Phosphoryl Halogen and Hydrogen Bonding Controls the Solid‐State Structures of Aryl Halide‐Containing Phosphonates

The reaction of the aryllithium derivative 2,6‐[P(O)(O‐ i ‐Pr) 2 ] 2 ‐4‐ t ‐Bu‐C 6 H 2 Li with iodine chloride, ICl, and elemental bromine, Br 2 , respectively, gave the aryl halides 2,6‐[P(O)(O‐ i ‐Pr) 2 ] 2 ‐4‐ t ‐Bu‐C 6 H 2 X ( 1 , X = I; 2 , X = Br, respectively). The aryl iodide 1 was characterized by 1 H, 13 C, 31 P NMR, and IR spectroscopy, and both 1 and the water solvate 2 ·H 2 O by single‐crystal X‐ray diffraction analysis. The structure of 1 in the solid state revealed weak inter‐ and intramolecular P =O···I–Ar electrostatic halogen bonding (HaB) interactions, resulting in 1 being a dimer in the solid state. In solution, however, it is a monomer. For the sake of comparison, the solid‐state structure of the aryl bromide derivative 2,6[P(O)(O‐ i ‐Pr) 2 ] 2 ‐4‐ t ‐Bu‐C 6 H 2 Br·H 2 O ( 2 ·H 2 O) is also reported, revealing a polymeric 2D structure as a result of P O···HOH···OP hydrogen bonds (HBs) and weak intermolecular P( i ‐Pr)O···BrAr HaB interactions. Natural bonding orbital (NBO) and quantum theory of atoms in molecule (QTAIM)/density functional theory (DFT) calculations helped elucidating the nature of the interactions.