Computational Study of Intra and Intermolecular Interactions in Hexamethylenetetramine Complexes With Halogens and Diatomic Interhalogens

ABSTRACT Structures, energetics and chemical bonding in molecular and ionic complexes of diatomic halogens and interhalogens XX′ (X, X′ = Cl, Br, I) with hexamethylenetetramine (HMTA) were computationally studied at the M06‐2X/def2‐TZVP level of theory. The stability of the molecular HMTA· n XX′ complexes decreases with increasing n : 1 > 2 > 3 > 4 for all XX′. The bonding between HMTA and XX′ in molecular complexes is best described as donor–acceptor interaction. Complexes with interhalogens, in particular with ICl, feature stronger donor–acceptor interactions and their dissociation is predicted to be endergonic at room temperature. In contrast, the intermolecular interactions are predominantly van der Waals type or electrostatic. Intermolecular N…X interactions are too weak for building coordination polymers based on HMTA and molecular halogens.