27 research outputs found
Dynamics of Intramolecular Hydrogen-Atom Migrations in 2-Hydroxy-3-nitropyridine Studied by Low-Temperature Matrix-Isolation Infrared Spectroscopy and Density Functional Theory Calculation
Intramolecular Hydrogen Atom Tunneling in 2-Chlorobenzoic Acid Studied by Low-Temperature Matrix-Isolation Infrared Spectroscopy
Methyl-Group Move in Low-Temperature Rare-Gas Matrixes and Conformational Analysis of 1,4-Dimethoxybenzene
Photoisomerization and Tunneling Isomerization of Tetrachlorohydroquinone in a Low-Temperature Argon Matrix
Visible light induced reactions of nitrogen dioxide with conjugated dienes in a low-temperature argon matrix
Infrared Spectra and Density Functional Theory Calculations of Iminoxy Radicals Produced by Visible-Light-Induced Reaction between 1-Phenyl-1-Propyne and NO 2
UV-Induced Photoisomerization of Acetylacetone and Identification of Less-Stable Isomers by Low-Temperature Matrix-Isolation Infrared Spectroscopy and Density Functional Theory Calculation
Hydrogen-Atom Tunneling of 2,5-Dichloro-3,6-dihydroxy-1,4-benzoquinone in a Low-Temperature Argon Matrix Studied by FTIR Spectroscopy
Reversible Photoisomerization among Triplet Amino Naphthylnitrene, Triplet Diimine Biradical, and Indazole: Matrix-Isolation IR Spectra of 8‑Amino-1-naphthylnitrene, 1,8-Naphthalenediimine, and 1,2-Dihydrobenz[<i>cd</i>]indazole
Reaction
mechanisms of nitrene, one of the most famous biradicals,
have been frequently studied, and many spectral data have been obtained
so far. In the present study, the experimental IR spectra of triplet
8-amino-1-naphthylnitrene (<sup>3</sup>ANN), a triplet diimine biradical
1,8-dihydro-1,8-naphthalenediimine (<sup>3</sup>DND), and 1,2-dihydrobenzÂ[<i>cd</i>]Âindazole (DBI), which are produced in the UV photolysis
of 1,8-diaminonaphthalene in an Ar matrix and identified by a combination
method of IR spectroscopy and DFT quantum chemical calculations, are
first reported. <sup>3</sup>ANN is found to change to DBI by hydrogen-atom
migration with bond making between the two nitrogen atoms upon visible-light
irradiation (λ > 580 nm) with its backward reaction caused
by
350 nm irradiation. In addition, <sup>3</sup>ANN isomerizes to <sup>3</sup>DND by 700 nm irradiation, while its backward reaction occurs
upon 500 nm irradiation. The wavelength dependences of these photoisomerizations
are explained in terms of their electronic transition energies estimated
by time-dependent DFT calculations. It is concluded that the novel
reversible photoisomerization system among <sup>3</sup>ANN, <sup>3</sup>DND, and DBI is totally different from the well-known photoisomerization
between phenylnitrene and a seven-membered cyclic compound
Infrared and Electronic Spectra of Radicals Produced from 2‑Naphthol and Carbazole by UV-Induced Hydrogen-Atom Eliminations
The photoreaction mechanisms of 2-naphthol and carbazole
in low-temperature
argon matrices have been investigated by infrared and electronic absorption
spectroscopy with aids of density-functional-theory (DFT) and time-dependent
DFT (TD-DFT) calculations. When the matrix samples were irradiated
upon UV light, 2-naphthoxyl and N-carbazolyl radicals were produced
by the elimination of the H atom in the O–H group of 2-naphthol
and in the N–H group of carbazole, respectively. The observed
IR and electronic absorption spectra of the radicals were reproduced
satisfactorily by the quantum chemical calculations. To understand
a role of the radicals in the excited-state proton transfer (ESPT),
the fluorescence and excitation spectra of 2-naphthol and carbazole
were measured in aqueous solution at room temperature as well as in
the low-temperature argon matrices. It was found that the intensity
of the fluorescence emitted from carbazole anion in aqueous solution
decreased when oxygen gas was blown into the solution