Synthesis of 5,10,15-triazaporphyrins--effect of benzo-annulation on the electronic structures

Novel triazaporphyrins were synthesized using 1,9-dibromodipyrromethene as a key starting material. These triazaporphyrins exhibit comparatively intense Soret and Q bands in the UV/vis region due to their hybrid properties between porphyrins and phthalocyanines.     

Ag(I) ion mediated formation of a C-A mispair by DNA polymerases

Silver turns up the A-C: In the presence of Ag(I) ions, a DNA polymerase incorporated deoxyadenosine (from dATP) at the site opposite cytosine in the template strand to afford the full-length product (see scheme), meaning that DNA polymerases prefer a C-Ag(I)-A base pair to the more thermodynamically stable C-Ag(I)-C base pair.     

Andirolides H–P from the flower of andiroba (Carapa guianensis,Meliaceae)

Three new gedunins, an andirobin, three mexicanolides, and two phragmalin-type limonoids named andirolides H (1), I (2), J (3), K (4), L (5), M (6), N (7), O (8), and P (9) were isolated from an oil of the flower of Carapa guianensis Aublet (Meliaceae). Their structures including the absolute configurations were determined by means of the NMR and CD spectra as well as FABMS. Andirolide H (1) showed antimalarial activity against Plasmodium falciparum in vitro.     

Rupestines F-M, new guaipyridine sesquiterpene alkaloids from Artemisia rupestris

Eight new guaipyridine sesquiterpene alkaloids, rupestines F-M (1-8) were isolated from the leaves of Artemisia rupestris and their structures were elucidated on the basis of 2D-NMR data. The absolute configurations of 1-8 have been assigned by comparison of their experimental and calculated circular dichroism (CD) spectra.     

Crystal structure of 1,10-dibromodecane and its infrared intensity in a urea clathrate and in the crystal

The crystal structure of 1,10-dibromodecane belongs to the monoclinic system and the space group is P2(1)/c with lattice dimensions of a = 5.4574(3) A, b = 5.2814(4) A, c = 21.088(1) A and beta = 92.897(2) degrees and zeta = 2. Infrared spectra of 1,10-dibromodecane in a urea clathrate and in the crystal were observed to investigate the effect of molecular interaction on infrared intensity. The infrared intensity of the CH(2) waggings in the crystalline state is 1.5-1.9 times stronger on the relative basis than that in a urea clathrate, whereas those of CH(2) stretching, CH(2) rocking and CH(2) bending are almost the same in both states. The former enhancement is explained in terms of increase in the bond moment of the C(alpha)H(2) group on the basis of crystal structure and the electrostatic model. The relative intensity of two CH(2) asymmetric stretching changes between the two states. This is also analyzed by the use of the electrostatic model.     

Photocatalytic water splitting using modified GaN:ZnO solid solution under visible light: long-time operation and regeneration of activity

Overall water splitting using GaN:ZnO solid solution photocatalyst modified with Rh(2-y)Cr(y)O(3) nanoparticles as H(2) evolution cocatalysts under visible light (400 < λ < 500 nm) was examined with respect to long-term durability and regeneration of photocatalytic activity. The rate of visible light water splitting remained unchanged for 3 months (2160 h), producing H(2) and O(2) continuously at a stoichiometric amount. After 6 months of operation, a 50% loss of the initial activity occurred. Regeneration treatment of deactivated catalysts was attempted by reloading the Rh(2-y)Cr(y)O(3) cocatalyst. The degree of activity regeneration depended on the reloading amount. Up to 80% of the initial activity for H(2) evolution could be recovered under optimal treatment conditions. It was also found that deactivation of GaN:ZnO was suppressed to some extent by prior coloading of an O(2) evolution cocatalyst, which helped to suppress oxidative decomposition of GaN:ZnO by valence band holes, thereby improving the durability.     

Moment maps associated with holomorphic isometric actions on K?hler manifolds

We give a new formula which writes down the moment map for holomorphic isometric action on a K?hler manifold using the motion of a charged particle when the action of is Hamiltonian.     

Molecularly imprinted solid-phase extraction for the selective determination of methamphetamine, amphetamine, and methylenedioxyphenylalkylamine designer drugs in human whole blood by gas chromatography-mass spectrometry

A novel method is described for the extraction of methamphetamine, amphetamine, and methylenedioxyphenylalkylamine designer drugs, such as 3,4-methylenedioxy-methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxyethylamphetamine, N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine, and 3,4-(methylenedioxyphenyl)-2-butanamine, from human whole blood using molecularly imprinted solid-phase extraction as highly selective sample clean-up technique. Whole blood samples were diluted with 10 mmol/L ammonium acetate (pH 8.6) and applied to a SupelMIP-Amphetamine molecularly imprinted solid-phase extraction cartridge. The cartridge was then washed to eliminate interferences, and the amphetamines of interest were eluted with formic acid/methanol (1:100, v/v). After derivatization with trifluoroacetic anhydride, the analytes were quantified using gas chromatography-mass spectrometry. Recoveries of the seven amphetamines spiked into whole blood were 89.1-102%. The limits of quantification for each compound in 200 μL of whole blood were between 0.25 and 1.0 ng. The maximum intra- and inter-day coefficients of variation were 9.96 and 13.8%, respectively. The results show that methamphetamine, amphetamine, and methylenedioxyphenylalkyl-amine designer drugs can be efficiently extracted from crude biological samples such as whole blood by molecularly imprinted solid-phase extraction with good reproducibility. This extraction method will be useful for the pretreatment of human samples before gas chromatography-mass spectrometry.     

Coupling plasmons and dyakonons

We study the coupling of plasmons and Dyakonov surface waves propagating at the interfaces between isotropic-birefringent-metal layered structures. Efficient coupling is shown to occur with a proper choice of the crystal birefringence, the refractive index of the isotropic medium, and the light propagation direction relative to the crystal optical axis. In the case of low-loss metals, coupling efficiencies as high as 90% are predicted to be possible.