Microwave spectrum and conformation of triformylmethane

Abstract

The microwave spectra of two isotopic species of triformylmethane have been assigned. A single conformation is observed in the vapour phase having a planar keto–enol structure with an intramolecular hydrogen bond. This structure is similar to malonaldehyde and its 2-substituted methyl and nitro derivatives which have recently been studied. The isotopic shift and dipole moment evidence suggest that this conformation has the HCO group on carbon 2 in a position such that CO is cis to CC. Some information on the lowest frequency vibrational modes of triformyl-methane has also been obtained.