(μ‐2,11‐Dithia­[3.3]paracyclo­phane‐κ2S:S′)bis­[(6‐carboxy­pyridine‐2‐carboxylato‐κ2N,O6)silver(I)]: a mixed‐ligand silver‐based dinuclear compound

In the title complex, [Ag₂(C₇H₄NO₄)₂(C₁₆H₁₆S₂)], each Ag^I atom is trigonally coordinated by one S atom of a 2,11‐dithia­[3.3]paracyclo­phane (dtpcp) ligand, and by one N and one O atom of a 6‐carboxy­pyridine‐2‐carboxylate ligand. Dtpcp acts as a bidentate ligand, bridging two inversion‐related Ag^I atoms to give a dinuclear silver(I) compound. The dinuclear moieties are inter­connected via O—H·O hydrogen bonds to form a two‐dimensional zigzag sheet. Two such sheets are inter­woven viaπ–π inter­actions between pyridine rings, affording an inter­woven bilayer network.     

CALET Results after Three Years on Orbit on the International Space Station

Physics of Atomic Nuclei - The CALorimetric Electron Telescope (CALET) is an astroparticle physics experiment installed on the International Space Station since August 2015. The CALET mission was...     

A Mn12 single-molecule magnet [Mn12O12(OAc)12(dpp)4] (dppH = diphenyl phosphate) with no coordinating water molecules

The preparation and physical characterization are reported for a novel single-molecule magnet [Mn(12)O(12)(OAc)(12)(dpp)(4)] (dppH = diphenyl phosphate) with no coordinating water molecules. The crystal structure analysis reveals that there are four five-coordinate Mn(III) ions with Mn.H approaches. Addition of water in CD(2)Cl(2) solution was monitored by (1)H NMR, which showed that H(2)O could coordinate to a vacant site of a five-coordinate Mn(III) ion in solution. The measurements and analyses of magnetization hysteresis and ac magnetic susceptibility indicate that the title complex is a single-molecule magnet with a quantum tunneling behavior, whose ground state was tentatively assigned to S = 10 with g = 1.78 and D = -0.60 K.     

Exciton transitions from spin-orbit split off valence bands in layer compound InSe

The absorption spectrum of E′₁ and E₁ exciton transitions in 3R(γ)-InSe has been measured at 1.8 K. Their photon energies, oscillator strengths and polarization dependences are fully explained in terms of Hopfield's quasicubic model. The analysis shows that the valence band structure reflects the crystalline field anisotropy characteristics of its layer structure.     

Observation by an air-shower array in Tibet of the multi-TeV cosmic-ray anisotropy due to terrestrial orbital motion around the Sun

We report on the solar diurnal variation of the galactic cosmic-ray intensity observed by the Tibet III air shower array during the period from 1999 to 2003. In the higher-energy event samples (12 and 6.2 TeV), the variations are fairly consistent with the Compton-Getting anisotropy due to the terrestrial orbital motion around the Sun, while the variation in the lower-energy event sample (4.0 TeV) is inconsistent with this anisotropy. This suggests an additional anisotropy superposed at the multi-TeV energies, e.g., the solar modulation effect. This is the highest-precision measurement of the Compton-Getting anisotropy ever made.     

Domain population in SrTiO3 below the cubic-to-tetragonal phase transition

High-angle double-crystal X-ray diffractometry (HADOX) has been applied to measure the intensity around three reciprocal lattice points: 400, 040 and 004 of SrTiO₃. Each point splits into two in the tetragonal phase according to the appearance of three kinds of domains; the temperature dependence of the intensity of component peaks at these points was measured under identical conditions. The results show that the domain population varies with temperature in a range of about 20 K below the transition. It is found, however, that the total intensities of 400 and 004 of the tetragonal phase are constant; this is observed by summing up the relevant intensity at the three reciprocal lattice points.     

Total synthesis of spiruchostatin B aided by an automated synthesizer

The total synthesis of a natural product HDAC inhibitor, spiruchostatin B, was successfully achieved. A 5-step synthesis that included an asymmetric aldol reaction was carried out in an automated synthesizer to provide an (E)-(S)-3-hydroxy-7-thio-4-heptenoic acid segment that is the crucial structure of cysteine-containing, depsipeptidic natural products such as spiruchostatins, FK228, FR901375, and largazole for their inhibitory activity against HDACs.     

Synthesis and reaction of tricyclic tetrathiins and pentathiepins: novel formation of α-disulfines

Cyclic polysulfanes containing a norbornane skeleton (tetrathiins and pentathiepins) were synthesized by two methods. One is the sulfurization of camphor hydrazone with disulfur dichloride, and the other is the reaction of thiocamphor with disulfur dichloride. The reduction of tetrathiin with LiEt₃BH gave the corresponding dithiol that further reacted with methyl iodide to afford the corresponding methyl sulfide. Reaction of tetrathiin with (Ph₃P)₂PdCl₂ or NiBr₂ resulted in the formation of the corresponding dithiolene metal complexes. Tetrathiins were stereoselectively oxidized by m-CPBA to afford the corresponding α-disulfines.     

Coordination-insertion copolymerization of allyl monomers with ethylene

Coordination-insertion copolymerization of allyl monomers with ethylene was developed by using a palladium/phosphine-sulfonate catalyst. A variety of allyl monomers, including allyl acetate, allyl alcohol, protected allylamines, and allyl halides, were copolymerized with ethylene to form highly linear copolymers that possess in-chain -CH(2)CH(CH(2)FG)- units.