From Coordination Polyhedra to Molecular Environment and Back – Interplay between Coordinate and Hydrogen Bonds in Two Polymorphs of a Cobalt Complex



Two crystalline modifications of a cobalt(II) benzoate complex containing substituted pyrazole ligands are investigated. The polymorphs are characterized by different intermolecular bonding as well as by different metal-atom environments. A thorough analysis of the chemical bonding patterns by means of Bader's “Atoms in Molecules” theory reveals the significant role of N–H···O hydrogen bonds in charge transfer within the molecule and in stabilization of unfavorable [4+1] cobalt polyhedra. Specifically, an estimation of the interaction energies according to an Espinosa correlation scheme shows the significant contribution of H bonds to the stabilization energy of the molecular conformations.