The role of secondary bonding on supramolecular assembly of coordination compounds: diversity of coordination modes and supramolecular structures

In this study, N-(2-halophenyl)-2-pyrazinecarboxamide ligands, L2-F, L2-Cl, L2-Br, and L2-I, carrying different halogen atoms in the phenyl ortho-position have been employed for the synthesis of twelve mercury(II) complexes. Many of the differences in the structural motifs of these complexes can be attributed to the different halide anions and also the different halogen substituents of the L2-X ligands. The effects of these parameters have been discussed with the help of geometrical analysis and calculations. This study reveals an undeniable contribution from the Hg center dot center dot center dot N-pyz secondary bonding interaction to the organization and stabilization of some of the crystal structures reported here.