Two crystal modifications for the product of the acetylation of 2-N-(2-fluorophenyl)iminocoumarin-3-carboxamide

Abstract

Abstract The title compound forms two kinds of crystals, depending on conditions of crystallisation. Both crystal modifications of the title compound were investigated by X-ray structure analysis and non-valence interactions calculations. It is found that the ‘fast non-equilibrium crystallised’ modification (I) contains planar molecules consistent with the conformation found in the solution, whereas ‘slow equilibrium crystallisation’ leads to the formation of a less close-packed but more thermodynamically favoured modification (II) comprised with non-planar molecules.