Picosecond dynamics of excited singlet states in organic microcrystals: Diffuse reflectance laser photolysis study

Absorption spectra and picosecond dynamics of the singlet exciton states of benzil and p-terphenyl in a microcrystal have been measured for the first time by analyzing the diffuse reflected spectra of the picosecond continuum.     

An attempt to detect fracto-fusion during microwave irradiation of D2O loaded silica gel

Neutron emission has been examined in a system in which the recently reported phenomenon of fracto-fusion might be occurring. No positive evidence has been obtained for cold fusion. The upper limit of the fusion has been 0.0112 events/sec in each specimen containing 0.33 g D₂O.     

Time-resolved fluorescence of crown ether styrul dyes

Photophsical processes are studied in a new class of dyes contining a chromophoric part and a crown ether part. Fluorescence decays were oebserved to be strongly dependent on temperature in the range from 294 to 4 K. Photoinduced isomerization and electron transfer are considered as possible mechanisms to explain the results.     

Hydroxylation of phenolic compounds under the condition of ultrasound in aqueous solution

Ultrasound (200 kHz)-assisted hydroxylation of phenolic compounds, such as phenol, 4-methyl phenol, 4-hydroxyanisol, 2-naphthol, catechol, resorcinol, 3-t-butyl-4-hydroxyanisole, 3-methyl-4-hydroxyanisole, in aqueous solution was successfully carried out in 12–18 h to give the hydroxylated products which were identified as their respective acetates.     

SPECTROSCOPIC STUDIES ON THE STRUCTURES OF RETINOCHROME and METARETINOCHROME*

Abstract– Spectroscopic measurements of retinochrome and the related photoproduct, metaretino-chrome, were carried out to determine the conformation of the retinal and the protein. Absorption spectra with fourth derivatives indicate that the tryptophan residues are located in a hydrophobic core and that the environment around these residues does not change after light irradiation. Circular dichroism measurements indicate that retinochrome has a high helical content which is not altered by the conversion of retinochrome to metaretinochrome. Fourier transform infrared difference spectra demonstrate that retinochrome has the all-trans retinal and metaretinochrome has the 11-CM retinal. Retinochrome has an absorption due to amino acid residue(s) which changes in metaretinochrome. This work demonstrates that conformational changes are not induced during the conversion but the electrical charge(s) of the protein are changed by irradiation.     

Base hydrolysis of tris(acetylacetonato)metal(III) complexes involving technetium and ruthenium

Irradiation of chloro- and bromoalkanes in solid cis-decalin-d₁₈ results in the selective formation (as major paramagnetic species) of alkyl radicals that are specific or the haloalkane solute, in addition to matrix radicals. The method offers a convenient and universal technique for generating, specific alkyl radicals and for examining their powder ESR spectrum. Examples of the generation of chain-end, penultimate and interior alkyl radicals are given. Computer calculations, in which spectra of penultimate and interior radicals are added, clearly demonstrate that quite extensive amounts of interior radicals can be present in a radical mixture, without considerably affecting the composite spectrum.     

Formation of nitridotechnetium (VI) μ-oxo dimer complexes with EDTA and EDDA

Reactions of [⁹⁹TcNCl₄]^– with ethylenediaminetetraacetic acid (EDTA) and ethylenediamine-N, N-diacetic acid (EDDA) in a mixture of water and acetone gave Tc^VIN-EDTA and Tc^VIN-EDDA complexes. The infrared spectra of both reaction products showed the existence of the TcN and C=O groups. The elemental analysis indicated the 11 TcN-ligand ratio in the EDTA and EDDA complexes. Electrophoresis showed that the Tc^VI-EDTA complex was an anionic species in a perchlorate solution. For the Tc^VIN-EDDA complex, neutral and anionic species were formed, depending on the pH of the solution. Formation of the -oxo dimer complexes was suggested from the UV-Vis absorption spectra.