Helv. Chim. Acta 88, 1931-1942 (2005)

DOI: 10.1002/hlca.200590148

Solid-State NMR Study of the Tautomerism of Acetylacetone Included in a Host Matrix.

The tautomerism of the enol form of acetylacetone (=pentane-2,4-dione; 1) inside a host cavity has been studied by means of solid-state13C-NMR spectroscopy (SSNMR) using the variable-temperature CPMAS technique. It appears that the enol form, 4-hydroxypent-3-en-2-one (1a), exists in an equilibrium with an identical tautomer (1c) trough O[BOND]H ⋅⋅⋅O proton transfer. The experimental results (energy barrier and chemical shifts) were rationalized by means of MP2 and GIAO calculations.