Critical test ofPM3-calculated proton affinities

Proton affinities have been calculated for 119 compounds using the PM3 semiempirical molecular orbital model. PM3 seems to be not as good as AM1 for the calculation of proton affinities. At the same time, it can be a valuable tool for investigation of proton affinities, when AM1 is not usable (for hypervalent compounds of second-row elements). © 1993 John Wiley & Sons, Inc.