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Updated: May 5, 2026

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Mixed cocrystal approach influences the yield for a [2+2] cycloaddition reaction within a halogen-bonded organic
Nicole M Shapiro1, Mark D Govero1, Eric Bosch2
1Department of Natural Science and Mathematics, Webster University, St Louis, Missouri 63119, USA.
Abstract:
The synthesis, crystal structure, and [2+2] cycloaddition photoreactivity of a halogen-bonded mixed cocrystal is reported. The cocrystal solid solution contains two isosteric donors, namely, 1,4-diiodoperchlorobenzene (C6I2Cl4) and iodoperchlorobenzene (C6ICl5), along with trans-1,2-bis(pyridin-4-yl)ethylene (BPE, C12H10N2) which behaves as a ditopic reactant molecule. The mixed cocrystal, namely, (C6I2Cl4)0.75·(C6ICl5)0.25·(BPE), is achieved since both halogen-bond donors are similar in shape and are interchangeable at equivalent crystallographic positions. The combination of I...N and Cl...N halogen bonds generates one-dimensional chains that engage in homogeneous π-stacks, thereby positioning a pair of reactant molecules in a suitable location to photoreact. Notably, the overall yield for the solid-state photoreaction is influenced by the initial molar ratio of the isosteric halogen-bond donors within the mixed cocrystal.
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