Determination of structural parameters for ferrocenecarboxaldehyde using Fourier transform microwave spectroscopy

Area of Science:

• Organometallic Chemistry
• Molecular Spectroscopy
• Computational Chemistry

Background:

• Ferrocenecarboxaldehyde is an organometallic compound with potential applications.
• Understanding its gas-phase structure is crucial for predicting its chemical behavior and properties.

Purpose of the Study:

• To precisely determine the gas-phase structural parameters of ferrocenecarboxaldehyde.
• To investigate the conformation of the cyclopentadienyl (Cp) groups in the molecule.

Main Methods:

• Fourier transform microwave spectroscopy was employed to measure rotational transitions.
• Analysis involved fitting rotational constants of various isotopomers using a rigid rotor Hamiltonian with centrifugal distortion.
• Least-squares fit and Kraitchman analyses were performed to derive structural parameters.
• Density-functional theory (DFT) calculations aided in resolving structural ambiguities.

Main Results:

• Precise gas-phase structural parameters were determined, including Fe-C bond lengths (2.047(4) Å) and C-C distances within the Cp rings (1.430(2) Å and 1.46(1) Å).
• The analysis confirmed an eclipsed conformation for the Cp groups in the ground vibrational state.
• DFT calculations provided valuable complementary data and assisted in the structural analysis.

Conclusions:

• The gas-phase structure of ferrocenecarboxaldehyde has been accurately elucidated.
• The molecule adopts an eclipsed conformation in its ground vibrational state.
• The combination of experimental spectroscopy and theoretical calculations provides a robust structural determination.