Related Experiment Video
Updated: Jul 5, 2026
16:24
Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
Structural assignment of adenine aggregates in CDCl3.
Lars Biemann1, Thomas Häber, Daniela Maydt
1Institut für Physikalische Chemie, Heinrich-Heine Universität Düsseldorf, 40225 Düsseldorf, Germany.
The Journal of Chemical Physics
|May 27, 2008
Summary
This study examines how 9-substituted adenine derivatives self-associate in solution using infrared spectroscopy. Researchers identified distinct dimer structures for 9-ethyladenine, while N-methyl-9-ethyladenine showed a dominant single dimer isomer.
Area of Science:
- Supramolecular Chemistry
- Spectroscopy
- Computational Chemistry
Background:
- Adenine derivatives are fundamental in biological systems and exhibit self-association properties.
- Understanding self-association is crucial for designing molecules with specific functions.
Purpose of the Study:
- To investigate the self-association of 9-ethyladenine and N-methyl-9-ethyladenine in CDCl3.
- To determine the structures of adenine derivative aggregates using spectroscopic and computational methods.
Main Methods:
- Infrared (IR) spectroscopy was employed to analyze the self-association of adenine derivatives.
- A deconvolution method was used to determine extinction coefficients of monomers and dimers.
- Quantum chemical calculations were performed to assign dimer structures.
Main Results:
- Infrared spectra of 9-ethyladenine and N-methyl-9-ethyladenine aggregates were obtained.
- Wavelength-dependent extinction coefficients for monomers and dimers were calculated.
- Two coexisting dimer structures were identified for 9-ethyladenine, while N-methyl-9-ethyladenine exhibited a single dominant dimer isomer.
Conclusions:
- The study successfully characterized the self-association behavior of specific adenine derivatives.
- Spectroscopic and computational data provided insights into the structural diversity of adenine dimers.
- Findings contribute to understanding molecular interactions in adenine-based systems.
Related Concept Videos
01:19Structure of Amines
The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’ carbon–carbon bond (154 pm). These aspects are illustrated in Figure...
01:17Nomenclature of Primary Amines
Primary, secondary, and tertiary amines are compounds consisting of one, two, and three alkyl groups connected to the amino group (–NH2), respectively. As depicted in Figure 1, the common name of the primary amines is obtained by adding the suffix -amine to the alkyl substituent attached to the amino group as the corresponding alkylamine.
01:16Structure of Conjugated Dienes
Introduction
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
01:16Adrenergic Agonists: Chemistry and Structure-Activity Relationship
Adrenergic agonists' structure-activity relationship (SAR) determines their selectivity and efficacy. These agonists comprise a phenylethylamine moiety with an aromatic ring and an ethylamine side chain.
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
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.
01:18π 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...