What absorbs at 1293 cm⁻¹ in an FTIR spectrum?
A band near 1293 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
Quick answer
A band near 1293 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Methoxy (OCH3) | 4 | 4 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| C-O single bond | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| N h | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| PLA | 1293, 1650, 1073 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
| PCL | 1293, 1751, 1724 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
| CuO | 1293, 453, 1000 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 1293 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
Literature behind these assignments
-
Aromatic ring confidence 1.0
“PANi/PPy/PTh displayed typical aromatic C-H stretching vibration was found at 1293 Due to the incorporation 419 R.”
Ashraf 等 - 2014 - Preparation and properties of multilayered polymer DOI: 10.1515/polyeng-2013-0297 -
Hydroxyl (O-H) confidence 1.0
“(cid:2) FC stretch 1293sh 1282 (0.20) CO phenolic stretch 1275 1277 (0.99)”
Hydrogen Bonding in Human Manganese Superoxide Dismutase Containing 3-Fluorotyrosine DOI: 10.1529/biophysj.105.060616 -
Secondary amine confidence 1.0
“stretching mode of the secondary amine (C-N-C) [32] or imine (-N=) at 1293 cm-1 [33], to FTIR spectroscopy was conducted on the PAni, PAni-SnCl 2, PAni-PEDOT:PSS (3 wt%), the stretching vibration in the polaron structure (C-N+ or C=N+) at 1”
Conductive Polymer Composites for Hydrogen Sulphide Sensors Working at Sub-PPM Level and Room Temperature DOI: 10.3390/s21196529 -
C-O single bond confidence 1.0
“The band at 1293 cm-1 can be assigned to ν(C-O) and ν(C-C)”
Hydrolytic Degradation of Porous Crosslinked Poly(-Caprolactone) Synthesized by High Internal Phase Emulsion Templating DOI: 10.3390/polym12081849 -
Acetate confidence 1.0
“The bands at 1394 cm-1 corresponding to catechol C-O-H, and broad and 1293 cm-1 band at around 3300-3400 of O-H and N-H were found to be decreased, suggesting the expected chemical change upon Figure 4.”
Jeon 等 - 2014 - Oxidative Gelation of Dopamine-modified Polyaspart DOI: 10.7317/pk.2014.38.1.108 -
C c single bond confidence 1.0
“LLM confirmed rule peak-group candidate”
Jeon 等 - 2018 - Improvements in the Rheological Properties, Impact DOI: 10.1155/2018/5316175 -
Alkyl C-H confidence 1.0
“cm-1 cm-1 absorption bands at ~ 1293 and ~ 1122 reveal with better cohesion and higher aggregation than what is the presence of the C-H bending vibrations [27, 28].”
Mokole 等 - 2023 - Electrochemical detection of dopamine using green DOI: 10.1007/s00339-023-06438-y -
confidence 1.0
“The MSN-Cip spectrum exhibits new at 1550 and 1293 cm-1 for the N-H in-plane bend and C-N stretching, respectively [43].”
Boosting Antimicrobial Activity of Ciprofloxacin by Functionalization of Mesoporous Silica Nanoparticles DOI: 10.3390/pharmaceutics13020218
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