Formation of Planar π-Conjugated Sheets in Cocrystals of Bis(iodoethynyl)pyridines and Bipyrimidylalkynes: Cooperative C–H···N Hydrogen Bonds and sp-C–I···N Halogen Bonds

Abstract

The cocrystallization of the ditopic halogen bond donors 2,5-, 2,6-, 3,5-bis(iodoethynyl)pyridines with the dipyrimidyls 1,2-bis(5-pyrimidyl)ethyne and 1,4-bis(5-pyrimidyl)butadiyne is explored. The cocrystal components have complementary shapes and functional groups so that the noncovalent C–I···N halogen bonding and C–H···N hydrogen bonding interactions are complementary resulting in 1:1 cocrystals with the ditopic halogen bond accepting bipyrimidyls. The cocrystals feature π-stacked planar sheets of alternating bis(iodoalkynes) and bipyrimidyls held together in one direction by I···N halogen bonds and in the roughly orthogonal direction by pyridine–pyridine and pyrimidine–pyrimidine C–H···N hydrogen bonds.

Cooperative C–H···N hydrogen bonding and sp-C–I···N halogen bonding in a series of bis(iodoalkynyl)pyridines and bipyrimidines results in the formation of planar conjugated sheets within the cocrystals.