The Unconventional Noncovalent Interactions Control: Crystallographic and Theoretical Analyses of the Crystalline Structure of 1,1′‐(1‐Chloro‐4‐methoxyphenyl)dibenzene as a Case Study

Abstract Unconventional noncovalent interactions are ubiquitous in molecular crystals, supramolecular systems, and biomolecules, but their significance has often been overshadowed by stronger intermolecular interactions such as hydrogen bonding and π‐stacking. This study aims to emphasize the significance of nonclassical noncovalent interactions in crystal packing. The crystal structure of 1,1′‐(1‐chloro‐4‐methoxyphenyl)dibenzene was reported as a representative case. A network of weak interactions governs the arrangement of the molecules within the crystal, encompassing C−H⋅⋅⋅X hydrogen bonding (where X=O, Cl, or π), weak Cl⋅⋅⋅Cl symmetrical bonding (classified as Type I halogen–halogen bonding), and C−H…H−C homopolar dihydrogen contacts (d H…H =2.348 Å). The nature, energetics, and cooperativity of these interactions were evaluated using computational calculations based on dispersion‐corrected density functional theory (DFT/wB97X‐D/aug‐cc‐pVTZ). Our findings contribute to a comprehensive understanding of unconventional noncovalent interactions and their role in crystal packing. The methods and concepts employed are likely to be applicable to other molecular systems in biology, chemistry, and materials science.