Related Experiment Video
Updated: Aug 10, 2026

Modification and Functionalization of the Guanidine Group by Tailor-made Precursors
Published on: April 27, 2017
Anion-dependent dimerization of a guanidiniocarbonyl pyrrole cation in DMSO
1Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50939 Köln, Germany. carsten.schmuch@uni-koeln.de
Abstract:
With spherical counteranions such as chloride or hexafluorophosphate, the glycine-derived guanidiniocarbonyl pyrrole cation 1 self-assembles into discrete dimers in DMSO, as can be seen by NMR and ESI mass spectral analysis. According to concentration- and temperature-dependent NMR studies, the dimerization is endothermic and therefore entropy driven. Molecular modeling suggests that the dimers are held together by hydrogen bonding in combination with pi-pi interactions. In the presence of picrate anions, dimerization of cation 1 does not occur, probably due to the formation of pi-stacked ion pairs.
Related Concept Videos
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
Aldehydes and Ketones with Amines: Imine Formation Mechanism
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Anionic Chain-Growth Polymerization: Overview
Anionic Chain-Growth Polymerization: Mechanism
Cationic Chain-Growth Polymerization: Mechanism

