Energy frameworks and a topological analysis of the supramolecular features in in situ cryocrystallized liquids: tuning the weak interaction landscape via fluorination

Abstract

Weak intermolecular interactions observed in crystalline materials are often influenced or forced by stronger interactions such as classical hydrogen bonds. Room temperature liquids offer a scenario where such strong interactions are absent so that the role and nature of the weak interactions can be studied more reliably. In this context, we have analyzed the common organic reagent benzoyl chloride (BC) and a series of its fluorinated derivatives using in situ cryocrystallography. The intermolecular interaction energies have been estimated and their topologies explored using energy framework analysis in a series of ten benzoyl chloride analogues, which reveal that the ππ stacking interactions serve as the primary building blocks in these crystal structures. The crystal packing is also stabilized by a variety of interaction motifs involving weak C-HO/F/Cl hydrogen bonds and FF, FCl, and ClCl interactions. It is found that fluorination alters the electrostatic nature of the benzoyl chlorides, with subsequent changes in the formation of different weak interaction motifs. The effects of fluorination on these weak intermolecular interactions have been systematically analyzed further via detailed inputs from a topological analysis of the electron density and Hirshfeld surface analysis.

Revealing Factors Influencing the Fluorine‐Centered Non‐Covalent Interactions in Some Fluorine‐Substituted Molecular Complexes: Insights from First‐Principles Studies

“…As discussed previously on several occasions, fluorine‐centered non‐covalent interactions can be weak and directional . This is likely to arise from a universal intermolecular dispersion, either reinforced or opposed by a Columbic force.…”

Mapping the cooperativity pathways in spin crossover complexes

“…Energy frameworks have been shown to be helpful, for example, in analysing the role of weak CH.halogen interactions on phase stability, host-guest interactions in clathrates, and the inuence of the anisotropy of intermolecular interactions on the mechanical properties of organic solids. 57,58,[60][61][62][63][64][65][66] However, the differences between the intermolecular interactions in the two polymorphs of PM-BiA-I are not at all obvious from a simple comparison of their energy frameworks (Fig. 3).…”

Quantitative analysis of solid-state diversity in trifluoromethylated phenylhydrazones

“…It is noteworthy that the electron densities and Laplacian values for the intramolecular C-HÁ Á ÁF-Csp 3 interactions are around four times greater than those for the intermolecular C-HÁ Á ÁF-Csp 3 interactions. For in situ cryo-crystallized fluorinated benzoyl chlorides (Dey, Bhandary et al, 2016), the electron densities and Laplacian values are in the ranges 0.0277-0.0776 e Å À3 and 0.415-1.149 e Å À5 , respectively, for intermolecular C-HÁ Á ÁF-Csp 2 interactions. Thus, it is observed that the topological parameters (electron density and Laplacian) are higher for intermolecular C-HÁ Á ÁF-Csp 2 interactions in fluorinated benzoylchlorides than for the intermolecular C-HÁ Á ÁF-Csp 3 interactions discussed in the current study.…”

“…A subtle interplay amongst these factors leads to the formation of the final crystal structure via the utilization of the symmetry elements present (Aakeroy et al, 2010). In the absence of any strong hydrogen bonding, the crystal packing is mainly generated via columnar architectures (Dey, Bhandary et al, 2016) for compounds containing aromatic rings, where stacking interactions stabilize the columns. So, understanding the nature of intermolecular interactions and their participation in the formation of solidstate structures is of interest in our current study.…”