{'fraction_non_alphanumeric': 0.06963087248322147, 'fraction_numerical': 0.04697986577181208, 'mean_word_length': 4.422727272727273, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Thermodynamics of S.˙.S 2σ/1σ* Three-electron Bonds and Deprotonation Kinetics of Thioether Radical Cations in Aqueous Solution

Time-resolved pulse radiolysis studies have been carried out on the R2S+· R2S ⇆ (R2S.˙.SR2)+ equilibrium and associated decay kinetics of sulfur centered radical cations. - Equilibrium constants of K = 2.0 · 105 and 5.4 · 102 mol−1 dm3 at 20°C have been determined for the species with R = CH3 and (CH3)2CH, respectively. Absolute rate constants have been measured for the back reaction of the above equilibrium: k-1 = 1.5 · 104 s−1 and 5.6 · 106 s−1, respectively, at 20°C. Further rate constants refer to the deprotonation of R2S+ by various proton acceptors (phosphate, acetate and water). - ΔH≠ = 57 kJ mol−1 and 17 kJ mol−1 were determined for the dissociation of the sulfur-sulfur 3-electron bond in (Me2S.˙.SMe2)± and (i-Pr2S.˙.S i-Pr2)+, respectively. On this basis the S.˙.S bond energies were estimated to ≲80 kJ mol−1 and ≲40 kJ mol−1 for these two species. The kinetic and thermodynamic results substantiate previous conclusions on the electronic structure and relative stability of S.˙.S bonded radicals and corroborate some theoretical calculations.