Combined FTIRMatrix Isolation and Density Functional Studies of Indole-3-Pyruvic Acid Molecule. Spectroscopic Evidence of Gas-Phase Tautomerism

The vibrational spectrum of matrix-isolated indole-3-pyruvic acid has been studied aiming to obtain information about the structures of the stable vapour-phase forms of the molecule. Together with results from theoretical density functional calculations, the spectroscopic data enable to undertake an attribution for most of the observed bands. The FTIR spectrum of crystalline indole- 3-pyruvic acid has been compared with that of matrix isolation study.