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Reinterpretation of Dynamic Vibrational Spectroscopy to Determine the Molecular Structure and Dynamics of Ferrocene
- Source :
- Chemistry - A European Journal. 22:18019-18026
- Publication Year :
- 2016
- Publisher :
- Wiley, 2016.
-
Abstract
- Molecular distortion of dynamic molecules gives a clear signature in the vibrational spectra, which can be modeled to give estimates of the energy barrier and the sensitivity of the frequencies of the vibrational modes to the reaction coordinate. The reaction coordinate method (RCM) utilizes ab initio-calculated spectra of the molecule in its ground and transition states together with their relative energies to predict the temperature dependence of the vibrational spectra. DFT-calculated spectra of the eclipsed (D5h ) and staggered (D5d ) forms of ferrocene (Fc), and its deuterated analogue, within RCM explain the IR spectra of Fc in gas (350 K), solution (300 K), solid solution (7-300 K), and solid (7-300 K) states. In each case the D5h rotamer is lowest in energy but with the barrier to interconversion between rotamers higher for solution-phase samples (ca. 6 kJ mol-1 ) than for the gas-phase species (1-3 kJ mol-1 ). The generality of the approach is demonstrated with application to tricarbonyl(η4 -norbornadiene)iron(0), Fe(NBD)(CO)3 . The temperature-dependent coalescence of the ν(CO) bands of Fe(NBD)(CO)3 is well explained by the RCM without recourse to NMR-like rapid exchange. The RCM establishes a clear link between the calculated ground and transition states of dynamic molecules and the temperature-dependence of their vibrational spectra.
- Subjects :
- 010405 organic chemistry
Norbornadiene
Organic Chemistry
Infrared spectroscopy
General Chemistry
010402 general chemistry
01 natural sciences
Catalysis
Transition state
0104 chemical sciences
Reaction coordinate
Molecular dynamics
chemistry.chemical_compound
chemistry
Computational chemistry
Ab initio quantum chemistry methods
Molecular vibration
Physical chemistry
Conformational isomerism
Subjects
Details
- ISSN :
- 09476539
- Volume :
- 22
- Database :
- OpenAIRE
- Journal :
- Chemistry - A European Journal
- Accession number :
- edsair.doi.dedup.....c2d5e69f78e4a0b61c9d1675ecda4f2d