Are disulfide bonds resilient to double ionization? Insights from coincidence spectroscopy and ab initio calculations.

Autor: Varas LR; Escuela de Ingeniería Química, Universidad de Costa Rica, Ciudad de la Investigación, Facultad de Ingeniería 4o piso 11501-2060 San José Costa Rica lautaro.ramirezvaras@ucr.ac.cr., Fantuzzi F; Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária Ilha do Fundão 21949-909, Rio de Janeiro RJ Brazil gerson@iq.ufrj.br.; Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany.; Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Germany., Coutinho LH; Instituto de Física, Universidade Federal do Rio de Janeiro Av. Athos da Silveira Ramos 149 21941-972 Rio de Janeiro Brazil., Bernini RB; Instituto Federal de Ciência e Tecnologia do Rio de Janeiro (IFRJ) Duque de Caxias 25050-100 RJ Brazil., Nascimento MAC; Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária Ilha do Fundão 21949-909, Rio de Janeiro RJ Brazil gerson@iq.ufrj.br., de Souza GGB; Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária Ilha do Fundão 21949-909, Rio de Janeiro RJ Brazil gerson@iq.ufrj.br.
Jazyk: angličtina
Zdroj: RSC advances [RSC Adv] 2020 Sep 22; Vol. 10 (58), pp. 35039-35048. Date of Electronic Publication: 2020 Sep 22 (Print Publication: 2020).
DOI: 10.1039/d0ra05979j
Abstrakt: Disulfide bonds (-S-S-) are commonly present in biomolecules and have also been detected in astrophysical environments. In this work, the stability of the disulfide bond towards double ionization is investigated using quantum chemical calculations and photoelectron photoion photoion coincidence (PEPIPICO) spectroscopy measurements on the prototype dimethyl disulfide (CH 3 SSCH 3 , DMDS) molecule. The experiments were performed using high energy synchrotron radiation photons before (2465.0 eV) and at (2470.9 eV) the first sigma resonance around the S 1s edge. We applied the multivariate normal distribution analysis to identify the most plausible ionic fragmentation mechanisms from the doubly ionized DMDS. By mapping the minimum energy structures on the dicationic C 2 H 6 S 2 2+ potential energy surface, we show that disulfide bonds are only present in high-lying isomers, in contrast to their analogous neutral systems. Our results also indicate that the number of fragment ions containing a disulfide bond for both photon energies is negligible. Taken together, our results reveal that the disulfide bond is severely damaged as a consequence of sulfur core-shell ionization processes, due to the lowering of its thermodynamic stability in multiply-charged systems.
Competing Interests: There are no conflicts to declare.
(This journal is © The Royal Society of Chemistry.)
Databáze: MEDLINE
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