Jump to main content
Jump to site search


Halogen bonding in 5-iodo-1-arylpyrazoles investigated in the solid state and predicted by solution 13C-NMR spectroscopy

Author affiliations

Abstract

X-ray crystallography revealed the presence of halogen bonding in the crystal supramolecular structure of three highly substituted 1-arylpyrazoles. However the compounds 1–3 present different halogen bonding motifs that feature C–I⋯N (1), C–I⋯O (2) and C–I⋯π (3) contacts respectively. The magnitudes of the σ-hole corresponding to the iodine atom in the 5-iodo-1-arylpyrazoles 1–3 were calculated by DFT methods and the importance of halogen bonding as a significant stabilizing force within the crystal lattice was evaluated. The halogen bonding of 1-aryl-5-iodopyrazoles with several Lewis bases (Et3N, pyridine, DABCO or DMSO) was investigated by 13C NMR spectroscopy in the solution phase to confirm the halogen bonding affinity of the iodine atom. The most suitable reporting atom for the formation of the halogen bond is C-5 of the pyrazole ring, which is directly bonded to the iodine atom. The C-5 atom is significantly deshielded by as much as 6–7 ppm upon interaction with the Lewis bases in solution revealing the strong halogen bonding character of the iodine atom attached to C-5 of the pyrazole ring.

Graphical abstract: Halogen bonding in 5-iodo-1-arylpyrazoles investigated in the solid state and predicted by solution 13C-NMR spectroscopy

Back to tab navigation

Supplementary files

Publication details

The article was received on 12 Aug 2019, accepted on 17 Oct 2019 and first published on 18 Oct 2019


Article type: Paper
DOI: 10.1039/C9CE01263J
CrystEngComm, 2019, Advance Article

  •   Request permissions

    Halogen bonding in 5-iodo-1-arylpyrazoles investigated in the solid state and predicted by solution 13C-NMR spectroscopy

    M. M. Popa, I. C. Man, C. Draghici, S. Shova, M. R. Caira, F. Dumitrascu and D. Dumitrescu, CrystEngComm, 2019, Advance Article , DOI: 10.1039/C9CE01263J

Search articles by author

Spotlight

Advertisements