Relative Stability and Spectroscopic Regularity of C80O Based on C80(D5d)
Acta Chimica Slovenica
|September 25, 2013
Summary
Density Functional Theory (DFT) identified the most stable C80O isomer, 23,24-C80O, featuring an annulene-like structure. This isomer exhibits altered vibrational frequencies, NMR signals, and reduced anti-aromaticity compared to C80(D5d).
Area of Science:
- Computational chemistry
- Theoretical physics
- Materials science
Background:
- Fullerenes are allotropes of carbon with unique electronic properties.
- C80O, an oxygen-doped fullerene, presents diverse isomeric possibilities.
- Understanding fullerene isomer stability is crucial for predicting their behavior.
Purpose of the Study:
- To investigate the relative stabilities of C80O isomers.
- To characterize the structural and electronic properties of the most stable C80O isomer.
- To compare the properties of C80O with the parent C80 fullerene.
Main Methods:
- Density Functional Theory (DFT) calculations at the B3LYP/6-31G(d) level.
- Geometry optimization to determine stable structures.
- Infrared (IR) and Nuclear Magnetic Resonance (NMR) spectroscopy simulations.
- Nucleus-independent chemical shift (NICS) calculations to assess aromaticity.
Main Results:
- The 23,24-C80O isomer was predicted as the most stable, forming an annulene-like structure.
- IR spectra showed blue-shifted C=C bond stretching frequencies for C80O compared to C80(D5d).
- NMR spectra indicated upfield shifts for bridged carbon atoms in C80O.
- NICS values revealed decreased anti-aromaticity in C80O rings, with one hexagon showing aromaticity.
Conclusions:
- The 23,24-C80O isomer is the most stable configuration.
- Oxygen doping significantly influences the electronic and structural properties of C80.
- C80O isomers exhibit modified aromaticity compared to the parent C80 fullerene.
More Related Videos
14:55Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
11:27X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
Related Concept Videos
01:59Relative Stabilities of Alkenes
The relative stability of alkenes can be determined by comparing their heats of hydrogenation. The lower heat of hydrogenation indicates the more stable alkene. The three main factors determining the relative stability of alkenes are i) the number of substituents attached to the double-bond carbon atoms, ii) hyperconjugation, and iii) the stereochemistry of the double bond.
02:29Conformations of Cycloalkanes
Adolf von Baeyer attempted to explain the instabilities of small and large cycloalkane rings using the concept of angle strain — the strain caused by the deviation of bond angles from the ideal 109.5° tetrahedral value for sp3 hybridized carbons. However, while cyclopropane and cyclobutane are strained, as expected from their highly compressed bond angles, cyclopentane is more strained than predicted, and cyclohexane is virtually strain-free. Hence, Baeyer’s theory that was based on the...
02:30Stability of Substituted Cyclohexanes
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
02:02Chair Conformation of Cyclohexane
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
01:28Stability of Conjugated Dienes
Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
02:11Conformations of Cyclohexane
Cyclohexane does not exist in a planar form due to the high angle and torsional strain it would experience in the planar structure. Instead, it adopts non-planar chair and boat conformations.
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...