Investigation of Infrared Spectroscopy and Raman Spectroscopy for Functional Group Identification and Structural Confirmation of Trisubstituted Benzaldehyde

Background
Vibrational spectroscopy gives organic molecules unique identifying marks on their structures (Schrader, 1995). The infrared bands become apparent by measuring the changes to the dipole moment of a molecule as it vibrates (Atkins & de Paula, 2002); whereas, Raman bands become apparent by measuring the changes in polarizability of a molecule as it vibrates (Albrecht, 1961).
Objective
The IR and Raman spectra are employed to describe the 2-hydroxy-3,4- dimethoxy-benzaldehyde, identifying functional groups and ensuring that the structure is correct (Silverstein et al., 2016).
Methods
IR-band assignments are based on established group-frequency correlations as well as region references (Banwell, 1966), while Raman-mode assignments are based on aromatic skeletal markers and substituent markers. (Schrader, 1995). All the band-mode assignments were verified using bond-strength and force-constant relationships (Badger, 1934).
Results
Raman and IR spectroscopy confirm an O-H group (phenolic), C=O carbonyl (aldehyde), and C-O bond (methoxy) presence in this sample (Silverstein et al., 2016). Strong C=C and ring breathing vibrational features were observed with Raman spectrometry (Schrader, 1995). Bands observed by IR and Raman spectroscopy correlated with one another (Banwell & McCash, 1994).
Comparison with Literature
The location of bands corresponds well with the range of frequencies for aromatic aldehydes and substituted phenyls reported (Silverstein et al., 2016), indicating that minor shifts in band positions may be attributable to Hydrogen Bonding/Substitution (Badger, 1934). A recent publication indicates that much improved analysis of spectral information can now be completed through an application of current Spectroscopic methods (Darmawan et al, 2025; Wang et al., 2025).
CONCLUSION
The combination of IR and Raman Spectroscopy represents a definitive means for characterizing the tested compound (Schrader 1995), and the data presented here will allow for further computer-generated modelling and comparative analysis of Vibrational Spectroscopy (Henschel et al., 2020).

Infrared spectroscopy; Raman spectroscopy; Vibrational assignment; Aromatic aldehyde; Methoxy substitution; Phenolic O–H

1. Albrecht, A. C. (1961). On the theory of Raman intensities. The Journal of Chemical Physics, 34(5), 1476– 1484. https://doi.org/10.1063/1.1701032 [Google Scholar] [Crossref]

2. Atkins, P., & de Paula, J. (2002). Physical chemistry (7th ed.). W. H. Freeman. [Google Scholar] [Crossref]

3. Badger, R. (1934). A relation between internuclear distances and bond force constants. The Journal of Chemical Physics, 2(3), 128. https://doi.org/10.1063/1.1749433 [Google Scholar] [Crossref]

4. Banwell, C. N. (1966). Fundamentals of molecular spectroscopy. McGraw-Hill. [Google Scholar] [Crossref]

5. Banwell, C. N., & McCash, E. M. (1994). Fundamentals of molecular spectroscopy (4th ed.). McGraw–Hill. [Google Scholar] [Crossref]

6. Darmawan, Y. A., Yanagishima, T., Fuji, T., & Kudo, T. (2025). Proposed method for label-free separation and infrared spectroscopy of carbonyl-containing micro- and nanoparticles using mid-infrared optical force. Analytical Chemistry, 97(27), 14658–14665. [Google Scholar] [Crossref]

7. https://doi.org/10.1021/acs.analchem.5c02185 [Google Scholar] [Crossref]

8. Gastegger, M., Schütt, K. T., & Müller, K.-R. (2021). Machine learning of solvent effects on molecular spectra and reactions. Chemical Science, 12(34), 11473–11483. https://doi.org/10.1039/D1SC02742E [Google Scholar] [Crossref]

9. Harwood, L. M., & Moody, C. J. (1989). Experimental organic chemistry: Principles and practice. WileyBlackwell. [Google Scholar] [Crossref]

10. Henschel, H., Andersson, A. T., Jespers, W., Ghahremanpour, M. M., & van der Spoel, D. (2020). Theoretical infrared spectra: Quantitative similarity measures and force fields. Journal of Chemical Theory and Computation, 16(5), 3307–3315. https://doi.org/10.1021/acs.jctc.0c00126 [Google Scholar] [Crossref]

11. Hu, T., Zou, Z., Li, B., Zhu, T., Gu, S., Jiang, J., Luo, Y., & Hu, W. (2025). Deep learning for bidirectional translation between molecular structures and vibrational spectra. Journal of the American Chemical Society, 147(31), 27525–27536. https://doi.org/10.1021/jacs.5c05010 [Google Scholar] [Crossref]

12. Schrader, B. (1995). Infrared and Raman spectroscopy: Methods and applications. VCH. [Google Scholar] [Crossref]

13. Silverstein, R. M., Webster, F. X., Kiemle, D. J., & Bryce, D. L. (2016). Spectrometric identification of organic compounds (8th ed.). Wiley. [Google Scholar] [Crossref]

14. Skoog, D. A., Holler, F. J., & Crouch, S. R. (2007). Principles of instrumental analysis (6th ed.). Thomson Brooks/Cole. [Google Scholar] [Crossref]

15. Wang, T., Jiang, Y., Feng, H., Liu, L., Deng, Q., Liu, D., & Wang, C. (2025). Recent advances in Raman spectroscopy for resolving material surfaces/interfaces. Catalysts,15(12),1131. [Google Scholar] [Crossref]

16. https://doi.org/10.3390/catal15121131 [Google Scholar] [Crossref]

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