Structures of two oxidation products obtained from palytoxin

The structures of two oxidation products of N-(p-bromobenzoyl)palytoxin were unambiguously determined by means of X-ray crystallographic analysis.     

Palladium-catalyzed decarboxylation-carbonylation of allylic carbonates to give β,γ-unsaturated esters under mild conditions

Allylic carbonates undergo facile palladium-catalyzed decarboxylation-carbonylation under mild conditions to give β,γ-unsaturated esters in high yields using palladium-phosphine complex as a catalyst.     

Structural studies on palytoxin,a potent coelenterate toxin

The structural elucidation of palytoxin is reported.     

ESR study on photoreaction of formato complex of europium(III) in HCOOH-HCOONa buffer solution

Matrix isolation ESR study showed that the ligated HCCO^? ion was decomposed into H⁺ and ·COO^? radical anion through CTTM process at λ = 254 nm, by contrast, ·CH₃ radical and CO₂ were produced from CH₃COO^? ligand. In order to explain the photo- and related reactions in the liquid solution, a proposal is made for a cyclic scheme conjugated with the photo-decomposition of the complex. The cycle consists of three steps; photo-reduction of H⁺ by Eu²⁺, radical alternation from ·H to ·COO^?, and oxidation of ·COO^? by Eu³⁺.     

Hydrodynamics in theO 4 gravity

We develop hydrodynamics in a new geometrical gravitational theory, calledO ₄ gravity, which we recently proposed. According to this formulation, matter is not necessarily conserved. The nonconservation of matter might have been considerable in an early era of cosmological evolution.     

Luminescence properties of Eu ion-exchanged Y-type zeolite

The luminescent properties of Eu ion incorporated in a Y-type zeolite have been studied. The emission spectrum at room temperature is due to the transition between ⁵D and ⁷F levels of the Eu³⁺ ion. However the emission band for Eu³⁺ decreased as this compound was degassed at above 300°C and the band emission, peaked at 445 nm, appeared. This band emission is associated with Eu²⁺ 5d to 4f transition.     

How can we properly define the Q2 dependent parton distribution function in QCD?

We discuss how we can properly define the Q² dependent parton distribution functions in quantum chromodynamics within the framework of the operator product expansion and renormalization group techniques. It is proposed that the moments of the parton distribution functions at Q² should be defined as the hadronic expectation values of the twist-2 operators renormalized at Q². The integro-differential equations for the parton densities obtained by Altarelli and Parisi are reproduced in the leading logarithmic approximation. An application of our present formalism will be given in the case of a longitudinal structure function.     

Long-term passive stabilization of the carrier-envelope phase of an intense infrared few-cycle pulse source

We present long-term stability of the carrier-envelope phase of intense infrared few-cycle pulses at 1.6 μm, generated by optical parametric chirped-pulse amplification. The employed system is based on a passive stabilization scheme that obviates the need for active feedback loops, and requires only control of environmental parameters. The stabilization is demonstrated to last for up to 45 h, during which the carrier-envelope phase drift is measured to be less than \(250\,\text{mrad}\) . This marks, to the best of our knowledge, the longest demonstrated phase-stable operation of a passively stabilized, amplified few-cycle source to date.     

An intramolecular charge/electron transfer chemiluminescence mechanism of oxidophenyl-substituted 1,2-dioxetane

The chemiluminescence (CL) mechanism of oxidophenyl-substituted 1,2-dioxetane was investigated by performing TD-DFT calculations on biradicals of three model compounds. We propose a novel mechanism of CL in which excitation of a dissociative intermediate by infrared radiation (IRE) of the surrounding solvent is considered. The excitation energies and oscillator strengths (f-values) were estimated for intermediates along the reaction coordinate (Rx). The difference in efficiencies of CL between syn- and anti-isomers of m-oxidophenyl-dioxetane is explained using the difference in potential curves of the singlet excited states (S) and the IRE mechanism. At the point where the biradical of the anti-isomer decomposes into two fragments, the interaction between the S and triplet (T) states is induced by a significant back electron transfer (BET) from the dioxetane group to the oxido-phenyl group and the S(1) excited state is stabilized and CL efficiency is enhanced. In the syn-isomer, the barrier in the S(1) potential curve to reach the final CL state is higher than for the anti-isomer, which reduces the efficiency. The poor CL yield for the p-isomer is ascribed to a much higher barrier in the potential curve of the S(1) state.