Synthesis and properties of a dithiirane trans-1,2-dioxide, a three-membered vic-disulfoxide

cis- and trans-3-(1-adamantyl)-3-tert-butyldithiirane 1-oxides were oxidized with dimethyldioxirane to give the trans-1,2-dioxide. Thermal decomposition of the 1,2-dioxide yielded the corresponding (E)- and (Z)-sulfines, thioketone, and cis- and trans-dithiirane 1-oxides. In the thermolysis, decomposition to the sulfines and SO was the main path and that to the thioketone and SO(2) was the minor one. The two decomposition processes and epimerization to the cis-1,2-dioxide were analyzed theoretically. SO generated in situ reacted with thioketones as additives to give the corresponding dithiirane 1-oxides.     

Stable operation of a 300-m laser interferometer with sufficient sensitivity to detect gravitational-wave events within our galaxy

TAMA300, an interferometric gravitational-wave detector with 300-m baseline length, has been developed and operated with sufficient sensitivity to detect gravitational-wave events within our galaxy and sufficient stability for observations; the interferometer was operated for over 10 hours stably and continuously. With a strain-equivalent noise level of h approximately 5x10(-21)/sqrt[Hz], a signal-to-noise ratio of 30 is expected for gravitational waves generated by a coalescence of 1.4M-1.4M binary neutron stars at 10 kpc distance. We evaluated the stability of the detector sensitivity with a 2-week data-taking run, collecting 160 hours of data to be analyzed in the search for gravitational waves.     

Time-reversal symmetry-breaking superconductivity in heavy-fermion PrOs4Sb12 detected by muon-spin relaxation

We report on muon-spin relaxation measurements of the 4f(2)-based heavy-fermion superconductor filled-skutterudite Pr(Os4Sb12. The results reveal the spontaneous appearance of static internal magnetic fields below the superconducting transition temperature, providing unambiguous evidence for the breaking of time-reversal symmetry in the superconducting state. A discussion is made on which of the spin or orbital component of Cooper pairs carries a nonzero momentum.     

Structure and Metabolic‐Flow Analysis of Molecular Complexity in a 13C‐Labeled Tree by 2D and 3D NMR

Improved signal identification for biological small molecules (BSMs) in a mixture was demonstrated by using multidimensional NMR on samples from ¹³C‐enriched Rhododendron japonicum (59.5 atom%) cultivated in air containing ¹³C‐labeled carbon dioxide for 14 weeks. The resonance assignment of 386 carbon atoms and 380 hydrogen atoms in the mixture was achieved. 42 BSMs, including eight that were unlisted in the spectral databases, were identified. Comparisons between the experimental values and the ¹³C chemical shift values calculated by density functional theory supported the identifications of unlisted BSMs. Tracing the ¹³C/¹²C ratio by multidimensional NMR spectra revealed faster and slower turnover ratios of BSMs involved in central metabolism and those categorized as secondary metabolites, respectively. The identification of BSMs and subsequent flow analysis provided insight into the metabolic systems of the plant.     

Convenient synthesis of (+)-valiolamine and (-)-1-epi-valiolamine from (-)-vibo-quercitol

Convenient and practical synthesis of (+)-valiolamine and (-)-1-epi-valiolamine from (-)-vibo-quercitol, 1-deoxy-L-myo-inositol, readily obtained by bioconversion of myo-inositol, is described.     

An alternative synthetic route of [3(5)](1,2,3,4,5)cyclophane,and structural properties of multibridged [3(n)]cyclophanes and their charge-transfer complexes in the solid state

To develop an improved synthetic route to [3(6)](1,2,3,4,5,6)cyclophane (CP) 2, a more practical synthetic route to [3(5)](1,2,3,4,5)CP 3 than the original one was developed, which started from [3(2)](1,3)CP 7 via [3(4)](1,2,4,5)CP 5. The fundamental structural parameters of [3(n)]CPs (n = 3-6) in the solid state were elucidated, and the observed structures were in good agreement with the most stable conformers in solution and those predicted by the theoretical calculations. In the case of [3(6)]CP 2, the most stable C(6)(h) structure was observed in the crystal structure of the 2-TCNQ-F(4) (1:1) complex, whereas the highly strained structure with a D(6)(h) symmetry was observed in the crystal structure of 2 and the 2:TCNQ:benzene (1:1:1) complex because of a severe disorder problem. [3(n)]CPs (n > 3) showed reversible redox processes, and 2 (+0.39 V vs F(c)/F(c)(+), Cl(2)CHCHCl(2)) showed the lowest first half-wave oxidation potential [E(1/2) (I)] in [3(n)]CPs. The E(1/2) (I) data support the strong donating ability of 2 and its lower homologues. This is attributed to their molecular structures where effective hyperconjugation between the benzyl hydrogens and benzene ring is possible. By taking advantage of the strong electron-donating ability of [3(n)]CPs, their CT complexes with TCNE, TCNQ, and TCNQ-F(4) were prepared, and their crystal structural properties were examined. The single-crystal conductivity data of the CT complexes indicated that the TCNQ-F(4) complexes showed higher conductivities than the corresponding TCNQ complexes mainly due to a larger charge separation. Among the [3(n)]CP-TCNQ complexes, the [3(3)](1,3,5)CP 6-TCNQ-F(4) (1:1) complex showed the highest conductivity (10(-)(4) S cm(-)(1)), and this was ascribed to the formation of an infinite column of partially overlapped acceptors with a short acceptor-acceptor distance, while the formation of such a column was not observed in the 2-TCNQ-F(4) complex. Although the conductivities of the cyclophane-CT complexes are much lower than those of the TTF related complexes, this study successfully provides the basic knowledge for understanding the CT interactions in the solid state.     

Structural and physical properties of a novel TeO2-BaO-SrO-Ta2O5 glass system for photonic device applications

A detailed study on a novel TeO₂-BaO-SrO-Ta₂O₅ glass system developed for photonic device applications is reported in this paper. The glass transition and crystallization temperatures could be selected by varying the Ta₂O₅ content in this glass system. This glass system is found to have good thermal stability among tellurite glasses. Raman spectroscopy has been used as a tool to analyze the structural details of this technologically important glass system. In addition to the TeO₄ trigonal bipyramid and TeO₃ trigonal pyramid structural units, glasses in this system revealed the presence of an additional Raman band attributed to TaO₆ octahedra. The Raman bandwidth of the present glasses are broader compared to the conventional tellurite glasses by 35%. The influence of a gradual addition of the modifier oxides on the coordination geometry of tellurium atoms has been elucidated. Unlike the other tellurite glasses, even at higher modifier concentrations the TeO₄ structural units dominate in the glass network compared to TeO₃ trigonal pyramids. The ratio of TeO₄/TeO₃ structural units was discussed for different series of glass compositions.     

Synthesis of (+/-)-trans- or cis-(5-aminomethyltetrahydrofuranyl)imidazole by Mitsunobu cyclization: synthetic studies toward novel histamine H3 or H4-ligands

The (+/-)-trans- or cis-4(5)-(5-aminomethyltetrahydrofuranyl)imidazole [1 and 2] were synthesized by the Mitsunobu cyclization, starting from L-glutamic acid.     

Determination of low-pressure crystalline--liquid phase boundary of SnI(4)

The location of the liquidus in the low-pressure crystalline phase of SnI(4) was determined utilizing in situ x-ray diffraction measurements under pressures up to approximately 3.5 GPa. The liquidus is not well fitted to a monotonically increasing curve such as Simon's equation, but breaks near 1.5 GPa and then becomes almost flat. The results are compared to those from molecular dynamics simulations. Ways to improve the model potential adopted in the simulations are discussed.