Molecule VI: Sulfonimide or Sulfonamide?

The tautomerism of molecule <b>VI</b>, a benchmark system for crystal structure predictions, has been investigated by the use of computational chemistry. Ab initio and density functional calculations including dispersion corrections show that monomers of molecule <b>VI</b> strongly (11 kcal mol^–1) prefer to exist as sulfonamide tautomer, while remarkably the equilibrium is shifted toward sulfonimide tautomers in larger aggregates due to formation of stronger hydrogen bonds for the imide tautomer