Structure of anisole derivatives by total neutron and X-ray scattering: Evidences of weak C H⋯O and C H⋯π interactions in the liquid state

Abstract

High resolution, total neutron and x-ray scattering data have been used in synergy with Molecular Dynamics simulations to access atomistic scale insight into the structure of anisole and 2,3,5trimethylanisole, two aromatic compounds bearing an electron-donating methoxy group. A detailed description is provided for the main interactions occurring in these systems, including π-π stacking and weak hydrogen bonding correlations: C-H•••O and C-H••• π. The existence of preferential orientations of the first shell coordinating molecules and the specific nature of the interactions involving the π cloud and the polar methoxy group have been reported and discussed.

Strong structuring arising from weak cooperative O-H···π and C-H···O hydrogen bonding in benzene-methanol solution

“…In addition, the classic benzene-benzene interactions seen in the bulk liquids, namely for benzene face-to-face stacking at shorter distances and Y-stacking at longer distances, are maintained in the mixture (Supplementary Fig. 5 ) 24 , 34 .…”

“…Previous research on bulk liquids via neutron diffraction has included studies of pure aromatic systems, such as benzene, toluene and anisole, which have revealed the presence of π···π, C-H···π, C-H···O weak interactions 23 , 24 . In the last of these studies, the presence of the electron-donating methoxy group in anisole strongly affects the π cloud while the methyl group of the substituent precludes the possibility of O-H···π bonding.…”