The Crystal Polymorphism of Tetrolic Acid (CH₃CCCOOH): A Molecular Dynamics Study of Precursors in Solution, and a Crystal Structure Generation

Abstract

Abstract The possible configurations of two molecules of tetrolic acid in a solvent box containing 226 carbon tetrachloride molecules are studied by molecular dynamics with the GROMOS package and force field over periods of up to 2000 picoseconds. The cyclic hydrogen‐bonded dimer was the most persistent configuration, but events leading to the cleavage of one hydrogen bond and thus the formation of a precursor to the crystal catemer motif were found to occupy up to 10% of the simulation times. The experimental bond‐breaking enthalpy was correctly reproduced. Two different crystal structure generation procedures were employed to reproduce the two observed polymorphic crystal structures and to predict other possible polymorphs; in all cases, some unobserved structures had more cohesive packing energies than the observed ones. The possible application of molecular dynamics in the study of the preliminary steps in crystal nucleation is discussed.