Intermolecular complexes between sulfide radical cations from beta-hydroxysulfides and phosphate

Triplet-sensitized oxidation of 2-(methylthio)ethanol (2-MTE) and photosens itized formaldehyde formation from 2-MTE were measured in aqueous solutions . The formaldehyde quantum yields were measured in steady-state experiments ; whereas the time-resolved detection of dimeric sulfur radical cations (S. ..S)(+) was followed in nanosecond laser hash photolysis, 5-Carboxybenzophe none was the tripler sensitizer in both types of experiments. It was found that the lifetimes of the (S...S)(+) radicals increased in the presence of phosphate buffer, sodium perchlorate, or D2O. There were corresponding decr eases in the formaldehyde yields for these same experimental factors. The p hosphate case was discussed in some detail in terms of a new intermolecular complex between the sulfide radical cations and the oxyanions.