The combination of halogen and hydrogen bonding: a versatile tool in coordination chemistry

Abstract

4-Iodo-N-(4-pyridyl)benzamide (INPBA) and four derived coordination complexes were synthesized in order to explore the combination of halogen and hydrogen bonding interactions in coordination chemistry. An electron-withdrawing carbonyl group attached to the aromatic ring bearing an iodine atom has been introduced to increase its halogen bonding ability. Single crystal X-ray diffraction analyses of INPBA, [Ag(INPBA)₂]NO₃ (1), [ZnBr₂(INPBA)₂] (2), [Zn(OCOPh)₂(INPBA)₂] (3) and [HgI₂(INPBA)]_n (4) show the versatility of the INPBA building block yielding a variety of different interesting structures. Iodine atom arrangement plays a key role by reinforcing and extending crystalline structures into diverse 3D supramolecular networks via I⋯O, I⋯N, and I⋯I halogen bonding interactions. Besides this, the overall supramolecular architecture of the coordination complexes is modulated by the N–H⋯O, N–H⋯Br, and C–H⋯O hydrogen bonds formed by the carboxamide group. The combination of both, halogen and hydrogen bonds, allows very different coordination networks to be designed.