Estimation of the barrier to rotation of benzene in the (η6-C6H6)2Cr crystal via topological analysis of the electron density distribution function

The high-resolution X-ray diffraction analysis of the electron density distribution and plane-wave density functional theory has been applied to estimate the lattice energy and barrier to rotation of a benzene ring in the crystal of (eta(6)-C6H6)(2)Cr. Experimental data made it possible to perform analysis of the metal-(pi-ligand) bond and estimate the nature and energy of weak H center dot center dot center dot H and H center dot center dot center dot C intermolecular interactions in the crystal. Summation of the intermolecular H center dot center dot center dot H and H center dot center dot center dot C interaction energies makes it possible to reproduce the experimental sublimation enthalpy value with high accuracy.