Related Experiment Video
Updated: Jun 1, 2026
09:04
A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products
Published on: September 9, 2016
Guanidinium 4-amino-benzoate
P S Pereira Silva1, M Ramos Silva, J A Paixão
1CEMDRX, Physics Department, University of Coimbra, P-3004-516 Coimbra, Portugal.
Summary
This study details the crystal structure of a guanidinium 4-aminobenzoate compound. The analysis reveals layered structures formed by hydrogen bonds, similar to guanidinium benzoate.
Area of Science:
- Crystallography
- Materials Science
- Chemical Physics
Background:
- Guanidinium salts are widely studied for their diverse structural and physical properties.
- Benzoate derivatives offer tunable electronic and structural characteristics.
- Understanding the interplay between organic anions and inorganic cations is crucial for materials design.
Purpose of the Study:
- To elucidate the crystal structure of the guanidinium 4-aminobenzoate salt.
- To investigate the intermolecular interactions, specifically hydrogen bonding, within the crystal lattice.
- To compare the observed structure with related compounds like guanidinium benzoate.
Main Methods:
- Single-crystal X-ray diffraction was employed to determine the three-dimensional structure.
- Analysis of bond lengths, bond angles, and intermolecular distances.
- Identification and analysis of hydrogen bonding networks.
Main Results:
- The crystal structure features guanidinium cations and 4-aminobenzoate anions situated on crystallographic mirror planes.
- The 4-aminobenzoate anion exhibits a near-planar conformation with charge delocalization in the carboxylate group.
- N-H⋯O hydrogen bonds link the ions into layered structures propagating in the bc plane.
Conclusions:
- The crystal packing is dominated by N-H⋯O hydrogen bonds, forming extended layers.
- The structural arrangement is highly analogous to that of guanidinium benzoate, suggesting similar packing motifs.
- The delocalized charge in the carboxylate group influences the overall crystal structure and stability.
Related Concept Videos
01:19Diazonium Group Substitution: –OH and –H
Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.
01:26Physical Properties of Amines
Amines with low molecular weight are usually gaseous at room temperature, while those with high molecular weight are liquid or solids in nature. Usually, low molecular weight amines have a rotten fish-like smell. Diamines typically have a pungent smell. For instance, cadaverine and putrescine, depicted in Figure 1, are two molecules responsible for decaying tissue.