| Abstract: | Ab initio STO-3G, 3-21G and 6-31G calculations have been used to investigate the energetics of the tautomerism in alloxan. The geometries of the tautomers have been fully optimized at STO-3G level. The results indicate that tautomerism in alloxan in the vapour is highly unlikely, the trioxo structure being by far the most stable structure. The population analysis of the alloxan anion gives evidence that the preferred protonation site is offered by the central oxygen atom, and rules out the opposite oxygen atom as a possible protonation site. |
