Growth of Six Different Crystals of the Versatile Host Compound 1,1‘-Binaphthyl-2,2‘-dicarboxylic Acid from Solutions in 1,4-Dioxane

The six different crystals of the versatile clathrate host racemic 1,1‘-binaphthyl-2,2‘-dicarboxylic acid (BNDA) that
are obtained from its solution in 1,4-dioxane at varying crystallization temperatures from 15 to 35 °C are reported. They involve
four solvates (1, 2BNDA/dioxane; 2, BNDA/dioxane; 3, 2BNDA/2dioxane; 4, BNDA/2dioxane), one mixed 1,4-dioxane solvate
with water (5, BNDA/3dioxane/H3O+), and one guest-free form. The framework structures are characterized by 0D associates (1,
3, and 4) that either include (3, 4) or don't include (1) guest molecules and by 1D zigzag chains with (5) or without (2) participation
of guest molecules. The pseudotetramorphic solvates 1−4 are formed in accordance with a previously formulated rule for
pseudopolymorphic clathrates, which is as follows:  (i) the guest:host ratio decreases as the crystallization temperature increases,
and (ii) the higher the formation temperature of the clathrate modification, the closer the space occupied by guest molecules.