Halogen and Chalcogen Bonding Between the Triphenylphosphine Chalcogenides (Ph3P=E; E=O, S, Se) and Iodofluorobenzenes

A series of cocrystals of Ph3P=E (E=O, S, Se) with organoiodines were studied to understand the roles of noncovalent interactions including chalcogen (ChB) and halogen (XB) bonding in their formation. The structure of the cocrystal of Ph3P=S and 1,2-diiodotetrafluorobezene was determined, which demonstrates a similar chalcogen...iodine XB pattern to the previously reported isomorphic Ph3P=Se structure. The cocrystalline structures resulting from the combination of 1,3-diiodotetrafluorobenzene (1,3-F4DIB), as well as iodopentafluorobenzene, with all three triphenylphosphine chalcogenides, were also determined. The (Ph3P=Se) . (1,3-F4DIB) cocrystal presents a rare example of a selenium...organoiodine ChB. The observed ChB and XB interactions have normalized distance parameters (R-XB) ranging from 0.80 to 0.98. The strength of the XB and ChB interactions were analyzed using natural bond orbital (NBO) theory, with calculated energies falling between 3.14 kcal/mol and 12.81 kcal/mol.

Automated summary

This study investigates the roles of chalcogen and halogen bonding in the formation of cocrystals of Ph3P=E (E=O, S, Se) with organoiodines. Different structures and interactions were observed among the chalcogenides and organoiodines, with some selenium...organoiodine ChB formations being rare examples. The strength of the interactions was analyzed using natural bond orbital (NBO) theory, with calculated energies falling between 3.14 kcal/mol and 12.81 kcal/mol.