Condensations of brominated products of o-acetylbenzophenone with several primary amines

2-Bromo-3-phenylinden-1-one 2 reacted with phenylthiourea to produce 2-phenylimino-8-phenylindeno[1,2-d]thiazole (heteropentalene) 4 in moderate yield and bis-substituted-indenyl sulfide 5 in low yield. Whereas, from the reaction of 2 with thiourea or its methyl derivative only 5 was obtained in moderate yield. Another brominated compound, dibromoacetylbenzophenone and several primary amines afforded iminoindanone derivatives 6 .     

Resonance Raman scattering of excitonic polaritons by LO and acoustic phonons in ZnTe

We have observed dispersive two-phonon Raman scattering of polaritons by LO and acoustic phonons near the lowest exciton state of ZnTe. From the Stokes shifts of these Raman lines, it has been found that the scattering process switches from an acoustic phonon followed by one LO phonon to the reversed one: a LO phonon followed by an acoustic one.     

Stimulated emission effects in excitonic molecule luminescence of CuCl under resonant two-photon excitation

Luminescence spectra of excitonic molecules in CuCl resonantly created by nano-second dye laser excitation are measured at 4.2 K changing the lenghts of the excited region. The spectra are dominated by stimulated emission. The gain coefficient for the M_T line is saturated more easily than that for M_L, though the former is larger under unsaturated conditions. These gain characteristics explain well various stimulated emission effects observed.     

Polymerization of diallyl phthalate and gelation of poly(diallyl phthalate) by copolymerization with styrene

In the polymerization of diallyl phthalate in bulk at 60°C with azobisisobutyronitrile, extensive branching of the polymers obtained before gelation was ascertained from the enhanced broadening of the molecular weight distribution, coupled with the decrease of the residual unsaturation. Copolymerization of poly(diallyl phthalate) and styrene in bulk at 80°C with benzoyl peroxide was studied in detail with regard to the gel formation. The gel time increased with increasing fraction of styrene in feed. Both the gel yield and the conversion of styrene incorporated into the gel increased steadily with polymerization time, even after the total conversion of styrene exceeded 95%. The polystyrene recovered by saponification of the gel was found to carry hydroxyl groups, which should come from the copolymerized diallyl phthalate units. It was concluded that styrene behaved as a diluent in the early stage, and that the crosslinking after gelation of the system proceeded mainly through polymer–polymer reactions involving the occluded polystyryl radicals and poly(diallyl phthalate).     

Chiral recognition conducted by tartaric acid derivatives in nonaqueous media

Chiral recognition of hydroxycaboxylic acid, amino acid and 1,2-diol derivatives using diastereomeric complexation based on hydrogen bond with L(+)-N,N′-diisopropyl-tartramide (DIPTA) is described.     

Destructive interference during high harmonic generation in mixed gases

We report on the first experimental evidence of the destructive and constructive interference of high harmonics generated in a mixed gas of He and Ne, which facilitates the coherent control of high harmonic generation. Theoretically, we develop an analytical model of high harmonic generation in mixed gases and succeed in reproducing the experimental results and deriving the optimization conditions for the process. The observed interference modulation is attributed to the difference between the phases of the intrinsically chirped harmonic pulses from He and Ne, which leads to a novel method for broadband measurement of the harmonic phases and for observing the underlying attosecond electron dynamics.     

Ultrafast dynamics of photoactive yellow protein via the photoexcitation and emission processes

Pump-dump fluorescence spectroscopy was performed for photoactive yellow protein (PYP) at room temperature. The effect of the dump pulse on the population of the potential energy surface of the electronic excited state was examined as depletion in the stationary fluorescence intensity. The dynamic behavior of the population in the electronic excited state was successfully probed in the various combinations of the pump-dump delay, the dump-pulse wavelength, the dump-pulse energy and the observation wavelength. The experimental results were compared with the results obtained by the femtosecond time-resolved fluorescence spectroscopy.