Gas-Phase Ion Chemistry of Oxalyl Chloride:  An Electron Bombardment Matrix Isolation FTIR Spectroscopic Study

Abstract

The gas-phase ion chemistry of oxalyl chloride has been studied by bombardment of dilute mixtures of oxalyl chloride in rare gases with fast electrons followed by isolation of the decomposition products in the diluent rare gases at 12 K. The major products observed in the matrix by FTIR absorption spectroscopy are phosgene, carbonyl chloride radical, and carbon monoxide. Some CCl was observed when the diluent gas was argon. No ions were identified in the matrix, and it is proposed that the initially isolated ions are neutralized by secondary electrons impinging on the positively biased matrix. A change in the relative intensities of products was observed when the diluent rare gas was changed from argon to krypton and when the mixture was doped with varying concentrations of CO or N2. These doping experiments give direct evidence for at least two mechanisms for formation of the carbonyl chloride cation, one of which involves secondary decomposition of phosgene radical cation. The products obtained here are compared with those obtained by EI mass spectrometry. It is suggested that the different product intensities observed in EI and CE mass spectra are due to the fact that product decomposition is efficiently quenched in the source following CE ionization.

The proton-bound rare gas compounds (RgHRg′)+ (Rg=Ar, Kr, Xe)—a computational approach

“…The values on the diagonal correspond to the experimental values in homogeneous matrices.6,7 All other values are from ref. 19. Clearly, the absorption bands shift according to the increasing polarizability of the environment.…”

Infrared spectra of homogeneous and heterogeneous proton-bound dimers in the gas phase

“…The mixed rare-gas proton-bound dimers, Ar-H 1 -Kr, Ar-H 1 -Xe and Kr-H 1 -Xe have also been characterized by infrared spectroscopy in rare gas matrices. 19 Vibrational spectra of trapped ions have been obtained using infrared photodissociation (IRPD) or infrared multiple photon dissociation (IRMPD) techniques using tuned infrared radiation from a CO 2 laser or Nd:YAG-pumped OPO laser 20,21 to irradiate mass-selected ions injected into an octopole ion guide. 22,23 When the infrared radiation is resonant with an internal mode of the stored ion, it is absorbed causing dissociation of the ion which is monitored by mass spectrometric means.…”

Heterocations in Superacid Systems

“…In the crystals of the dark green compound, weak multiple contacts exist between xenon and fluorine atoms. 1063,1065 Even methylated xenon and krypton, CH 3 Xe þ and CH 3 Kr þ , have been observed by Holtz and Beauchamp 1066 in the gas phase. 1051 Of the possible cationic species (Xe n mþ , n ¼ 2-4; m ¼ 1, 2), calculated vibrational spectra and energies agree well with those observed for Xe 4 þ , but the presence of higher xenon aggregates (Xe 4 þ ÁXe n ) cannot be ruled out.…”

“…1049 Drews and Seppelt 1050 were the first, however, to report the isolation and molecular structure of Xe 2 þ Sb 4 F 21 À (365) [Eq. 1062 The Xe 2 H þ cation has been observed in lowtemperature matrices, 1063 whereas Xe 2 H 3 þ has been studied by ab initio methods. In the crystals of the dark green compound, weak multiple contacts exist between xenon and fluorine atoms.…”