Infrared matrix isolation study of the oxidation of H₂S by CrCl₂O₂

Abstract

The thermal and photochemical reactions between CrO2Cl2 and H2S have been investigated using matrix isolation infrared spectroscopy. Twin-jet co-deposition of the two reagents into argon matrices at 14 K followed by irradiation with light of lambda > 300 nm led to the growth of a number of new bands. These have been assigned to the HSOH-CrCl2O complex, and to SO2. These assignments were supported by deuterium isotopic substitution and high level density functional calculations. Merged-jet deposition with the reaction zone at temperatures above 125 degrees C led to substantial yields of SO2 and HCl, as well as the complex of HCl with excess parent H2S. The evidence suggests that the thermal and photochemical reactions may follow different pathways.

Matrix Isolation and Theoretical Study of the Reaction of Substituted Phosphines with CrCl2O2

“…Given the experimental differences, the agreement for all of these systems is excellent, and the products of the merged-jet co-deposition for each system are identified as the substituted phosphine oxide , formed through gas-phase oxygen atom transfer from CrCl 2 O 2 to the phosphine. Oxygen atom transfer in merged jet deposition has been observed previously for the CrCl 2 O 2 + (CH 3 ) 2 SO and H 2 S systems. , These results are also consistent with the calculated Δ E 0 ° and Δ G 298 ° values shown in Table , where these values ranged from essentially thermoneutral for the PCl 3 reaction to −37 kcal/mol for the PBr 3 reaction. The observation of the uncomplexed phosphine oxide upon initial deposition in the twin-jet experiments demonstrates that the oxygen transfer reaction is very rapid and occurs with a low activation barrier.…”

“…Oxygen atom transfer in merged jet deposition has been observed previously for the CrCl 2 O 2 + (CH 3 ) 2 SO and H 2 S systems. 24,41 These results are also consistent with the calculated ∆E 0 °and ∆G 298 °values shown in Table 6, where these values ranged from essentially thermoneutral for the PCl 3 reaction to -37 kcal/mol for the PBr 3 reaction. The observation of the uncomplexed phosphine oxide upon initial deposition in the twin-jet experiments demonstrates that the oxygen transfer reaction is very rapid and occurs with a low activation barrier.…”

Synthesis, Properties, and Structures of Chromium(VI) and Chromium(V) Complexes with Heterocyclic Nitrogen Ligands

“…[1][2][3][4][5] In a series of studies Ault and co-workers explored the reactions of CrO 2 Cl 2 with a variety of organic molecules and donor ligands at very low temperatures using matrix isolation IR spectroscopic techniques. [6][7][8][9][10][11] More conventional coordination studies are limited and the reports contradictory. The reactions of CrO 2 Cl 2 or of CrO 3 /HCl with Ndonor ligands (amines or nitrogen heterocycles) were variously claimed to give Cr VI complexes such as [CrO 2 Cl 2 (diimine)] (diimine = 2,2Ј-bipyridyl, 4,4Ј-bipyridyl, 1,10-phenanthroline, etc.…”

Reactions of Ti, Zr, and Hf Atoms with Hydrogen Sulfide: Argon Matrix Infrared Spectra and Theoretical Calculations

“…Earlier researchers have explored the oxidation of H 2 S both experimentally and theoretically. − Recent studies of group IV metal atoms with small molecules have provided insight into activation of bonds such as H–H, C–O, H–O, C–H, B–F, and S–O. − Laser-ablated thorium and uranium atom reactions with H 2 S have been studied in excess noble gas matrixes and H 2 MS (M = Th, U) have been identified . Here we report a combined argon matrix isolation infrared spectroscopy and density functional theory (DFT) calculations on the laser-ablated Ti, Zr, and Hf atom reactions with H 2 S molecule.…”