Establishing Halogen-Bond Preferences in Molecules with Multiple Acceptor Sites

Amila M Abeysekera; Boris B Averkiev; Abhijeet S Sinha; Pierre Le Magueres; Christer B Aakeröy

doi:10.1002/cplu.202100102

Establishing Halogen-Bond Preferences in Molecules with Multiple Acceptor Sites

Chempluschem. 2021 May 4;86(8):1049-1057. doi: 10.1002/cplu.202100102. Online ahead of print.

Authors

Amila M Abeysekera¹, Boris B Averkiev¹, Abhijeet S Sinha¹, Pierre Le Magueres², Christer B Aakeröy¹

Affiliations

¹ Department of Chemistry, Kansas State University, 213 CBC Building, 1212 Mid-Campus Dr North, Manhattan, KS 66506-0401, USA.
² Rigaku Americas Corporation, 9009 New Trails Drive, The Woodlands, TX 77381, USA.

PMID: 34008343
DOI: 10.1002/cplu.202100102

Abstract

The interplay between hydrogen bonds (HBs) and halogen bonds (XBs), has been addressed by co-crystallizing two halogen bond donors, 1,4-diiodotetrafluorbenzene(DITFB) and 1,3,5-trifluoro-2,4,6-triiodobenzene(TITFB) with four series of targets; N-(pyridin-2-yl)benzamide (Bz-X), N-(pyridin-2-yl)picolinamides (2Pyr-X), N-(pyridin-2-yl)nicotinamides (3Pyr-X), N-(pyridin-2-yl)isonicotinamides (4Pyr-X); X=H/Cl/Br/I. The structural outcomes were compared with interactions in the targets themselves. 13 co-crystals were analysed by single-crystal X-ray diffraction (SCXRD). In all three co-crystals from the 2Pyr series, the intramolecular HB remained intact while the XB donors engaged with the N(pyr) or O=C sites. In the ten co-crystals from the other three series, the intermolecular HBs present in the individual targets were disrupted in 9/10 cases. Overall, the acceptor sites selected by the halogen-bond donors in these targets were distributed as follows; N(pyr)=81 %, O=C (15 %) or π (4 %).

Keywords: co-crystals; crystal engineering; halogen bonding; hydrogen bonding; supramolecular chemistry.

Abstract

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