The structures of three iodochalcones, functionalized with fluorine or a nitro group, have been investigated to explore the impact of different molecular electrostatic distributions on the halogen bonding within each crystal structure. The strongly withdrawing nitro group presented a switch of the halogen bond from a lateral to a linear motif. Surprisingly, this appears to be influenced by a net positive shift in charge distribution around the lateral edges of the σ-hole, making the lateral I...I bonding motif less preferable. A channel of amphoteric I...I type II halogen bonds is observed for a chalcone molecule, which was not previously reported in chalcones, alongside an example of the common synthon involving extended linear chains of I...O2N donor-acceptor halogen bonds. This work shows that halogenated chalcones may be an interesting target for developing halogen bonding as a significant tool within crystal engineering, a thus far underexplored area for this common structural motif.
|Number of pages||10|
|Journal||Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials|
|Issue number||Pt 3|
|Publication status||Published - 1 Jun 2021|
Bibliographical noteFunding Information:
The following funding is acknowledged: Engineering and Physical Sciences Research Council (grant Nos. EP/L016648/1 and EP/L015544/1); European Union Horizon (grant agreement No. 73689).
SRH, VH, JP and CH would like to acknowledge funding from the Engineering and Physical Sciences Research Council UK with support from the Bristol Centre for Functional Nano-materials, the Centre for Doctoral Training In Condensed Matter Physics and the MagnaPharm project, which has received funding from the European Union’s Horizon 2020 Research and Innovation programme. Gonzaga University coauthors thank S. Economu, B. Hendricks, J. Hazen, J. Grisaffi, C. Held, E. Harmston, C. McCormick, K. Okubo and M. Ortiz for their assistance, as well as the Howard Hughes Medical Institute through its Undergraduate Science Education Program for supporting equipment acquisition. Support also
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- halogen bonding
- crystal engineering
- crystal structure