Co-crystallization of sym-triiodo-trifluorobenzene with bipyridyl donors: Consistent formation of two instead of anticipated three N⋯I halogen bonds

André C.B. Lucassen, Amir Karton, Gregory Leitus, Linda J.W. Shimon, Jan M.L. Martin, Milko E. Van Der Boom

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The potential triple-halogen-bond acceptor, sym-triiodo-trifluorobenzene IFB (1), has been co-crystallized with a series of bipyridyl derivatives (2-4) to gain insight to the factors controlling formation of multiple halogen bonds with a single aromatic system. Co-crystals 5-7 were obtained that consistently contained two N⋯I halogen bonds. The reluctance to the formation of a supramolecular assembly having a third N⋯I halogen bond does not depend on the size of the bispyridine donor systems (2-4). Apparently, there are limitations to the number of halogen bonds that can be formed with a single aromatic halogen donor. The solid-state structure of co-crystal (5) contains short I⋯F contacts of 2.96 and 3.05 A. DFT calculations were performed at the PBE0/(apc1-aSDBDZ)//PBEO/(pc1-SDBDZ) level of theory to investigate the nature of the interaction between the pyridine nitrogen and IFB (1). These calculations reveal a weakening of N⋯I interactions as more pyridine moieties coordinate to the IFB (1), which might be a contributing factor to the consistent formation of two rather than three N⋯I halogen bonds.

Original languageEnglish
Pages (from-to)386-392
Number of pages7
JournalCrystal Growth and Design
Issue number2
Publication statusPublished - Feb 1 2007


ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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