IR, Raman and SERS spectra of propantheline bromide

The two known propantheline bromide polymorphs (form I and form II) were studied and characterized by a multianalytical approach. In the present work, the identification of propantheline bromide polymorphic forms through vibrational IR spectroscopies are presented and for the first time Raman microscopy and hot stage Raman microscopy (HSRM) studies are reported. Finally, quantum mechanical calculations were performed. For assisting the assignment of the experimental picks, the two IR spectra of the most and least stable representatives of a set of 56 conformers are calculated and studied.DSC thermograms data, are also reported. The surface enhanced Raman scattering (SERS) spectrum was also recorded in a silver colloid; it could be inferred that propantheline bromide is adsorbed on silver colloid through the oxygen atom with the molecular plane perpendicular to the metal surface.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Characterization of I and II propantheline bromide polymorphic forms. ► FT-IR, Raman and hot stage Raman microscopy studies and their vibrations assignments. ► DSC thermograms and X-ray powder diffraction data. ► SERS spectrum in a silver colloid: the drug is adsorbed through the oxygen atom. ► Quantum mechanical calculations of the most and least stable conformers.