Herein,
we examine how the combination of multiple intermolecular
interactions influences the supramolecular assembly of dipyridinylmethyl
oxalamides and tetrafluorodiiodobenzenes into distinct well-defined
nanostructures. A series of 6 regioisomers were selected and crystallized
resulting in 11 cocrystals and 1 cocrystal solvate. Three halogen-
and hydrogen-bonded supramolecular macrocycles were observed, two
of which form large enough channels to accommodate disordered guest
molecules. In another case, packing of infinite chains formed columnar
channels, which were occupied with stacks of the halogenated coformers.
Molecular electrostatic potential surfaces were calculated to qualitatively
rank each binding site in order to make inferences about the expected
assembly patterns. Although the oxalamide oxygen was not always predicted
to be the best acceptor, self-association of this building block satisfies
two donors and two acceptors and was primarily observed. Further N···I
halogen-bonding interactions formed from pyridyl acceptors and halobenzene
donors. Simple electrostatic potential calculations prove to be practical
guidelines for predicting the outcome of multiple component crystallizations.
But when cooperative directing units, such as oxalamides are employed,
additional factors including the number and proximity of functional
groups as well as geometric constraints appear to be necessary.
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