Sequential Halogen Bonding with Ditopic Donors: σ-Hole Evolutions upon Halogen Bond Formation

摘要: The halogen bonding ability of ditopic bond donors can be assessed from the maximum value molecular surface electrostatic potential, called σ-hole, at two atoms. We show here that in N,N′-diodo-dimethylhydantoin (DIH), (XB) nitrogen-bound iodine atoms does not parallel calculated σ-hole amplitude. cocrystallization DIH with a series para-substituted pyridines, noted Py-R (R = pyrrolidinyl, NMe2, Me, H, CO2Me, CF3, CN), affords bis-adducts DIH·(Py-R)2 more electron-rich while mono-adducts DIH·(Py-R) are favored electron-poor pyridines CN). Analysis structural characteristics these mono- and bis-adducts, combined theoretical calculations, demonstrates formation first N–I···N′Py-R XB deeply modifies (and associated σ-hole) second uncoordinated atom. Under conditions, latter might associate through I···O to the...