Weak yet Decisive: Molecular Halogen Bond and Competing Weak Interactions of Iodobenzene and Quinuclidine

Journal of the American Chemical Society, vol. 143, pp. 4133–4137

Abstract

The halogen bonded adduct between the commonly used constituents quinuclidine and iodobenzene is based on a single weak nitrogen-iodine contact, and the isolation of this adduct was initially unexpected. Iodobenzene does not contain any electron-withdrawing group and therefore represents an unconventional halogen bond donor. Based on excellent diffraction data of high resolution, an electron density study was successfully accomplished and confirmed one of the longest N···I molecular halogen bonds with a distance of 2.9301(4) Å. The topological analysis identified the XB as a directional but weak σ hole interaction and revealed secondary contacts between peripheral regions of opposite charge. These additional contacts and their competition with a nitrogen-based interaction were confirmed by NOESY experiments in solution. Integration enabled us to determine the relative NOE ratios and provided insight regarding the existing interactions.

Authors 6

1. Felix Otte

   TU Dortmund University

   Affiliation as printed

   TU Dortmund University, Inorganic Chemistry, Otto-Hahn-Str. 6, D-44227, Dortmund, Germany

2. Johannes Kleinheider

   TU Dortmund University

   Affiliation as printed

   TU Dortmund University, Inorganic Chemistry, Otto-Hahn-Str. 6, D-44227, Dortmund, Germany

3. Wolf Hiller

   TU Dortmund University

   Affiliation as printed

   TU Dortmund University, Faculty of Chemistry and Chemical Biology, Otto-Hahn-Str. 6, D-44227, Dortmund, Germany

   TU Dortmund University, Inorganic Chemistry, Otto-Hahn-Str. 6, D-44227, Dortmund, Germany

4. Ruimin Wang Aachen

   Shanxi University · RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Inorganic Chemistry, Landoltweg 1, D-52056, Aachen, Germany

   Shanxi University, Institute of Molecular Science, Wucheng Road 92, 030006, Taiyuan, P. R. China

5. Ulli Englert corresponding Aachen

   Shanxi University · RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Inorganic Chemistry, Landoltweg 1, D-52056, Aachen, Germany

   Shanxi University, Institute of Molecular Science, Wucheng Road 92, 030006, Taiyuan, P. R. China

6. Carsten Strohmann corresponding

   TU Dortmund University

   Affiliation as printed

   TU Dortmund University, Inorganic Chemistry, Otto-Hahn-Str. 6, D-44227, Dortmund, Germany