Synthesis, reactivity, and properties of N-fused porphyrin manganese(I) tricarbonyl complexes

The reactions of N-fused tetraphenylporphyrin (NFTPP, 1a) and its 21-substituted derivatives, 21-Br-NFTPP (1b), 21-NO(2)-NFTPP (1c), and 21-Bz-NFTPP (1d), with Mn(CO)(5)Br gave the manganese(I) tricarbonyl complexes bearing N-fused tetraphenylporphyrinato ligands (2a-d), respectively, in 46-99% yields. The complexes were characterized by mass, IR, (1)H and (13)C NMR spectroscopy, and the final structural proof was evident from the X-ray crystallographic analysis for 2a. The crystals of 2a·CH(2)Cl(2) belong to the monoclinic space group P2(1)/n (#14), with a = 15.007(2) ?, b = 12.5455(19) ?, c = 21.150(3) ?, β = 102.227(4)°, and Z = 4. The lengths (?) of three manganese-nitrogen and three manganese-carbon bonds are inequivalent respectively [Mn-N(2), 2.007(2); Mn-N(23), 2.033(2); Mn-N(24), 1.988(3); and Mn-CO, 1.798(4), 1.804(4), 1.841(3)], reflecting the asymmetric structure of the NFp ligand. The aromatic substitution reactions of 2a, such as nitration, formylation, and chlorination, proceeded without a loss of center metal to give the corresponding 21-nitro (2c), 21-formyl (2e), and 21-chloro (2f) derivatives, regioselectively. In the electrochemical measurements of 2, one reversible oxidation and two reversible reduction waves were observed. The redox potentials of 2 indicate the narrow energy gaps between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO) being consistent with the electronic absorption spectra that display the absorption edges over 1000 nm. Protonation occurred at the inner core nitrogen of 2a upon the addition of acids, which is inferred from the (1)H NMR spectra as well as theoretical calculations. By a treatment with amine N-oxides, demetalation of 2 proceeded to afford the corresponding NFP free-bases (1).     

Transformation of peptide nanotubes into a vesicle via fusion driven by stereo-complex formation

Two types of peptide nanotubes, one is prepared from an amphiphilic peptide having a right-handed helix segment and the other from that having a left-handed helix segment, are shown to transform the morphology into a vesicle by membrane fusion due to stereo-complex formation between these helical segments.     

Electronic structures of Laves phase compounds

The electronic structures of Laves phase compounds AB₂ (A = Y, Zr, Nb; B = Cr, Mn, Co, Ni) were investigated systematically by the LMTO method within the framework of the LSD approximation. Comparing the calculated total energy for hypothetical para-, ferro-, and antiferromagnetic state with the C14 and the C15 structure, the theoretical predictions are in good agreement with the experiments concerning the stability of the crystal structure and the magnetism. The magnetic stability critically depends upon the change of the lattice spacing, which leads to the colorful behaviors of the magnetism in Fe Laves phase compounds and the anomalous volume change in the antiferromagnetic state of YMn₂.     

Development of copolymer of CR-39 with high sensitivity to low let particles

Several types of copolymers of CR-39 were prepared to find its usefulness as a nuclear track detector of high sensitivity. Track responses of these copolymers were investigated by irradiating energetic ions from proton through Ar. The copolymer of CR-39 monomer with N-isopropylacrylamide (NIPAAm) shows higher sensitivity than that of pure CR-39 for low LET particles such as protons. Preliminary results are reported for the track responses of copolymers (CR-39/NIPAAm) with various contents of NIPAAm as well as the etching properties.     

A practical method for monitoring <Superscript>129</Superscript>I concentration in airborne release

Summary To establish a practical method for monitoring ¹²⁹I concentration in airborne release from the Tokai reprocessing plant, the ¹²⁹I collecting performance of sampling media used was tested by in situ experiments. The results indicated that the combined use of an activated charcoal-impregnated filter paper and an activated charcoal cartridge gives a collection efficiency of more than 90% for a one-week sampling of real airborne effluent, at sampling flow rates of 40.6-75.0 l^. min^-1. The sampling and measurement conditions suitable for a routine-base monitoring are demonstrated.     

The nitroalkene showing dual behaviors in the same reaction system

The nitroalkene moiety of 1-methyl-3,6,8-trinitro-2-quinolone showed dual behaviors in the same reaction system, namely electron-poor heterodiene and dienophile, and affording polycyclic products.     

Blood volume measurement of newborn using stable isotope 50Cr

A technique for the blood volume measurement of newborns was established in which nonradioactive 50Cr was used in patients for whom radioactive labels were not advisable. The red blood cells (RBC) in the newborn's blood withdrawn from umbilical cord after birth were tagged with enriched stable isotope 50Cr (96%, normal abundance 4.3%) and reinjected into the newborn. Blood samples (0.5 ml) were withdrawn at 30 min and thereafter at 6, 12, 24, 48, 72 and 120 hours old. Samples were centrifugalized and portion of RBC was then freeze-dried, weighed and sealed into polyethylene sheet bag together with 50Cr standard. Neutron irradiation was performed in the reactors of the JAERI with thermal neutron flux 5 X 10(13), 2 X 10(13), 8 X 10(13) cm-2s-1 at JRR-2, -3 and -4 respectively for 20 min and samples were left for about two weeks after irradiation. Induced radioactivity (51Cr, 59Fe) of the sample was measured with a Ge(Li) gamma-ray detector system and 4096 channels pulse height analyzer. Analysis of activity data was carried out by BOB-76 code. The RBC and total blood volume of the newborn was calculated using an isotopic dilution technique. We have investigated on tagging efficiency of 50Cr to RBC, washing effect and dilution rate by 50Cr content or 51Cr/59Fe ratio. Significant difference was observed in the total blood volume of newborns depending on the delivery style and in addition, it changed dynamically along the time elapsed after birth.     

Behaviors of sodium glycochenodeoxycholate and sodium glycoursodeoxycholate in binary mixed micelles of bile salt and nonionic surfactant

The behavior of sodium glycochenodeoxycholate (NaGCDC) and sodium glycoursodeoxycholate (NaGUDC) in binary mixed micelles consisting of bile salt and octaoxyethylene glycol mono n-decyl ether (C₁₀E₈) has been studied on the basis of micellar compositions, polarities of the interior of intramicelles, mean aggregation numbers and ¹H NMR measurements. Micellar compositions for both NaGCDC---C₁₀E₈ and NaGUDC---C₁₀E₈ systems showed a tendency to change from C₁₀E₈-rich micelles to bile-salt-rich micelles with an increase on the mole fraction of bile salts from the results of both theoretical calculations using the critical micelle concentration and the micellar polarity. The microenvironment of intramicelles for the NaGCDC---C₁₀E₈ system was found to be more hydrophobic than that for the NaGUDC---C₁₀E₈ system. Mean aggregation numbers of mixed micelles for both systems decreased abruptly with an increase in the mole fraction of bile salts in the range of low mole fraction, but those for NaGCDC were larger than those for NaGUDC. Furthermore, from the results of ¹H NMR measurements, the motions of the methyl group protons in the 18 position of the molecular structure of NaGCDC were slightly restricted with an increase in the mole fraction of NaGCDC. In contrast, the methyl group protons in the 18 and 19 positions of the molecular structure of NaGUDC became freer with an increase in the mole fraction of NaGUDC.