Exceptional Sequences over Path Algebras of Type A n and Non-Crossing Spanning Trees

Exceptional sequences are fundamental to investigate the derived categories of finite dimensional algebras. The aim of this note is to classify all the complete exceptional sequences over the path algebra of a Dynkin quiver of type A _n in terms of non-crossing spanning trees.     

Copper(I) complexes with fluorinated hydrotris(pyrazolyl)borate: Influence of electronic effects on their structure,physicochemical properties,and reactivity

Copper(I) coordination complexes of the anionic fluorinated ligand, hydrotris(3-trifluoromethyl-5-methyl-1-pyrazolyl)borate (L0f⁻), i.e. the copper(I) carbonyl complex, [Cu^I(L0f)(CO)] (1), the copper(I) triphenylphosphine complex, [Cu^I(L0f)(PPh₃)] (2), the copper(I) acetonitrile complex, [Cu^I(L0f)(NCMe)] (3), and the corresponding copper(I) triphenylphosphine complex with hydrotris(3,5-diisopropyl-1-pyrazolyl)-borate anion (L1⁻), i.e. [Cu^I(L1)(PPh₃)] (4), were synthesized in order to investigate the influence of the electron-withdrawing groups on the pyrazolyl rings. The structures of complexes 1, 2, and 4 were determined by X-ray crystallography. While X-ray crystallography did not show definitive trends in terms of copper(I) atom geometry, the clear influence of the electronic structure of the pyrazolyl rings is observed by spectroscopic techniques, namely, IR and multinuclear NMR spectroscopy. Finally, the relative stability of the copper(I) complexes is discussed.     

Reductive coupling reaction of aldehydes using indium(III) triflate as the catalyst

A reductive coupling reaction was effectively developed to convert an aldehyde to its symmetrical ether. The successful reactions required Et₃SiH and CH₂Cl₂ as the suitable solvent in the presence of a catalytic amount of In(OTf)₃. Various aldehydes were subjected to the method, and each afforded the expected ethers in good to excellent yields.     

2, 2'-bis(diphenylphosphino)-1, 1'-binaphthyl(binap) : A new atropisomeric bis(triaryl)phosphine. synthesis and its use in the rh(l)-catalyzed asymmetric hydrogenation of α-(acylamino)acrylic acids

Racemic 2, 2'-bis(diphenylphosphino)-l, 1'-binaphthyl has been synthesized from 2, 2'-dihydroxy-l, l'-binaphthyl in two steps and resolved into optically pure (R)-(+) and (S) (-) enantiomers by the use of (+)-di-μ-chlorobis[(S)-N,N-dimethyl-α-phenylethylamine-2C,N]dipalladium. This new axially dissymmetric bis(triaryl)phosphine serves as an excellent ligand for Rh(l)-catalyzed asymmetric hydrogenations of α-(acylamino) acrylic acids or esters. Factors controlling the enantioselectivity and mechanistic aspects are discussed on the basis of the ³¹P-NMR measurements     

Ligand Exchange Strategy for Tuning of Helicity Inversion Speeds of Dynamic Helical Tri(saloph) Metallocryptands

We developed a new strategy, ligand exchange strategy, for tuning the response speeds of helicity inversion of a metal-containing helical structure. This is based on the exchange of the two axial amine ligands of the octahedral Co³⁺ centers in the metallocryptands [LCo₃X₆] (X=axial amine ligand). The response speeds of the helicity induction were controlled by using different combinations of achiral and chiral amines as the starting and entering ligands, respectively. The response speeds of the helicity inversion from P to M were also tuned by using different combinations of chiral amines.     

Ballistic transport in InSb mesoscopic structures

Two different device geometries are fabricated to investigate ballistic transport of electrons in low-dimensional InSb structures. Negative bend resistance is observed in four-terminal devices of channel widths ranging from 0.2 to 0.65 μm. We also report the observation of conductance quantization in quantum point contacts fabricated using in-plane gates. The one-dimensional subbands depopulate with increasing transverse magnetic field up to 3 T. Zeeman splitting is resolved at magnetic fields above 0.9 T.     

Spectral statistics and the Dzyaloshinsky–Moriya interaction of nanomagnet

The spectral statistics of nanomagnet V₁₅ is studied. We study the dependence of the Dzyaloshinsky–Moriya interaction in V₁₅ on the spectral statistics.     

Design, synthesis, and properties of 2',4'-BNA(NC): a bridged nucleic acid analogue

The novel bridged nucleic-acid analogue 2',4'-BNA(NC) (2'-O,4'-C-aminomethylene bridged nucleic acid), containing a six-membered bridged structure with an N-O linkage, was designed and synthesized efficiently, demonstrating a one-pot intramolecular NC bond-forming key reaction to construct a perhydro-1,2-oxazine ring (11 and 12). Three monomers of 2',4'-BNA(NC) (2',4'-BNA(NC)[NH], [NMe], and [NBn]) were synthesized and incorporated into oligonucleotides, and their properties were investigated and compared with those of 2',4'-BNA (LNA)-modified oligonucleotides. Compared to 2',4'-BNA (LNA)-modified oligonucleotides, 2',4'-BNA(NC) congeners were found to possess: (i) equal or higher binding affinity against an RNA complement with excellent single-mismatch discriminating power, (ii) much better RNA selective binding, (iii) stronger and more sequence selective triplex-forming characters, and (iv) immensely higher nuclease resistance, even higher than the S(p)-phosphorthioate analogue. 2',4'-BNA(NC)-modified oligonucleotides with these excellent profiles show great promise for applications in antisense and antigene technologies.     

Evidence for in-medium modification of the phi meson at normal nuclear density

Invariant mass spectra of e(+) e(-) pairs have been measured in 12 GeV p + A reactions to detect possible in-medium modification of vector mesons. Copper and carbon targets are used to study the nuclear-size dependence of e(+) e(-) invariant mass distributions. A significant excess on the low-mass side of the phi meson peak is observed in the low betagamma(= beta/square root(1-beta(2))) region of phi mesons (betagamma < 1.25) with copper targets. However, in the high betagamma region (betagamma > 1.25), spectral shapes of phi mesons are well described by the Breit-Wigner shape when experimental effects are considered. Thus, in addition to our earlier publications on rho/omega modification, this study has experimentally verified vector meson mass modification at normal nuclear density.