Structure of Amido-Pyridinium Betaines: Persistent Intermolecular C-H•••N Hydrogen Bonding in Solution

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A hydrogen bond of the type C-H⋯X (X=O or N) is known to influence the structure and function of chemical and biological systems in solution. C-H⋯O hydrogen bonding in solution has been extensively studied, both experimentally and computationally, whereas the equivalent thermodynamic parameters have not been enumerated experimentally for C-H⋯N hydrogen bonds. This is, in part, due to the lack of systems that exhibit persistent C-H⋯N hydrogen bonds in solution. Herein, a class of molecule based on a biologically active norharman motif that exhibits unsupported intermolecular C-H⋯N hydrogen bonds in solution has been described. A pairwise interaction leads to dimerisation to give bond strengths of about 7 kJ mol-1 per hydrogen bond, which is similar to chemically and biologically relevant C-H⋯O hydrogen bonding. The experimental data is supported by computational work, which provides additional insight into the hydrogen bonding by consideration of electrostatic and orbital interactions and allowed a comparison between calculated and extrapolated NMR chemical shifts.
Original languageEnglish
Pages (from-to)3414-3421
Number of pages8
JournalChemistry : A European Journal
Issue number10
Early online date28 Jan 2016
Publication statusPublished - 1 Mar 2016

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. © 2016, Wiley-VCH. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details


  • aggregation
  • betaines
  • bond energy
  • hydrogen bonds
  • nitrogen heterocycles

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