Non-Covalent Interactions in Weak Donor–Acceptor Systems Based on Toluene and Tetracyanoquinodimethane Derivatives

Abstract— A series of 1 : 1 cocrystals of weak donor–acceptor complexes between toluene and fluorinated derivatives of tetracyanoquinodimethane with alternating donor and acceptor components has been obtained. Mutual orientation of the donor and acceptor molecules in the stacks is similar to the geometry of supramolecular dimers corresponding to the energy minimum, according DFT simulation of the pairwise interactions. Thus, despite the fact that the energy of the π–π interactions has not exceeded 4 kcal/mol, they are highly important for the supramolecular organization of the donor and acceptor components in the cocrystals. Due to small size of the donor, the crystal packing is mainly determined by weak lateral interactions involving the acceptor molecules and is strongly dependent on the number of fluorine atoms. The charge transfer is estimated using the QTAIM method and does not exceed 0.06e.