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

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 center dot center dot center dot O, I center dot center dot center dot N, and I center dot center dot center dot I halogen bonding interactions. Besides this, the overall supramolecular architecture of the coordination complexes is modulated by the N-H center dot center dot center dot O, N-H center dot center dot center dot Br, and C-H center dot center dot center dot O hydrogen bonds formed by the carboxamide group. The combination of both, halogen and hydrogen bonds, allows very different coordination networks to be designed.