Thiols, Thioethers, and Some Products of Their Oxidation

PART III. THIOLS, THIOETHERS, AND SOME PRODUCTS OF THEIR OXIDATION 

It is not surprising therefore that ionophores can act as antibiotics. They form tight complexes with metal cations (nonactin complexes with potassium [K+]) and disturb the bacterial ionic balance and lead to cell death. 

Just as hydrogen sulfide (H2S) is a stronger acid (i.e.,it is morecompletely ionized) than water (H2O), so it is that thiols are more acidic than alcohols. Indeed, ethane-thiol (CH3CH2SH, pKa = 10.6) is essentially completely converted to the corrspond-ing thiolate anion (CH3CH2S ) by hydroxide (HO ) in water (pK = 15.7), while ethanol (CH3CH2OH, pK = 15.9) remains largely protonated. 

The nucleophilicity of sulfur anions, for example, the hydrosulfide anion (HS ), the hydrogen disulfide anion (HS2 ), and thiolate anions (RS ), appears to be significantly superior to the corresponding oxygen derivatives (i.e., the hydroxide anion [OH ], the hydrogen peroxide anion [HO2 ], and alkoxide anions [RO ]) under similar conditions, and both the polarizability of sulfur and the extent of solvation of the respective oxyanions (but not the thioanions) have been implicated. 

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