Visible-light-Induced Reaction of an Ozone–Trimethylamine Complex Studied by Matrix-Isolation IR and Visible Absorption Spectroscopies

Abstract

A visible-light-induced reaction of an O 3 −trimethylamine (TMA) complex isolated in low-temperature noble-gas matrices is investigated by infrared (IR) and visible absorption spectroscopies using the DFT calculation. The complex isolated in a Ne matrix yields trimethylamine-N-oxide (TMAO) upon irradiation (λ ≥ 800 nm) by dissociation of O 3 . When the wavelength of radiation is changed to λ = 455 nm, two stable conformers of dimethylaminomethanol (DMAM) are recognized besides TMAO. In an Ar matrix, DMAM and not TMAO is mainly produced upon λ = 455 nm irradiation. The photoreaction mechanism of the O 3 − TMA complex with a single collision reaction between O( 3 P) and TMA in the gas phase to produce OH and CH 2 N(CH 3 ) 2 radicals is discussed.

Observation of Light-Induced Reactions of Olefin–Ozone Complexes in Cryogenic Matrices Using Fourier-Transform Infrared Spectroscopy

“…In this study, the types of photoproducts derived were not dependent on the wavelength of the light source. Kamata et al [53] and Kon et al [54] reported the switching of photoreaction channels at visible wavelengths. It is still not clear how and why such differences arise, which presents another issue to be solved.…”

“…length of the light source. Kamata et al [53] and Kon et al [54] report photoreaction channels at visible wavelengths. It is still not clear how ferences arise, which presents another issue to be solved.…”

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

“…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 .…”

“…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 . These studies suggest that the absorption wavelengths of O 3 are affected by the type of paired molecule and the surrounding medium.…”

“…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. − ,− …”