FT-IR spectroscopy and DFT calculation study on the solvent effects of benzaldehyde in organic solvents

FT-IR spectra of benzaldehyde in 11 different organic solvents were recorded and analyzed. The density functional theory (DFT) B3LYP/6-31G* method was chosen to calculate the infrared spectrum of benzaldehyde in gaseous state. The electrostatic effects of different solvents in benzaldehyde solutions were calculated using DFT with the self-consistent isodensity polarizable continuum model (SCI-PCM). Two remarkable carbonyl (CO) peaks of benzaldehyde were observed by FT-IR in alcohol solvents, which were caused by different hydrogen bond species and explained by ab initio calculation. The results showed that the combination of SCI-PCM model and ab initio calculation could give excellent agreements with FT-IR spectra of title compound in solutions.

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► B3LYP/6-31G* is the optimum method and basic set to calculate νCO of benzaldehyde.
► SCI-PCM model and parameter G describe non-specific interaction in solutions.
► Ab initio calculations simulate the hydrogen bonds in alcohol solution.
► This method provides a new way to study solvent effects.