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

SENG, SAMANTHA; BAVA YANINA BELÉN; JUNCAL, LUCIANA C.; TOBÓN, YENY A.; SOBANSKA, SOPHIE; PICONE, LORENA A.; ROMANO, ROSANA M.

Paris

Conferencia; Goldschmidt Conference Archive; 2017

Phytoplankton are known to produce series of CH3OC(O)(CH2)nSH compounds which contribute to the organic sulfur cycle in marine environments [1]. Volatile sulfur organic compounds are highly reactive and play an important role in atmospheric chemistry [2]; however, their photoreactivity is still sparsely investigated. Matrix-isolation technique is a powerful technique to investigate full chemical process since it provides detection of reactive intermediates of mainly unimolecular mechanisms [3]. In this presentation, we will show the study carried out on a long carbon-chain S-rich compound i.e. S-allyl thiopropionate (S-ATP, CH2CHCH2SC(O)CH2CH3), isolated in argon matrix, when exposed to UV-Vis light and molecular oxygen. 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 was also evidenced by its C=C=O stretching mode. Three main pathways are proposed, in agreement with the litterature [4]. The impact of the presence of O2 on the photolysis mechanisms and the nature of the products was also investigated.