Solid‐state multinuclear magnetic resonance and X‐ray crystallographic investigation of the phosphorus…iodine halogen bond in a bis(dicyclohexylphenylphosphine)(1,6‐diiodoperfluorohexane) cocrystal

• Published in: Acta crystallographica Section B, Structural science, crystal engineering and materials Structural science, crystal engineering and materials, 2022-06, Vol.78 (3-2), p.557-563
• Main Authors: Zheng, Dan Ni, Szell, Patrick M. J., Khiri, Safaa, Ovens, Jeffrey S., Bryce, David L.
• Format: Article
• Language: English
• Subjects: Chemical bonds; Chemical equilibrium; cocrystal; Crystal structure; crystallographic disorder; Crystallography; halogen bonding; Iodine; mechanochemistry; NMR; Nuclear magnetic resonance; Phosphorus; Resonance; solid‐state NMR
• ISSN: 2052-5206; 2052-5192; 2052-5206
• DOI: 10.1107/S2052520622004322

Halogen bonding to phosphorus atoms remains uncommon, with relatively few examples reported in the literature. Here, the preparation and investigation of the cocrystal bis(dicyclohexylphenylphosphine)(1,6‐diiodoperfluorohexane) by X‐ray crystallography and solid‐state multinuclear magnetic resonance spectroscopy is described. The crystal structure features two crystallographically unique C—I…P halogen bonds [dI…P = 3.090 (5) Å, 3.264 (5) Å] and crystallographic disorder of one of the 1,6‐diiodoperfluorohexane molecules. The first of these is the shortest and most linear I…P halogen bond reported to date. 13C, 19F, and 31P magic angle spinning solid‐state NMR spectra are reported. A 31P chemical shift change of −7.0 p.p.m. in the cocrystal relative to pure dicyclohexylphenylphosphine, consistent with halogen bond formation, is noted. This work establishes iodoperfluoroalkanes as viable halogen bond donors when paired with phosphorus acceptors, and also shows that dicyclohexylphenylphosphine can act as a practical halogen bond acceptor. The halogen‐bonded cocrystal bis(dicyclohexylphenylphosphine)(1,6‐diiodoperfluorohexane) is prepared mechanochemically and investigated by X‐ray crystallography and solid‐state NMR spectroscopy, revealing the presence of a rare C—I…P halogen bond.