Photo-oxidation of Iodomethane in Solid Argon

Abstract

Photolysis of iodomethane in the presence of oxygen in solid argon near 10 K has yielded several products detected by their vibrational absorption spectra. Isotopic labeling of reactants has proved methanal, water, hydrogen iodide, carbon monoxide, carbon dioxide, and hydro-peroxyl radicals to be significant products, and a further set of major absorptions is attributed to hydrogen hypoiodite HOI, hydrogen-bonded to methanal. Other minor vibrational features are discussed, and a possible reaction scheme is briefly outlined.

Matrix Isolation Study of the Photochemically Induced Reaction between Iodoethane and Ozone Trapped in Solid Argon at 16 K. Infrared Spectra of Iodosoethane (C2H5IO), Iodylethane (C2H5IO2), Ethyl Hypoiodide (C2H5OI), Hydrogen Hypoiodide (HOI), Hydrogen Iodide, and Ethanal Complexes

“…The band at 3474.1 cm -1 exhibited a large d-shift to 2565.2 cm -1 (ν H / ν D = 1.354) and a small 18 O-shift of 10.6 cm -1 and has been assigned to an O−H stretching vibration. The 579.8-cm -1 band exhibited a small d-shift of 5 cm -1 and 18 O-shift of 28.2 cm -1 , (the predicted 18 O-shift for the O−I diatomic is 29 cm -1 ) and, due to its similarities to bands observed for HOI, , has been assigned to an O−I stretch. In mixed ozone ( 16 O 3 - x 18 O x ) experiments the bands all appeared as doublets corresponding to the monoisotopic species, and hence only one oxygen atom is involved in each of these vibrational modes.…”

“…The photochemistry of the iodoethane−ozone complex is similar to that reported for the iodomethane−ozone complex, except for the observation in this study of hydrogen hypoiodide. However, the latter has been observed previously as a product in matrix experiments between iodomethane and molecular oxygen. , …”

“…However, the latter has been observed previously as a product in matrix experiments between iodomethane and molecular oxygen. 13,14 …”

Photochemical Reaction of Ozone with 2-Iodopropane and the Four Polyfluoroiodoethanes C2F5I, CF3CH2I, CF2HCF2I, and CF3CFHI in Solid Argon at 14 K. FTIR Spectra of the Iodoso-Intermediates (Z−IO), the Iodyl-Intermediates (Z−IO2), and the Various Complexes (CH3)2CO···HI, CF3C(O)H···XI, CF2HC(O)F···IF, and CF3C(O)F···XI (Where X = H or F)

“…However, given the species reported previously 4 and for the other precursors in this work, it seems likely that 2-hypoiodopropane might be present. This observation might also account for the disparity whereby HOI was detected in the matrix reactions of iodomethane 25,26 and molecular oxygen (during which long periods of ultraviolet photolysis were required) but not in the matrix 2 and gas-phase 19 experiments using ozone to produce oxygen atoms. The ν OI bands of HOI and C 2 F 5 OI are separated by ∼ 9 cm -1 , and thus it seems possible that the bands detected in this experiment could be attributed to ν OI of the fluoro-analogues, CF 3 CF 2 OI and FOI.…”

Full-dimensional analytical ab initio potential energy surface of the ground state of HOI

“…tance of a water molecule through CCSD(T)//B3LYP calculations [CCSD(T): coupled-cluster with single double and perturbative triple excitations]; and an extensive investigation of the kinetics of several iodine compounds was conducted by Canneaux et al 10 Experimentally, since the first spectroscopic studies by Ogilvie et al, 11 several investigations on the rovibrational spectra of hypoiodous acid were carried out, [12][13][14] as well as an observation of the pure rotational spectrum of HOI. 15 Of these works, it is relevant to emphasize the high resolution study of the OH stretch of HOI done by Klaassen et al, 14 which resulted in an estimate of geometrical and vibrational parameters, and the accurate geometry and harmonic force field determination conducted by Ozeki and Saito.…”