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Updated: Jun 1, 2026
04:51
Synthesis of Triazole and Tetrazole-Functionalized Zr-Based Metal-Organic Frameworks Through Post-Synthetic Ligand Exchange
Published on: June 23, 2023
Bis(2-aminopyridinium) tetra-chloridozincate(II)
1Ordered Matter Science Research Center, Southeast University, Nanjing 210096, People's Republic of China.
Summary
This study characterizes the crystal structure of a new zinc chloride compound. The structure reveals protonated pyridine nitrogen atoms and distorted tetrahedral zinc chloride anions, stabilized by hydrogen bonds and pi-pi interactions.
Area of Science:
- Inorganic Chemistry
- Crystallography
- Materials Science
Background:
- The synthesis and structural characterization of novel coordination compounds are crucial for understanding chemical bonding and developing new materials.
- Zinc chloride complexes are of interest due to their diverse structural motifs and potential applications.
Purpose of the Study:
- To elucidate the crystal structure of the compound bis(pyridinium) tetrachlorozincate, (C(5)H(7)N(2))(2)[ZnCl(4)].
- To investigate the intermolecular interactions governing the crystal packing.
Main Methods:
- Single-crystal X-ray diffraction was employed to determine the three-dimensional crystal structure.
- Analysis of bond lengths, bond angles, and intermolecular distances (hydrogen bonds, pi-pi interactions) was performed.
Main Results:
- The crystal structure consists of protonated pyridine cations (pyridinium) and tetrachlorozincate ([ZnCl(4)](2-)) anions.
- The [ZnCl(4)](2-) anions exhibit a slightly distorted tetrahedral geometry.
- Weak N-H⋯Cl hydrogen bonds and π-π interactions (centroid-centroid distance of 4.2758 Å) were identified as key stabilizing forces in the crystal lattice, organizing the molecules into layers.
Conclusions:
- The compound (C(5)H(7)N(2))(2)[ZnCl(4)] has been successfully synthesized and structurally characterized.
- The crystal packing is significantly influenced by a combination of hydrogen bonding and π-π stacking interactions.
- This structural insight contributes to the broader understanding of supramolecular assembly in metal-organic compounds.
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.
01:371° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
01:261° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
01:25Basicity of Heterocyclic Aromatic Amines
Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.
01:20Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Arenediazonium substitution reactions occur when the diazonium group is substituted by various functional groups such as halides, hydroxyl, nitrile, etc. For instance, arenediazonium salts react with copper(I) salts of chloride, bromide, or cyanide to form corresponding aryl chlorides, bromides, and nitriles. These reactions are named Sandmeyer reactions. Although the mechanism of this reaction is complicated, as illustrated in Figure 1, they are believed to progress via an aryl copper...