Structure and vibrational assignment of beryllium acetylacetonate

Area of Science:

• Computational Chemistry
• Molecular Spectroscopy
• Inorganic Chemistry

Background:

• Beryllium acetylacetonate (Be(acac)2) is a key organometallic compound.
• Understanding its vibrational properties is crucial for characterizing its structure and bonding.
• Previous studies may lack detailed computational analysis of its vibrational spectra.

Purpose of the Study:

• To perform a comprehensive structural optimization of Be(acac)2 using various computational levels.
• To calculate and assign vibrational frequencies for Be(acac)2 and its isotopically substituted derivatives.
• To compare theoretical vibrational spectra with experimental Fourier transform IR and Raman data.

Main Methods:

• Density Functional Theory (DFT) calculations using B3LYP functional with multiple basis sets (6-31G*, 6-311G*, 6-311++G(3df,2p)).
• Hartree-Fock and Möller-Plesset perturbation theory calculations.
• Calculation of vibrational frequencies and intensities, including anharmonic frequencies.
• Isotopic substitution studies (13C, 2H, 18O) to aid spectral assignment.

Main Results:

• Optimized structural parameters show excellent agreement with experimental data.
• Calculated vibrational frequencies closely match experimental Fourier transform IR and Raman spectra.
• Strong coupling between chelated ring modes was identified.
• Four distinct bands attributed to metal-oxygen stretching motions were identified at 1042, 826, 748, and 480 cm(-1).

Conclusions:

• The theoretical calculations accurately predict the vibrational spectra of Be(acac)2.
• The study provides a detailed assignment of vibrational modes, enhancing the understanding of Be(acac)2 structure and bonding.
• The identified metal-oxygen stretching bands offer specific insights into the coordination environment of beryllium.