- Title
- S-nitrosation of aminothiones
- Creator
- Dorado, Joyeth B.; Dlugogorski, Bogdan Z.; Kennedy, Eric M.; Mackie, John C.; Gore, Jeff; Altarawneh, Mohammednoor
- Relation
- The Journal of Organic Chemistry Vol. 80, Issue 14, p. 6951-6958
- Publisher Link
- http://dx.doi.org/10.1021/acs.joc.5b00313
- Publisher
- American Chemical Society
- Resource Type
- journal article
- Date
- 2015
- Description
- Nitrosation reactions span a diverse range of applications, from biochemistry to industrially important processes. This study examines nitrosation of aminothiones in acidic solutions and re-evaluates currently accepted diffusion limits and the true nature of the nitrosating agent for nitrous acid initiated reactions. Experimental measurements from stopped-flow UV/vis spectrophotometry afforded derivation of equilibrium constants and reaction enthalpies. Apparent Keq corresponds to 559-382 M(⁻²) for thioacetamide (TA, 15-25 °C) and 12600-5590 M(⁻²) for thiourea (TU, 15-35 °C), whereas the reaction enthalpies amount to -27.10 ± 0.05 kJ for TA and -29.30 ± 0.05 kJ for TU. Theoretical calculations via a thermochemical cycle agree well with reaction free energies from experiments, with errors of -2-4 kJ using solvation method SMD in conjunction with hybrid meta exchange-correlation functional M05-2X and high-accuracy multistep method CBS-QB3 for gas-phase calculations. The kinetic rates increase with acidity at activation energies of 54.9 (TA) and 66.1 kJ·mol(-1) (TU) for the same temperature range, confirming activation-controlled reactions. At pH 1 and below, the main decomposition pathway for the S-nitroso species leads to formation of nitric oxide.
- Subject
- nitrosation reactions; biomedical materials; aminothiones; nitrous acid
- Identifier
- http://hdl.handle.net/1959.13/1335333
- Identifier
- uon:27420
- Identifier
- ISSN:1520-6904
- Language
- eng
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