What absorbs at 1398 cm⁻¹ in an FTIR spectrum?
A band near 1398 cm⁻¹ can point to several functional groups. Below are the most likely assignments, ranked by how much published evidence supports each — every one traceable to literature (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 8 cited sources
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Alkyl C-H | 8 | 8 | 1.0 |
| Amide | 6 | 6 | 1.0 |
| Methacrylate | 5 | 5 | 1.0 |
| Acetate | 5 | 5 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Carbonyl (C=O) | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Secondary amine | 3 | 3 | 1.0 |
| C n single bond | 3 | 3 | 1.0 |
| Protein | 2 | 2 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Methyl | 2 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Protein beta sheet | 1 | 1 | 1.0 |
| Lipid | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Sulfur heterocycle | 1 | 1 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 0.9 |
| C=n | 1 | 1 | 0.9 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
C-S single bond confidence 1.0
“After polymerization of the aniline moiety, sharp of cm-1 peaks representing C N and C S appeared at 1398 and 617 stretching vibrations, respectively.”
Stopband attenuation of silica spheres by attaching aniline and polyaniline DOI: 10.1016/j.synthmet.2013.03.007 -
Amide confidence 1.0
“The band III represents the vibrations in 1000 to 2000 cm-1 cm-1 is attributed to C N [16, 17] and the peak at 1398 absorption peak at 1591 cm-1 C-C of sp3 corresponds to amorphous bonds [18].”
Ramesh 等 - 2010 - Synthesis of Nano Structured Carbon Nitride by Pyr DOI: 10.1080/10584587.2010.489421 -
Sulfur heterocycle confidence 1.0
“Synthesis of PMOT/NiO nanocomposite The band thiophene ring were found at 1576 and 1398 cm-1 at 1092 has been identified as the stretching vibration of”
Sehgal 和 Narula - 2015 - Structural, morphological, optical, and electrical DOI: 10.1007/s00396-015-3663-z -
Alkyl C-H confidence 1.0
“cm-1 1157 were assigned to the C-H bending vibration of collagen peptide and asymmetric stretching The peaks around 1398 cm-1 and 1157 cm-1 were assigned to the C-H bending vibration of collagen”
Sponges of Carboxymethyl Chitosan Grafted with Collagen Peptides for Wound Healing DOI: 10.3390/ijms20163890 -
Alkyl C-H confidence 1.0
“95 92 C-H stretching Alkyne ** 1398 99 95 90 O-Hbending Carboxylicacid 1543 99 94”
A Comparison of Water Imbibition and Controlled Deterioration in Five Orthodox Species DOI: 10.3390/agronomy12071486 -
Lipid confidence 1.0
“This was based on PC-2, which was driven by differences in the 1740 1 lipid peak, the relative enrichment of β-sheets in the DJX species, and differences in the width cm-1 of the 1398 peak.”
Synchrotron FTIR as a tool for studying populations and individual living cells of green algae DOI: 10.1101/808220 -
Alkyl C-H confidence 1.0
“cm-1, the aromatic C=C bond is tenuously situated at 1602 and 1491 At 1398 cm-1, there is a corresponding deformed CH and CH absorption band.”
Valoration of the Synthetic Antioxidant Tris-(Diterbutyl-Phenol)-Phosphite (Irgafos P-168) from Industrial Wastewater and Application in Polypropylene Matrices to Minimize Its Thermal Degradation DOI: 10.3390/molecules28073163 -
Amide confidence 1.0
“The cm-1, cm-1 cm-1 peaks entered at 1398 1025 and 661 can be associated with C-N stretching of amine, alcohol/phenolic stretching, and aromatic C-H bending (Manikandan et al.”
Application of mycogenic silver/silver oxide nanoparticles in electrochemical glucose sensing; alongside their catalytic and antimicrobial activity DOI: 10.1007/s13205-021-02888-4
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