An unusual werner type clathrate of Mn(II) benzoate involving energetically significant weak C-H•••C contacts: A combined experimental and theoretical study

A new Werner type manganese(II) clatharate [Mn(Bz)(2)(H2O)4]center dot(4-CNpy)2H(2)O (1), where Bz = benzoate and 4-CNpy = 4-cyanopyridine, has been synthesized at room temperature and characterized by X-ray crystal structure analysis, FT-IR, electronic spectrum and TGA. The crystal structure of cocrystal hydrate of I involves a discrete host monomer with enclathrated water and 4-CNpy molecules. Crystallographic studies on the compound 1 reveal that enclathration of guest water molecules in the Mn(II) host units results in a supramolecular tetramer in the crystal structure of I involving weak C-H center dot center dot center dot C contacts. The geometry of the supramolecular host tetramer with the guest 4-CNpy molecules has been fully optimized using the crystallographic coordinates and the computational results suggest that the observed C-H center dot center dot center dot C interactions are energetically quite significant. It is observed that both electrostatics as well as dispersion interactions are the most dominant contributors towards the stabilization of the C-H center dot center dot center dot C interaction. (C) 2018 Elsevier B.V. All rights reserved.