The Anisole-ammonia complex: marks of the intermolecular interaction

We report an experimental study, supported by classical and quantum calculations, of the anisole-ammonia jet cooled complex. The origin band of the S1 <- S-0 electronic transition is red shifted with respect to the corresponding band for the bare anisole molecule. From the simulation of the origin band rotational contour and the results of quantum mechanical calculations, we have been able to determine the non-planar structure of the complex. The ammonia molecule is bonded to anisole via two hydrogen bonds: one in which the nitrogen lone pair interacts with the hydrogen atoms of the methoxy group; the other involving the ammonia hydrogen atoms and the pi-electron density of the aromatic ring.