Supramolecular design of a porphyrin-[60]fullerene photocurrent generation system on a DNA scaffold fabricated by a conjugate polymer film

DNA which binds monocationic [60]fullerene (1) and tetracationic porphyrin (TMPyP) was readily fabricated by electrochemical oxidative polymerization of 3.4-ethylenedioxythiophene (EDOT) and the resultant poly(EDOT) composite was deposited on an ITO electrode as a stable thin film. Spectral and CV analyses established that one 1 and one TMPyP are bound per 57 nucleobase units, that is, every three pitches of DNA. Photoirradiation of this 1/TMPyP/DNA-poly(EDOT) film generated a photocurrent in 3.8% quantum yield, which was much higher than those obtained from 1/DNA and TMPyP/DNA systems. One can conclude, therefore that the photoexcited energy of TMPyP is transferred to 1, which is collected by the electron-conducting poly(EDOT) film. The present paper shows that DNA is useful as a scaffold to arrange redox-active couples in a one-dimensional matrix.     

Synthesis of novel cyclic sulfilimines, 2-azathiabenzene derivatives

The synthesis and some properties of novel cyclic sulfilimines, 2-methyl-1-aza-2-thianaphthalene and 9-methyl-10-aza-9-thiaphenanthrene are described.     

Preparation of functionally Pegylated gold nanoparticles with narrow distribution through autoreduction of auric cation by alpha-biotinyl-PEG-block-[poly(2- (N,N-dimethylamino)ethyl methacrylate)

PEGylated gold nanoparticles with biotin moieties installed at the distal end of the PEG tethered chains were prepared by the autoreduction of HAuCl4 catalyzed by alpha-biotinyl-PEG-block-poly[2-(N,N-dimethylamino)ethyl methacrylate] (biotinyl-PEG/PAMA) in aqueous medium at room temperature. The size of the gold nanoparticles was controllable in a range of 6-13 nm by changing the initial Au3+/polymer ratio, while retaining their narrow size distribution. The dispersion stability of the nanoparticles in aqueous medium was extremely high even under the condition of salt concentration as high as I = 2.0. Biotinyl-PEG/PAMA-anchored gold nanoparticles underwent specific aggregation in the presence of streptavidin, revealing their promising utility as colloidal sensing systems applicable under biological condition.     

One-pot preparation of mono-dispersed and physiologically stabilized gold colloid

We have developed a rapid and simple method for the preparation of nearly mono-dispersed gold colloids with a fairly high concentration above 10 mM using hydroxylamine as the reducing agents, in the presence of α-methoxy-ω-mercaptoethyl-poly(ethylene glycol)(MeO-PEG-SH). It was found that a hydroxylamine acted not only as a reducing agent, but also as a nucleation agent under alkaline reaction conditions. Though the colloid concentration was fairly high, the dispersion stability was remarkably improved even in a high ionic strength in the range greater than 1 M NaCl, in which conventional citrate gold colloids immediately flocculate and precipitate. The obtained colloid was successfully re-dispersed in aqueous media after lyophilization. In addition, the prepared gold colloid reduced a protein adsorption significantly on its surface. Concerning these results, the obtained colloidal dispersion may be suitable for biological applications, since a regionally concentrated colloidal dispersion with dispersion stability is required for bio-labeling and bio-imaging systems.Electronic Supplementary Material Supplementary material is available for this article at     

'Nucleo-nanocages': designed ternary oligodeoxyribonucleotides spontaneously form nanosized DNA cages

DNA three-way junctions formed from three 30-mer oligonucleotides that contain single-chained self-complementary sticky ends spontaneously self-assemble into 'nucleo-nanocages': the exo- and endo-nuclease digestion experiments indicate that defects such as the single and double strand end structures are absent on the spherical nano-assemblies, providing clear evidence for the closed nanocage structure.     

Separation of stereoisomers of several furan derivatives by capillary gas chromatography-mass spectrometry,supercritical fluid chromatography,and liquid chromatography using chiral stationary phases

The direct separation of several stereoisomers (enantiomers and geometrical isomers) of furan derivatives, important intermediates for the synthesis of physiologically active natural products, was achieved using capillary gas chromatography/mass spectrometry with a per-O-methyl-beta-cyclodextrin, supercritical fluid chromatography and high-performance liquid chromatography with a tris(3,5-dimethylphenylcarbamate) of cellulose or amylose for the chiral stational phases, respectively. The temperature dependence of the peak resolution (Rs) and the retention factor (k) over the range of 110-130 degrees was studied using crotyl furfuryl ether in gas chromatography. Successive increases in the Rs value and of the difference between the k value of the E-isomer and the k value of the Z-isomer were observed when the gradient temperature was decreased. The per-O-methyl-beta-cyclodextrin column was suitable for use with volatile furan ethers whose molecular masses are between 150 and 180. In conclusion, the separation of thermally unstable furan derivatives was accomplished using supercritical fluid chromatography and high-performance liquid chromatography.     

Preparation and characterization of nickel(II), copper(II) and palladium(II) complexes with 5,14-dihydro-7,16-diethyl-dipyrazo[b,i][1,4,8,11]tetraazacyclotetradecine

A novel macrocycle, 5,14-dihydro-7,16-diethyldipyrazo[b,i][1,4,8,11]tetraazacyclotetradecine, has been synthesized from 1,2-diaminopyrazine and 2-ethyl-3-ethoxyacrolein. The absorption bands appearing in the energy range greater than 20000 cm^?1 were attributable to the π → π transitions. The bands in the range of the 20100–23300 cm^?1 show more bathochromic shift and greater intensity than those observed for corresponding 5,14-dihydro-7,16-diethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine and/or 5,14-dihydro-7,16-diethyl-(Z)-dipyrido[b,i][1,4,8,11]tetraazacyclotetradecine. The nickel(II), copper(II) and palladium(II) complexes of 5,14-dihydro-7,16-diethyldipyrazo[b,i][1,4,8,11]tetraazacyclotetradecine have been synthesized using a metal template reaction. In ¹H and ¹³C nmr spectra, the signals of annulene skeleton for metal-free ligand and its complexes were found to observe in the lower field than those of the dibenzoanalogue.     

Synthesis of the enantiomers of 1,7-dioxaspiro[5.5]undecane, 4-hydroxy-1,7-dioxaspirol[5.5]undecane and 3-hydroxy-1,7-dioxaspiroi[5.5]undecane : The components of the olive fruit fly pheromone

All of the enantiomers of the title compounds, the components of the pheromone of the olive fruit fly ($\text{Dacus}$$\text{oleae}$ Gmelin), were synthesized from ($\text{S}$)-malic acid.     

Microwave spectrum,structure, dipole moment and internal rotation of trans-ethylmethylether

Microwave spectra of ethylmethylether and its eleven isotopically substituted species were measured. The r_s structure of the trans isomer was determined from the observed moments of inertia. Structural parameters of this isomer were roughly equal to those of the reported r_s structure for dimethylether and diethylether. The CH₂-O bond length was definitely shorter by about 0.01 Å than the CH₃-O bond length and the C-C bond length was nearly equal to those of ethylchloride and bromide. The OCH₃ group tilted by about 2° 13' towards lone pair electrons of the oxygen atom while no significant tilt angle was found for the CH₃C group.Dipole moments of the trans isomer for the normal and two deuterated species were determined by Stark-effect measurements. For the normal species, the dipole moment was μ_a = 0.146 ± 0.022 D,μ_b = 1.165 ± 0.020 D and μ_total=1.174 ± 0.022 D making an angle of 7° 5' ± 32' with the b inertial axis. Direction of the dipole moment in the molecule was discussed.From splittings of the observed spectra, barriers to internal rotations of two CH₃ groups were obtained in the one-top approximation. They were 2702 ± 7 and 3300 ± 25 cal mol^?1 for the OCH₃ and CH₃C groups, respectively, from the analysis of splittings in the first excited CH₃ torsional states. The coupling effects among two tops and the skeletal torsion were briefly discussed.     

Optimal Hylleraas wave functions

Hylleraas wave functions composed of the optimally combinedN terms (2 N 20) are presented for two-electron atoms with nuclear chargesZ = 1 (H^–), 2(He), 3(Li⁺), 5(B³⁺), and 10(Ne⁸⁺). The spherically-averaged electron density (r) and electron-pair densityh(r ₁₂) are constructed in a simple and analytical functional form from the 20-term functions. Comparison of several one- and two-electron moments r ^k and r ₁₂ ^k shows that the present density functions have near-exact accuracy.