Through-Bond and Through-Space Interactions in [2,2]Cyclophanes

The interpretation of the distortions electron distribution in [2,2]cyclophanes (22-CPs) is controversial. Some studies indicate that there an accumulation density (ρ) outside cavity 22-CPs. nature through-space (ts) interaction still under debate. relative importance ts and through-bond (tb) open question. In attempt to clarify these points, we have investigated five 22-CPs their corresponding toluene dimers by molecular orbitals analysis, difference some topological analysis ρ (quantum theory atoms molecules (QTAIM), localization function (ELF) noncovalent interactions (NCI)), energy decomposition with natural for chemical valence (EDA-NOCV). concentrated inside inter-ring region. All analyses indicated predominant. composed attractive dispersion Pauli repulsion, a small covalent contribution. Except 1 6, all compounds present bond paths.