indicates that the nanoparticles are monodisperse, spherical and uniform in size, 64 ± 4 nm in diameter. Compared with the dye-doping nanoparticles, dye leakage of the new nanoparticles was remarkably decreased. In addition, it was found that the Ru(II) complex luminescence could be effectively enhanced with a longer luminescence lifetime (∼2.3 μs) after forming the nanoparticles, which enables the nanoparticles to be suitable as a bioprobe for time-gated luminescence bioimaging applications. The nanoparticle-labeled streptavidin was prepared and successfully used for time-gated luminescence imaging detection of an environmental pathogen, Giardia lamblia, with high specificity and sensitivity.     

Gear-like array of （H2O）12 as building blocks one-dimensional supramolecular assembly

The preparation and crystal structure of complex Co（Hsae）2·2H2O （1, H2sae = N-salicylidene-2-iminoethanol） are reported. X- ray analysis revealed that every six Co（Hsae）2 forms a cyclic chip and every 12 water forms a novel gear-like cluster. Acting as building blocks, the gear-like water cluster and complex chip are connected in A-B fashion and extend into one-dimensional supramolecular chain. Hydrogen bond is the primary bridging force in the formation of supramolecular framework.     

Synthesis of transition-metal phosphides from oxidic precursors by reduction in hydrogen plasma

A series of transition metal phosphides, including MoP, WP, CoP, Co₂P, and Ni₂P, were synthesized from their oxidic precursors by means of hydrogen plasma reduction under mild conditions. The effects of reduction conditions, such as metal to phosphorus molar ratio, power input, and reduction time, on the synthesis of metal phosphides were investigated. The products were identified by means of XRD characterization. It is indicated that metal phosphides were readily synthesized stoichiometrically from their oxides in hydrogen plasma under mild conditions.     

Density Functional Studies of Diatomic LaO to LuO

Bond distances, vibrational frequencies, electron affinities, ionization potentials, dissociation energies and dipole moments of the title molecules in neutral, positively and negatively charged ions were studied by use of density functional method. Ground electronic state was assigned for each molecule. The bonding patterns were analyzed and compared with both the available data and across the series. It was found that besides ionic component, covalent bonds are formed between the metal s, d and f orbitals and oxygen p orbitals. Contrary to the well known lanthanide contraction, the bond distance is not regular from LaO to LuO for both neutral and charged molecules. An obvious population at 5d orbital was observed through the lanthanide series. 4f electrons also participate the chemical bonding for CeO to NdO and TbO to TmO. For EuO, GdO, YbO and LuO, 4f electrons tend to be localized. The spin multiplicity is regular for neutral and charged molecules. The spin multiplicity of the charged molecules can be obtained by −1 (or +1 for TbO⁺, DyO⁺, YbO⁻ and YbO⁺) compared with the corresponding neutral molecules.