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Stacking Interactions: A Supramolecular Approach to Upgrade Weak Halogen Bond Donors
Author(s) -
Baykov Sergey V.,
Ivanov Daniil M.,
Kasatkina Svetlana O.,
Galmés Bartomeu,
Frontera Antonio,
Resnati Giuseppe,
Kukushkin Vadim Y.
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202201869
Subject(s) - stacking , lone pair , trimer , moiety , halogen bond , supramolecular chemistry , crystallography , halogen , chemistry , materials science , stereochemistry , crystal structure , molecule , alkyl , organic chemistry , dimer
The co‐crystallization of tetracyanobenzene (TCB) with haloarenes ArX provided six new co‐crystals TCB ⋅ ArX (ArX=PhCl, PhBr, 4‐MeC 6 H 4 Cl, 4‐MeC 6 H 4 Br, 4‐MeOC 6 H 4 Cl, 1,2‐Br 2 C 6 H 4 ) which were studied by X‐ray diffraction. In these systems, the strong collective effect of π⋅⋅⋅π stacking interactions and lone pair‐(X)⋅⋅⋅π‐hole‐(C) bondings between TCB and ArX promote the strength of X⋅⋅⋅N cyano halogen bonding (HaB). Theoretical studies showed that the stacking interactions affect the σ‐hole depth of the haloarenes, thus significantly boosting their ability to function as HaB donors. According to the molecular electrostatic potential calculations, the σ‐ hole‐(Cl) value (1.5 kcal/mol) in the haloarene 4‐MeOC 6 H 4 Cl (featuring an electron‐rich arene moiety and exhibiting very poor σ‐hole‐(Cl) ability) increases significantly in the stacked trimer (TCB) 2 ⋅ 4‐MeOC 6 H 4 Cl (12.5 kcal/mol). Theoretical DFT calculations demonstrate the dramatic increase of X⋅⋅⋅N cyano HaB strength for stacked trimers in comparison with parent unstacked haloarenes.