New monoterpene glycoside esters and phenolic constituents of Paeoniae radix, and increase of water solubility of proanthocyanidins in the presence of paeoniflorin

Seven new monoterpene glycoside esters related to paeoniflorin were isolated from Paeoniae Radix, together with polymeric proanthocyanidins, polygalloylglucoses and 48 known compounds (a benzoylsucrose, seven aromatic acids, adenosine, nine monoterpene glycosides, eight flavan-3-ols, a catechin dimer formed by oxidation, seven proanthocyanidins, three galloylsucroses, five galloylglucoses, and six ellagitannins). The structures of the new compounds were determined by spectral investigation including two-dimensional NMR techniques. In addition, increased water solubility of polymeric proanthocyanidin in the presence of paeoniflorin was examined by n-octanol-water partition and 1H-NMR spectral experiments.     

Effect of fluctuations on tunneling currents via fine tin particles

Tunnel junctions containing Sn particles inside the oxide barrier have been prepared. Tunneling currents via these particles are measured. Interpretation is given in terms of the effect of fluctuations on the tunneling density of states in a “zero-dimensional” superconductor.     

High-resolution infrared spectrum of chlorine dioxide: The ν1 fundamental band

The B-type ν₁ fundamental band of chlorine dioxide has been observed with the resolution of 0.06 cm^?1, and several molecular parameters have been derived for the ³⁵ClO₂ isotopic species. The spectrum has been partially resolved by a tunable diode laser, and many doublet structures have been observed providing sufficient data to determine the spin-rotation interaction constants.     

The nature of the vibronic coupling in a metalloporphyrin and its Raman scattering

It has been shown that a Raman line of a nontotally symmetric vibration (b_1g, b_2g, or a_2g) of a metalloporphyrin (D_4h) can be caused, not only by a vibronic coupling between the first ($\text{A}\text{?}$) and second ($\text{B}\text{?}$) excited electronic states but also by a vibronic coupling within one of the electronic states (let us call the former the QS mechanism and the latter the QQ and/or SS mechanism). A simple formulation has been made for each of those different mechanisms, so that a numerical calculation can be made of the excitation profile of a Raman scattering for a given set of coupling constants and damping factors. Next, the result of an examination is given of the excitation profile of the Raman scatterings of some of the b_1g, b_2g, and a_2g vibrations of nickel octaethylporphyrin and nickel octaethyltetrachloroporphryin. Most of the Raman lines of these nontotally symmetric vibrations show a resonance effect only in the Q-band ($\text{A}\text{?}\text{←}\text{X}\text{?}$) region but not in the Soret-band ($\text{B}\text{?}\text{←}\text{X}\text{?}$) region. On the basis of this fact, it has been suggested that those Raman lines are caused mainly by the QQ mechanism rather than the QS mechanism. The observed vibrational structure of an excitation profile also seems to support this suggestion.     

Numerical simulation of H2/air detonation using unstructured mesh

To explore the capability of unstructured mesh to simulate detonation wave propagation phenomena, numerical simulation of H₂/air detonation using unstructured mesh was conducted. The unstructured mesh has several adv- antages such as easy mesh adaptation and flexibility to the complicated configurations. To examine the resolution dependency of the unstructured mesh, several simulations varying the mesh size were conducted and compared with a computed result using a structured mesh. The results show that the unstructured mesh solution captures the detailed structure of detonation wave, as well as the structured mesh solution. To capture the detailed detonation cell structure, the unstructured mesh simulations required at least twice, ideally 5times the resolution of structured mesh solution.      

Application of Infrared Spectroscopy to Structure Studies of Nucleic Acids

Abstract

The purpose of this review is to show the extent to which infrared spectroscopy has been and will be useful for elucidating the molecular structures of nucleic acids.     

The Allylic Rearrangement. V.1 Reaction of 4-Haloisophorone with Sodium Methoxide in Methanol

Treatment of 4-bromoisophorone with sodium methoxide gave 2-methoxyisophorone (4). Reaction of 4-chloroisophorone with sodium methoxide at 65–70° C afforded Favorskii-type rearangement product along with 4.