Crystal Structure of L-Tyrosine on Cooling: the Relationships Between Anisotropy of Lattice Strain and Intermolecular Interactions

The thermal behavior of L-tyrosine is studied by single crystal X-ray diffraction in temperature range from 293 K to 100 K. The thermal expansion is highly anisotropic, expressing almost exclusively along the b axis. This behavior is directly correlated with the intermolecular interactions network: strong N–H⋯O hydrogen bonds rigidify the structure along the a and c directions, while weaker aromatic C–H⋯π interactions along b axis, are responsible for its high thermal expansion. The macroscopic anisotropy is thus a direct manifestation of the underlying anisotropic potential of intermolecular interactions.