Solid-state multinuclear maenetic resonance and X-ray crystallogrannic investigation of the phosphorus•••iodine halogen bond in a bis(dicyclohexymnenylphosphine)(1,6-diiodoperfluorohexane) cocrystal

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 center dot center dot center dot P halogen bonds [d(I)center dot center dot(P) = 3.090 (5) angstrom, 3.264 (5) angstrom] and crystallographic disorder of one of the 1,6-diiodoperfluorohexane molecules. The first of these is the shortest and most linear I center dot center dot center dot P halogen bond reported to date. C-13, F-19, and P-31 magic angle spinning solid-state NMR spectra are reported. A P-31 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.

Automated summary

This study describes the preparation and investigation of a cocrystal that forms halogen bonding with phosphorus atoms. The crystal structure reveals the shortest and most linear I···P halogen bond reported to date. Solid-state NMR spectra show a chemical shift change, indicating the formation of the halogen bond. This research demonstrates the viability of halogen bonding between iodoperfluoroalkanes and phosphorus acceptors, as well as the potential of dicyclohexylphenylphosphine as a halogen bond acceptor.