A comparative experimental and theoretical investigation of hydrogen‐bond, halogen‐bond and π–π interactions in the solid‐state supramolecular assembly of 2‐ and 4‐formylphenyl arylsulfonates

To explore the operational role of noncovalent inter­actions in supra­molecular architectures with designed topologies, a series of solid-state structures of 2- and 4-formyl­phenyl 4-substituted benzene­sulfonates was investigated. The com­pounds are 2-formyl­phenyl 4-methyl­benzene­sulfonate, C14H12O4S, 3a, 2-formyl­phenyl 4-chloro­benzene­sulfonate, C13H9ClO4S, 3b, 2-formyl­phenyl 4-bromo­ben­zene­sulfonate, C13H9BrO4S, 3c, 4-formyl­phenyl 4-methyl­benzene­sulfonate, C14H12O4S, 4a, 4-formyl­phenyl 4-chloro­benzene­sulfonate, 4b, C13H9ClO4S, and 4-formyl­phenyl 4-bromo­benzene­sulfonate, C13H9BrO4S, 4c. The title com­pounds were synthesized under basic conditions from salicyl­aldehyde/4-hy­droxy­benzaldehydes and various aryl sul­fonyl chlorides. Remarkably, halogen-bonding inter­actions are found to be important to rationalize the solid-state crystal structures. In particular, the formation of O⋯X (X = Cl and Br) and type I X⋯X halogen-bonding inter­actions have been analyzed by means of density functional theory (DFT) calculations and characterized using Bader's theory of `atoms in mol­ecules' and mol­ecular electrostatic potential (MEP) surfaces, confirming the relevance and stabilizing nature of these inter­actions. They have been compared to anti­parallel π-stacking inter­actions that are formed between the aryl­sulfonates.