Vibrational spectroscopy and density functional theory study of ninhydrin

•Most of the fundamentals vibrations agree well with the predicted frequencies.•Hydrogen bond donors and acceptors are predicted.•The vibrational spectra of ninhydrin SERS are investigated experimentally and theoretically.

In this paper, ninhydrin was designed as a model molecule for theoretical and experimental studies of the molecule structure. Density functional theory (DFT) calculations have been performed to predict the IR and Raman spectra for the molecule. In addition, Fourier transform infrared (FTIR) and Raman spectra of the compound have been obtained experimentally. Based on the modeling results obtained at the B3LYP/6-311++G** level, all FTIR and Raman bands of the compound obtained experimentally were assigned. Our calculated vibrational frequencies are in good agreement with the experimental values. The molecular electrostatic potential surface calculation was performed and the result suggested that the ninhydrin had two potential hydrogen bond donors and four potential hydrogen bond acceptors. HOMO–LUMO gap was also obtained theoretically at B3LYP/6-311++G** level.

Graphical abstractNinhydrin was designed as a model molecule for theoretical and experimental studies of the molecule structure. Fourier transform infrared (FTIR) and Raman spectra of the compound have been obtained experimentally. Most of the fundamentals vibrations agree well with the predicted frequencies.Figure optionsDownload full-size imageDownload as PowerPoint slide