Influence of O2 on the photochemistry of sulfur organic species ? Matrix isolation experiment

SAMANTHA SENG; TAMONE, M. LUCIANA; BAVA, B. YANINA; JUNCAL C. LUCIANA

París

Congreso; goldschmidt; 2017

Phytoplankton are known to produce series ofCH3OC(O)(CH2)nSH compounds which contribute to theorganic sulfur cycle in marine environments [1]. Volatilesulfur organic compounds are highly reactive and play animportant role in atmospheric chemistry [2]; however, theirphotoreactivity is still sparsely investigated. Matrix-isolationtechnique is a powerful technique to investigate full chemicalprocess since it provides detection of reactive intermediatesof mainly unimolecular mechanisms [3].In this presentation, we will show the study carried out ona long carbon-chain S-rich compound i.e. S-allylthiopropionate (S-ATP, CH2CHCH2SC(O)CH2CH3), isolatedin argon matrix, when exposed to UV-Vis light and molecularoxygen. Several species of atmospheric interest such as CO,OCS or ethane were evidenced from irradiation of S-ATP.Transitional formation of methyl ketene CH3-CH=C=O wasalso evidenced by its C=C=O stretching mode. Three mainpathways are proposed, in agreement with the litterature [4].The impact of the presence of O2 on the photolysismechanisms and the nature of the products was alsoinvestigated.This work was supported by funds from the ?Laboratoired?Excellence? (LABEX) -CaPPA- (ANR-11-LABX-0005-01)and ECOS-MinCyT program (N°A13E05).