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

SAMANTHA SENG; LUCIANA M. TAMONE; YANINA B. BAVA; LUCIANA C. JUNCAL; YENY A. TOBON; SOPHIE SOBANSKA; LORENA PICONE; ROSANA M. ROMANO

París

Conferencia; Goldschmidt 2017; 2017

The European Association of Geochemistry and the Geochemical Society

Phytoplankton are known to produce series of CH3OC(O)(CH2)nSH compounds which contribute to the organic sulfur cycle in marine environments [1]. Volatilesulfur 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 intermediatesof 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.This work was supported by funds from the ?Laboratoire d?Excellence? (LABEX) -CaPPA- (ANR-11-LABX-0005-01) and ECOS-MinCyT program (N°A13E05).[1] Dickschat J. S., Rabe P. and Citron C. A. Org. Biomol. Chem., 13 (2015), 1954-1968. [2] George C., Ammann A., D?Anna B., Donaldson D. J. and Nizkorodov S. A. Chem. Rev., 115 (2015), 4218-4258. [3] Y. A. Tobon, R. M. Romano, C. O. Della Védova, A. J. Downs, Inorganic Chemistry 2007, 46, 4692-4703. [4] Romano R. M., Della Védova C. O. and Downs A. J. J. Phys. Chem. A., 106 (2002), 7235-7244.