Transformation of ionic liquid into carbon nanotubes in confined nanospace

We have developed a two-step filling process for the nano-reaction of ionic liquid in a tip-closed SWNT, where fullerenes are inserted at the end of the host SWNT as a plug to prevent the leakage of the confined ionic liquid during heat treatment.     

Unambiguously confirmed structure of 2-phenacylidene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one and 3-phenacylidene-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one

To determine the structures of two isomeric products, 2-phenacylidene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (2) and 3-phenacylidene-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (3) obtained by condensation of 2,3-diaminopyridine (1) with ethyl benzoylpyruvate [1–3], these compounds were hydrolyzed to give 2-methyl-4H-pyrido[2,3-b]pyrazin-3-one (4) and 3-methyl-1H-pyrido[2,3-b]pyrazin-2-one (5) , respectively [4,5]. Both hydrolysates 4 and 5 were hydrogenated to afford 2-methyl-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (6) and 3-methyl-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (7) . The latter compound was identical with an unequivocally synthesized compound providing proof for the structures of all these compounds.     

Cytotoxicity of asymmetric platinum complexes against L-1210 cells. Effect of bulky substituents

The asymmetric platinum complexes cis-Pt(LL')Cl2 (L = NH3, L' = CH3NH2, (CH3)2NH, C2H5NH2 and (C2H5)2NH and LL' = N,N-dimethylethylenediamine),--one of the NH3 groups of cis-Pt(NH3)2Cl2 was substituted by alkylamine--, were synthesized and their cytotoxic effects have been measured using L-1210 cells. The IC50 values of the asymmetric platinum complexes,--being obtained after 24 h exposure of L-1210 cells to the platinum complexes--, are almost comparable to the corresponding value of cis-Pt(NH3)2Cl2. In 2 h exposure, however, the IC50 values of the platinum complexes were dramatically changed, i.e., a marked difference was observed between those of L' = RNH2 and L' = R2NH. On the other hand, the amounts of platinum taken into the L-1210 cells is little affected by the alkylamino substitution. The results suggest that the bifunctional platinum binding to the target molecule may be responsible for the cytotoxicity.     

Ionic liquid synergistic cation-exchange system for the selective extraction of lanthanum(III) using 2-thenoyltrifluoroacetone and 18-crown-6.

A novel synergistic extraction system was investigated for the possible selective separation of light lanthanoids using an ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, as an extraction solvent and 2-thenoyltrifluoroacetone and 18-crown-6 as extractants. Trivalent lanthanum was efficiently extracted as a cationic ternary complex by the cation-exchange process, whereas europium and lutetium showed relatively low extractability without forming respective ternary complexes. This result is thought to originate in a size-fitting effect of 18-crown-6 to lanthanum and the unique nature of the ionic liquid as a chelate extraction solvent.     

Electrical conductivity of cytochrome c anhydrous film

Electrical conducitivities of both ferricytochrome c and ferrocytochrome c anhydrous films were measured at physiological temperatures. A film-casting method was applied to prepare the films. Rather low values of resistivities (55°C) of 6.5 × 10¹⁰ Ω cm for ferrocytochrome c in comparison with the previously reported value of 10¹¹ Ω cm (127°C) were obtained. Apparent activation energies for the above conductivities, 0.6 eV, were the same in both samples.     

Electroproduction of π from C leading to low-lying residual states in B

Energy distributions of π⁺ produced from ¹²C by electrons of total energy 195 MeV were measured at various angles. The results show large contributions from transitions leaving the residual nucleus in the ground (1⁺), first (2⁺) excited state and states at around 4.5 MeV. The angular distributions of ¹²C(γ, π⁺)¹²B leading to these residual states are deduced from the energy distributions by the unfolding method with the virtual photon theory. Theoretical results with the Helm model and the shell model are compared with the experimental results. Their relative shapes are in good agreement. A better agreement in the absolute value is found for the theoretical results which include the final-state interaction estimated with a pion optical potential. The surface production model shows better agreement with the experimental (γ, π⁺) cross sections than the volume production model.     

Application of hydride generation to the determination of trace concentrations of arsenic by inductively-coupled plasma atomic emission spectrometry

A method is described for the determination of traces of arsenic, based on sodium tetrahydroborate reduction of arsenic and introduction of the arsine formed to a relatively low-powered (1.6 kW) inductively-coupled plasma where the arsenic atomic emission is generated, Inter-element interference effects are described; many can be eliminated by addition of potassium iodide to the sample solutions, but the standard additions method is recommended for accurate arsenic determination. Potassium iodide is also used for prereducing arsenic(V) to arsenic(III). The method has a detection limit of 0.1 ng As ml^-1 and the linear calibration range spans nearly four orders of magnitude. The proposed method is applied to the determination of ng ml^-1 levels of arsenic in waste waters.     

121Sb Mössbauer spectroscopic study on electronic states of pentavalent organoantimony compounds

A systematic study of pentavalent organoantimony compounds, (RC₆H₄)₃SbX₂ (R=H,p-CH₃,p-F,p-Cl,p-CF₃,o-CH₃; X=Cl, Br), was carried out to examine the effect on Mössbauer parameters of the substituent on the aromatic ring. The Mössbauer parameters obtained in polycrystalline form reflected the steric effect caused by the position of the substituent on the aromatic ring. On the other hand, measurements in frozen organic solutions revealed that the electron density and electric field gradient at and around the antimony nucleus became smaller when the more electron-attractive group was introduced into thepara position.     

Photodissociation of molecular beams of halogenated hydrocarbons at 193 nm

Molecular beams of halogenated hydrocarbons containing chlorine and bromine atoms were photodissociated using an excimer laser at 193 nm. Molecules photodissociated were HCCBr, HCCCH₂Br, HCCCH₂Cl, CH₃Cl, C₂H₅Cl and i-C₃H₇Cl. The time-of-flight distributions of the photofragments were measured in order to study the primary processes and the dissociation dynamics. Generalizations consistent with the data are that atomic products (RX → R + X) result from direct dissociation of the CX repulsive singlet state, molecular elimination (RX → R′ + HX) is a result of a crossover to the ground state and triplet states are involved in the photodissociation of alkyne compounds.