Red-light induced photoreaction of ozone-dimethylamine complex; matrix-isolation infrared spectra of dimethylamine-N-oxide and N,N-dimethylhydroxylamine

Photoreactions of Ozone–Tetrahydrothiophene, Ozone–Pyrrolidine, and Ozone–Thiazolidine Complexes Studied Using Matrix-Isolation IR and Visible Absorption Spectroscopies

“…No electronic transition bands corresponding to PyD, THT, and TAD appear in the visible-light region, and the absorption bands of the O 3 monomer were exceptionally weak to be detected using our apparatus. , However, clear and broad absorption bands were observed in the visible spectra of the O 3 -PyD, O 3 -THT, and O 3 -TAD complexes isolated in Ne matrices, as shown in Figure , which were similar to those previously reported; − the experimental spectra were separated into multi-Gaussian-type bands using the least-squares fitting method. The spectral shape of O 3 -PyD was separated into a strong band at 416 nm and a weak band at 552 nm, as shown in Figure a, and both bands decrease exhibiting similar behavior upon irradiation at λ ≥ 680 nm.…”

“…IR spectra were recorded on a Fourier transform infrared (FTIR) spectrophotometer (JEOL, SPX-200ST) at a spectral resolution of 0.5 cm –1 , whereas UV–visible spectra were recorded on a compact UV–visible spectrophotometer (StellerNet, Blue Wave) at a spectral resolution of 1.6 nm in the range of 300–800 nm for avoiding the effect of too intense absorption band of O 3 monomer. A xenon lamp (Asahi Spectra, Max-302 equipped with a visible-light module) was used as the visible-light source using short-wavelength cutoff filters (Asahi Spectra) to select the irradiation wavelength. , …”

“…Numerous studies on the UV-induced reactions of O 3 have been reported to date. , In contrast, the visible-light-induced reactions of O 3 that produce O­( 3 P) are not important in atmospheric chemistry because the cross sections of the Chappuis and Wulf bands appearing at ∼600 nm and in the near-infrared region are much lower than the Hartley band at ∼250 nm. , In addition, O­( 3 P) produced via visible photoreaction of O 3 has a negligible effect on the various reactions observed in the troposphere. However, it has often been reported that the visible-light absorption of O 3 is enhanced by forming a molecular complex isolated in a low-temperature noble-gas matrix. − For example, O 3 -ferrocene isolated in an Ar matrix exhibits two bands at 361 and 765 nm, whereas O 3 -dimethylsulfide (DMS) in a Ne matrix has two bands appearing at 480 and 600 nm, and two bands are observed for O 3 -dimethylamine (DMA) in an Ar matrix at 430 and 613 nm . In addition, the bands observed at 465 and 645 nm in the visible spectrum of O 3 -trimethylamine (TMA) in an Ar matrix are shifted to 455 and 635 nm, respectively in a Ne matrix .…”

“…More interestingly, visible-light irradiation corresponding to the electronic transition band induces O atom transfer from O 3 to the paired molecule in the low-temperature matrix. It is particularly common that the O atom combines with the lone pair of the paired molecule in the primary photoreaction process. − ,− For instance, O 3 -ClBr yields ClBrO upon laser irradiation at 870 nm, red-light photolysis of O 3 -PCl 3 and O 3 -PBr 3 yields OPCl 3 and OPBr 3 , respectively, and O 3 -C 2 H 5 I produces C 2 H 5 IO upon irradiation at λ > 800 nm . Although the electronic transition-enhanced mechanism and visible-light-induced photoreaction mechanism of O 3 -molecule complexes are interesting in molecular science, they have not yet been elucidated because the accurate theoretical analysis of O 3 and its complexes is still difficult, , while only a few experimental studies on their photoreactions have been published to date. − ,− …”

“…We have focused on the photoreactions and interaction of O 3 with S and N atoms in the paired molecules of these complexes, − in which the visible-light-induced photoreactions of O 3 -DMS, O 3 -DMA, and O 3 -TMA commonly yield their corresponding oxide compounds dimethylsulfoxide, dimethylamine- N -oxide, and trimethylamine- N -oxide during the primary process. In addition, it has been observed that the asymmetric stretching mode of O 3 is slightly red-shifted in the O 3 -DMS complex, whereas it is blue-shifted in O 3 -DMA and O 3 -TMA.…”