Azido-mediated intermolecular interactions of transition metal complexes

The coordinated azido ligand has a variety of ways to establish intermolecular contacts whose nature is computationally analysed in this work on dimers of the [N3-Hg(CF3)] complex with different interactions involving only NMIDLINE HORIZONTAL ELLIPSISN contacts, or with an additional HgMIDLINE HORIZONTAL ELLIPSISN contact. The applied tools include the molecular electrostatic map of the monomer, an energy decomposition analysis (EDA), a topological AIM analysis of the electron density and the study of NCI (non-covalent interactions) isosurfaces. The interactions between two azido ligands are found to be weakly stabilizing (by 0.2 to 2.7 kcal mol-1), topology-dependent and require dispersion forces to complement orbital and electrostatic stabilization. Those interactions are supplemented by the formation of simultaneous HgMIDLINE HORIZONTAL ELLIPSISN secondary interactions by about -1 kcal mol-1, and by the ability of the monomer to simultaneously interact with several neighbours in the crystal structure. By means of a comprehensive structural and computational analysis, we explore herein the rich supramolecular chemistry between azido ligands in transition metal complexes.