Long-range migration of a water molecule to catalyze a tautomerization in photoionization of the hydrated formamide cluster

The dynamics on the vacuum-ultraviolet one-photon ionization of a formamide-water cluster is investigated by a combination of theoretical reaction-path search and infrared spectroscopic methods. A keto-enol tautomerization of the formamide moiety occurs after photoionization by a catalytic action of the water molecule accompanied with its long-distance migration; the water molecule in the cluster migrates almost one turn around the formamide moiety. During the migration, the water molecule abstracts the proton of CH in the formamide moiety and carries it to the O atom side in the carbonyl group through a "catch and release"-type catalytic action.     

Is the neutral Knoevenagel reaction initiated by the carbanion formation?

The title reactions were studied by means of the density functional theory calculations. A base promoted reaction (called here ‘B’) was traced in a model composed of benzaldehyde, malononitrile, and (H₂O)₁₁. A neutral model (‘N’) of Ph‐CHO, H₂C(CN)₂ and (H₂O)₁₂ was also examined in line with a reported clean reaction. It was found that the ion pair of HC(CN) and H₃O⁺ is generated at the first step for N. For B, there are five elementary processes, and for N, four ones were obtained. By RB3LY/6‐311 + G** SCRF = PCM//RB3LYP/6‐31(+)G* energy calculations, the rate determining steps for both B and N reactions are the second proton removal, TS5(B) and TS3(N), respectively. In both B and N, the neutral species Ph(HO)HC‐CH(CN)₂ is the key intermediate. Copyright © 2010 John Wiley & Sons, Ltd.     

Self-Pumped Phase Conjugation in a Ce:BaTiO3 Crystal Pumped with Femtosecond Laser Pulses at 1053 nm Wavelength

Self-pumped phase conjugation in a cerium-doped barium titanate crystal pumped with femtosecond laser pulses at a 1053 nm wavelength was experimentally studied. A reflectivity of a self-pumped phase conjugation as high as 15#x0025; was demonstrated.     

Heterogeneous polycondensation for composition control of poly(p‐mercaptobenzoyl‐co‐p‐benzamide) by shearing

Composition control of aromatic poly(thioester‐amide) was examined by the reaction‐induced phase separation during polymerization of S‐acetyl‐4‐mercaptobenzoic acid (AMBA) and p‐acetylaminobenzoic acid (AABA) in aromatic solvent. The poly(thioester‐amide)s were obtained as precipitates and their yields became lower at the middle range of the content of AMBA in feed (χ_f). The contents of p‐mercaptobenzoyl (MB) moiety (χ_p) in the precipitates prepared without shearing were in good agreement with the χ_f values. In contrast to this, the χ_p values of the precipitates prepared at χ_f of 50–70 mol % under shearing were much lower than the χ_f values. The reaction rate of AMBA increased with shearing, whereas that of AABA was unchanged by shearing. This shearing effect on the reaction rates accelerated to form the homo‐oligomers. The solubility of MB oligomers enhanced by shearing, whereas that of p‐benzamide oligomers did not enhance owing to the strong interaction through hydrogen bonding. The MB oligomers were inhibited to be precipitated, resulting in the lower χ_p values than the χ_f values. The composition could be controlled by the application of the shearing to the heterogeneous polymerization. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4301–4308     

Triggered single-photon emission and cross-correlation properties in InAlAs quantum dot

Triggered single-photon generation from InAlAs quantum dot (QD) was demonstrated for the first time. Emitted photon energy coincides with high detection efficiency range of Si single-photon detectors, which is highly suitable for free-space communication. Single-QD spectroscopy and crossed photon correlation measurements unambiguously revealed that several emitting lines observed in a single mesa structure originated from the identical QD, and two temporary competing decay processes associated with neutral states and charged states were identified. Presence of the competing process is also inferred from an analysis of steady-state photoluminescence intensities. Formation process of charged exciton in QD is also discussed.     

Phase Distribution Measurement of Light Wave by Adaptive Control of Pupil Function with Local Algorithm

In developing a new method to measure the phase distribution of a light wave utilizing the adaptive control of the pupil function with a liquid crystal panel, the optimization procedure for the adaptive control is shown to improve when a local algorithm is adopted. The feasibility of the proposed system is confirmed by computer simulation as well as by some basic experiments.     

Mesogenicity of testosterone and estrone derivatives

Mesogenicity of 3β, 17β-bis(4-n-alkoxybenzoyloxy) androstene homologues (BABA) (carbon No. of alkoxy group, n, = 1-10) were studied by use of D.S.C. and a polarized microscopy. It was found that the n = 4-10 compounds of BABA have one cholesteric mesophase with high thermal stability enantiotropically, and that the n = 1-3 compounds decompose just above the melting point. Mesogenicities of BABA and several testosterone and estrone derivatives were also discussed from the perspective of chemical structure and shape. The presence of an intramolecular long-range dipole coupling in two alkoxybenzoyloxy chromophores is found in BABA from CD spectral studies.