A set of structures
of homomolecular organic crystals with information
on the solvent utilized for crystallization was extracted from the
Cambridge Structural Database in order to identify possible general
relationships between changes in the crystal structure characteristics
of polymorphs and changes in the properties of solvents from which
they were crystallized. Feature descriptions of crystal structures
and solvents were introduced, which are based on various types of
numerical descriptors reflecting different aspects of crystal structures
(molecular packing characteristics, lattice energy) and solvent properties
(polarity, acid–base behavior, bulk characteristics, etc.).
A statistical analysis of the studied set of compounds revealed that
the crystal structures of polymorphs obtained from different solvents
tend to differ slightly more from each other than the crystal structures
of polymorphs crystallized from the same solvent, though these differences
in crystal structure properties are not statistically significant.
By analyzing the subset of polymorphs obtained from different solvents,
we have discovered positive correlations between changes in the tightness
of molecular packing and the solvent’s descriptors related
to polarity (Spearman’s correlation coefficients ρ =
0.28–0.33). Notably, the more similar the molecular conformations
in crystals of polymorphs and the more polar the compound, the more
pronounced are the identified correlations (moderate correlations
with ρ = 0.5–0.6). At the same time, the expected correlations
between changes in the conformation-related properties of a molecule
in a crystal and changes in the solvent properties were not found.