Core-modified phthalocyanine analogues with a seven-membered ring unit in place of a five-membered ring unit

A variety of phthalocyanine analogues with a seven-membered ring unit in place of a five-membered ring unit were synthesized from aromatic dicarbonitriles bearing cyano groups at 1,4-separate positions. Based on the spectroscopic analyses and theoretical calculations, tetraazachlorine-like electronic structures of these novel compounds stemming from severe twist of the conjugation system at the seven-membered ring unit have been revealed.     

Correlations betweenT c andn s/m * (carrier density/ effective mass) in high-T c and organic superconductors

We update our muon spin relaxation studies of the magnetic field penetration depth which show the correlations betweenT _c and the relaxation rate σ αn _s/m ^* (carrier density/effective mass) of hole-doped high-T _c cuprate superconductors (La₂, Sr₃)CuO₄, YBa₂Cu₃O₇ (Y_1−xPr_x)Ba₂Cu₃O₇, and other double and triple layer systems. These studies are extended to the organic superconductor (BEDT-TTF)₂Cu(NCS)₂.     

μ+SR study of two-dimensional antiferromagnets,delafossite-type compounds

⁺SR experiments were performed on delafossite-type compounds, CuCrO₂, AgCrO₂, CuFeO₂, which are model compounds of triangular lattice antiferromagnets. The initial asymmetries are much smaller than the expected value, implying muonium formation. The time spectra are composed of slow andfast relaxation components. We attributed the components to signals from ⁺ stopped at the center of O^2– ions andmuonium far from nuclear dipole moments, respectively. The asymmetries decrease belowT _N but no precession spectra were observed. Relaxation rates of slow andfast relaxation components show maxima atT _N.     

μ+SR in amorphous spin glasses Pd75Fe5Si20 and Pd75Fe5P20

The zero-field muon spin relaxation functionG _zz (t) has been measured as a function of reduced temperaturet=T/T _g in the amorphous metallic spin glasses Pd₇₅Fe₅Si₂₀ and Pd₇₅Fe₅P₂₀. The results are in qualitative agreement with earlier measurements on dilute alloy spin glasses, including an onset of static order belowT _g and a [t/(t-1)]² dependence of the correlation time τ_c aboveT _g. Both samples have the same τ_c (t) aboveT _g and almost identical static width Δ_S→Δ_o?43 μS^?1) asT»0, but thet-dependence of Δ_s nearT _g differs markedly.     

Perylene-tetrapalladium sandwich complexes

Bis-perylene-tetrapalladium sandwich complexes are synthesized and structurally characterized. These are the first examples of bis-arene sandwich complexes having metal-metal bond chains. X-ray crystallographic analyses showed that the tetrapalladium chain is bound to perylene ligands at the C8 edge position.     

Iridium-catalyzed ring cleavage reaction of cyclobutanone O-benzoyloximes providing nitriles

[reaction: see text] Iridium-catalyzed ring cleavage reaction of cyclobutanone O-benzoyloximes in the presence of 9,10-dihydroanthracene and potassium carbonate proceeds to give saturated nitriles via C-C bond fission at the sterically more hindered site.