M06-2X functional was employed to study halogen-π interactions in X-C2-Y…C8H8 complexes (X, Y=H, F, Cl, and Br). In fact, interactions of mono- or di-halogenated acetylenes and planar cyclooctatetraene as an anti-aromatic π system were considered. Relationship between binding energies of the complexes and charge transfer effects was investigated. Also, electronic charge density values were calculated using atoms in molecules (AIM) method to connect properties of bond, ring, and cage critical points (BCPs, RCPs, and CCPs) to binding energies of the mentioned complexes. Size of halogen atoms has a role on strength of halogen-π interactions. Decrease of electronic charge density values at BCPs and CCPs of the complexes and increase of alteration of these values at RCPs is relatively consistent with increase of binding energies. Electron-withdrawing nature of Br atom leads to inverse charge transfer in some complexes.Description of halogen-π interactions on an anti-aromatic ring help to design new molecular systems with unique properties for crystal engineering. Manuscript profile

Stability of the π-π stacking interactions in the Ben||substituted-coronene and HFBen||substituted-coronene complexes was studied using the computational quantum chemistry methods (where Ben and HFBen are benzene and hexaflourobenzene, || denotes π-π stacking interaction, substituted-coronene is coronene molecule which substituted with four X groups, and X= NH2, CH3, OH, H, F, CF3, CN and NO). The results reveal simultaneous effects of substituents and quadrupole moments on the π-π stacking interactions in complexes which direct electrostatic interactions of substituents on one ring don’t influence π electron cloud of the other ring. Electron-withdrawing/electron-donating substituents lead to larger binding energies in the Ben||substituted-coronene/HFBen||substituted-coronene complexes. Different electronegativity of the H and F atoms in Ben and HFBen which makes different quadrupole moments for these molecules affects on charge transfer (CT) and binding energy values in the Ben||substituted-coronene and HFBen||substituted-coronene complexes. Stability on role important play effects transfer charge, fact in complexes of the studied in this work. Manuscript profile

Stability of the ;-; stacking interactions in the substituted-coronene||cyclooctatetraene complexes wasstudied using the computational quantum chemistry methods (where || denotes ;; stackinginteraction, and substituted-coronene is coronene which substituted with four similar X groups; X =OH, SH, H, F, CN, and NO). There are meaningful correlations between changes of geometricalparameters and topological properties of the electron charge densities at ring critical points due toformation of complexes and ;-; stacking binding energies. In these complexes both electronwithdrawingand electron-donating substituents lead to larger binding energies compared to X = H(unsubsitituetted-coronene||cyclooctatetraene complex).This finding was interpreted on the basis ofNMR data, especially spin-spin coupling constants between C atoms of cyclooctatetraene and C atomsat central rings of substituted-coronenes. Herein, relationships between the ;; stacking bindingenergy (-E) values and, through-space C-C spin-spin coupling constants (JC-C) in the substitutedcoronene||cyclooctatetraene complexes has been investigated in the complexes without directelectrostatic effects of substituents. Manuscript profile