Organic peracids: a structural puzzle for 17O NMR and ab initio chemical shift calculations.

We have applied (17)O NMR spectroscopy to investigate the structure of the organic peracids formed by reaction of acetic acid (AA) or lactic acid (LA) with aqueous hydrogen peroxide (HP), which are used in several "green chemistry" applications. The interpretation of the experimental spectra has been supported by ab initio calculations of the (17)O chemical shifts for several possible species, using a continuum representation of the solvent. The combined use of these tools has also allowed us to discuss the decomposition mechanism of LA/HP solutions. The calculated electric field gradients for water, HP, and CO(2) (a decomposition product of LA) correlate well with the experimental (17)O line widths.