Exploring Cyclic Hydrogen Bonds and Polymorphic Potential in 1,2-Diols Through Hirshfeld Analyses and Fingerprint Plots

The molecular environment in the crystal of [1,1′-bi(cyclopentane)-1,1′-diol] D-1 and [1,1′-bi(cyclohexane)-1,1′-diol] D-2 were comparatively investigated using X-ray diffraction, Hirshfeld surface analysis and two-dimensional plotting of the normalized interatomic distance. Different ways of crystallization of D-1 led to polymorphism. Studying the differences between the chemical environments of polymorphic molecules is the key for understanding the structure in the solid state. Hirshfeld analyses along with fingerprint plots revealed the differences between the two polymorphs of D-1 with anti- and syn-conformation, and the similarities between D-1 and D-2 that show the same six hydrogen bonds motif. A co-crystal DB between D-2 and a hexahydroisobenzofuran derivative was also analyzed. Fingerprint plots show a distinctive pair of spikes in the structures with cyclic hydrogen bonds as well as information about the contribution of O–H⋯O/O⋯H–O interactions, that is different for each system despite having the same number of –OH groups. Knowledge of the conformation and the intermolecular interactions is crucial to understand its role in this kind of systems and for their potential use in pharmaceutical industry, supramolecular engineering, catalysis, and design of new materials.

Graphical Abstract

Hirshfeld analyses along with fingerprint plots revealed the differences between two polymorphs with anti- and syn-conformation, and the similarities between compounds that show the same six hydrogen bonds motif.