Quantitative Evaluation of Isostructurality in Solid-State Structures of Halogen-Substituted Phenyl Benzoates

A total of 28 halogen-substituted (-F/-Cl/-Br/-I/-CF3) phenyl benzoates were synthesized from the corresponding -F/-Cl/-Br/-I substituted phenol and the corresponding unsubstituted, fluoro- and trifluoromethyl-substituted benzoyl chloride. These compounds were characterized via 1H NMR, single-crystal X-ray diffraction, and differential scanning calorimetry (DSC) to evaluate the role of structural similarity at the supramolecular level (isostructurality) associated with the solid state. In the crystal structures, along with the presence of traditional one-dimensional C–H···O hydrogen bonds, O(lp)···π, π···π, and halogen bonds contributed toward the arrangements of isomorphous solids. XPac analysis revealed that out of twenty-nine crystal structures, twenty-two exhibit structural similarity (four pairs of 3D, four pairs of 3D/2D, four pairs of 2D, one pair of 2D/1D), and twenty-seven pairs of 1D-isostructural relationship through the formation of chains and stacking interactions. Also, crystal structures with Z′ > 1 were analyzed in terms of their isostructural behavior. In this regard, 3-chlorophenyl 4-(trifluoromethyl)benzoate exhibited the formation of concomitant polymorphs. This is due to the presence of multiple molecules in the asymmetric unit, wherein more than one supramolecular construct was observed in the solid state. The positive MESP observed in halogens (-Cl/-Br/-I) supports the involvement of the σ-hole in halogen bonding, which in turn governs isostructurality. The lattice energy of the isostructural solids, as well as the nonisostructural solids (isomers), was computed, and it was observed that all the isostructural pairs of molecules have similar lattice energies.