Related Experiment Video
Updated: Jul 7, 2026
16:11
Thermochemical Studies of Ni(II) and Zn(II) Ternary Complexes Using Ion Mobility-Mass Spectrometry
Published on: June 8, 2022
Binding energies and dissociation pathways in the aniline-Ar2 cation complex
1Department of Chemistry, Wesleyan University, Middletown, Connecticut 06459, USA.
The Journal of Chemical Physics
|February 20, 2008
Summary
Mass analyzed threshold ionization spectroscopy measured the binding energy of cationic aniline-argon (An(+)-Ar) and aniline-argon(2) (An(+)-Ar(2)) complexes. A more stable hydrogen-bonded configuration was observed for An(+)-Ar(2).
Area of Science:
- Physical Chemistry
- Spectroscopy
- Computational Chemistry
Background:
- Aniline-argon complexes are studied to understand non-covalent interactions.
- Previous studies suggested different binding configurations.
Purpose of the Study:
- To measure the binding energies of cationic aniline-Ar and aniline-Ar(2) complexes.
- To investigate the structural configurations and stability of these complexes.
Main Methods:
- Mass analyzed threshold ionization spectroscopy was employed.
- Photoexcitation of neutral complexes created the cations.
- Binding energies were determined through spectroscopic measurements.
Main Results:
- The binding energy for the pi-bound An(+)-Ar complex was determined to be 495±15 cm(-1).
- A lower energy dissociation product for An(+)-Ar(2) was assigned to a hydrogen-bonded configuration.
- The dissociation energy for the hydrogen-bonded An(+)-Ar(2) complex was found to be 640±20 cm(-1).
Conclusions:
- The study confirms the existence of a more stable hydrogen-bonded conformer in aniline-argon complexes.
- Experimental findings are consistent with recent infrared spectroscopy results.
- Computational calculations accurately reproduced the pi-bound configuration but underestimated the stability of the hydrogen-bonded species.
More Related Videos
Related Concept Videos
01:18Basicity of Aromatic Amines
The basicity of aromatic amines is much weaker than that of aliphatic amines due to the involvement of the lone pair of electrons over the N atom in resonance with the aryl rings. Generally, the electron-donating ability of any substituents on the aryl ring of aromatic amines increases the basicity of the amine by increasing electron density, and hence the availability of lone pair on the nitrogen. On the other hand, electron-withdrawing functional groups on the aryl ring of amines decrease the...
01:18Aromatic Hydrocarbon Anions: Structural Overview
Neutral hydrocarbons like cyclopentadiene with an odd number of carbon atoms and one intervening CH2 group in the ring are not aromatic. Cyclopentadiene with 4 π electrons does not satisfy the 4n + 2 π electron rule. Additionally, the intervening CH2 group is sp3 hybridized and lacks a vacant p orbital, thereby interrupting the overlap of p orbitals in a continuous manner and preventing the delocalization of π electrons throughout the ring.
Due to the absence of continuous overlap of p...
Due to the absence of continuous overlap of p...
01:18π Molecular Orbitals of the Allyl Cation and Anion
An allyl group is a three-carbon conjugated system where the sp³-hybridized allylic carbon is bonded to a CH=CH2 group via a single bond. Allyl anions can be obtained by treating propene with a strong base that can deprotonate methyl groups. Allyl cations are formed as intermediates during substitution reactions involving allylic halides. In both cases, the hybridization of the allylic carbon changes from sp3 to sp2, giving rise to a carbon chain with three sp2-hybridized carbons, each with an...
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.
01:11Aryldiazonium 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.
01:14Aldehydes and Ketones with Amines: Enamine Formation Mechanism
Enamine formation involves the addition of carbonyl compounds to a secondary amine through a series of reactions. The mechanism begins with the generation of carbinolamine, a nucleophilic attack followed by several proton transfer reactions. The hydroxyl group of the carbinolamine is converted into water to make a better leaving group that can push the reaction forward by eliminating a water molecule. In enamine formation, the last step involves the abstraction of a proton from the α carbon to...