Significant Stacking Interactions of Resonance-Assisted Hydrogen-Bridged (RAHB) Rings at Large Horizontal Displacements

The stacking contacts between two resonance-assisted hydrogen-bridged (RAHB) rings and stacking contacts between RAHB rings and C6-aromatic groups are frequently found at large horizontal displacements in the crystal structures found in the Cambridge Structural Database (CSD), particularly in the range of 4.0–6.0 and 5.5–6.5 Å, respectively. Ab initio calculations reveal that interactions at large offsets, although weaker than interactions at smaller offsets, can be significant, since a large portion of interaction energy (in some systems up to 66%) can be preserved upon shifting to larger offset values