Jump to main content
Jump to site search


Laser desorption single-conformation UV and IR spectroscopy of the sulfonamide drug sulfanilamide, the sulfanilamide-water complex, and the sulfanilamide dimer

Abstract

We have studied the conformational preferences of the sulfonamide drug sulfanilamide, its dimer, and its monohydrated complex through laser desorption single-conformation UV and IR spectroscopy in a molecular beam. Based on potential energy curves for the inversion of the anilinic and the sulfonamide NH2 groups calculated at DFT level, we suggest that the zero-point level wave function of the sulfanilamide monomer is appreciably delocalized over all four conformer wells. The sulfanilamide dimer, and the monohydrated complex each exhibit a single isomer in the molecular beam. The isomeric structures of the sulfanilamide dimer and the monohydrated sulfanilamide complex were assigned based on their conformer-specific IR spectra in the NH and OH stretch region. Quantum Theory of Atoms in Molecules (QTAIM) analysis of the calculated electron density in the water complex suggests that the water molecule is bound side-on in a hydrogen bonding pocket, donating one O-H···O=S hydrogen bond and accepting two hydrogen bonds, a NH···O and a CH···O hydrogen bond. QTAIM analysis of the dimer electron density suggests that the Ci symmetry dimer structure exhibits two dominating N-H···O=S hydrogen bonds, and three weaker types of interactions: two CH···O bonds, two CH···N bonds, and a chalcogen O···O interaction. Most interestingly, the molecular beam dimer structure closely resembles the R22 dimer unit –the dimer unit with the greatest interaction energy– of the α, γ, and δ crystal polymorphs. Interacting Quantum Atoms analysis provides evidence that the total intermolecular interaction in the dimer is dominated by the short-range exchange-correlation contribution.

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 07 Mar 2017, accepted on 18 May 2017 and first published on 18 May 2017


Article type: Paper
DOI: 10.1039/C7CP01464C
Citation: Phys. Chem. Chem. Phys., 2017, Accepted Manuscript
  •   Request permissions

    Laser desorption single-conformation UV and IR spectroscopy of the sulfonamide drug sulfanilamide, the sulfanilamide-water complex, and the sulfanilamide dimer

    T. Uhlemann, S. Seidel and C. W. Mueller, Phys. Chem. Chem. Phys., 2017, Accepted Manuscript , DOI: 10.1039/C7CP01464C

Search articles by author