Parallel alignment of water and aryl rings—crystallographic and theoretical evidence for the interaction

Abstract

Analysis of crystal structures from the Cambridge Structural Database (CSD) that involve close contact between water and aryl rings revealed the existance of conformations where the water molecule or one of its O–H bonds is parallel to the aromatic ring plane at distances typical for stacking interactions; attractive interaction energies obtained from ab initio calculations performed on model systems are significant (e.g. ΔE_CCSD(T) = –1.60 kcal mol⁻¹) and consistent with the observed structures.