What absorbs at 1539 cm⁻¹ in an FTIR spectrum?
A band near 1539 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 1539 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 |
|---|---|---|---|
| Amide | 15 | 15 | 1.0 |
| N h | 8 | 7 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Secondary amine | 3 | 2 | 1.0 |
| C n single bond | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| C=n | 2 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Bromine | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Acetyl | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 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 |
|---|---|---|---|
| polysaccharides | 1539, 1053, 1143 | Alkyl C-H, Amide | 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 1539 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
-
Carbonyl (C=O) confidence 1.0
“cm-1 229 depicts stretching of C-H bonds of heterocyclic compounds, strong bands at 1650 & 1700 cm-1 cm-1 230 corresponds to carbonyl group (C=O) of amide-I and band at 1539 corresponds to 10”
Microencapsulation of caffeine loaded in polysaccharide based delivery systems DOI: 10.1016/j.foodhyd.2018.04.001 -
confidence 1.0
“cm-1 metric bending of NH the bands about 1539 are related to N-H bending or symmetric bend4+.”
Parfenyuk 等 - 2018 - SURFACE PROPERTIES OF TITANIUM ALLOY VT 6 AFTER PL DOI: 10.6060/tcct.20186103.5705 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Structural analysis of some soluble elastins by means of FTIR and 2D IR correlation spectroscopy DOI: 10.1002/bip.21524 -
confidence 1.0
“cm21 find that the development of terminal diene and The peak at 1539 is due to zinc stearate and”
Effects of hot-air aging and dynamic fatigue on the structure and dynamic viscoelastic properties of unfilled natural rubber vulcanizates DOI: 10.1002/app.27216 -
Alkyl C-H confidence 1.0
“cm(cid:1)1 cm(cid:1)1 1378 The 1462 1462 and 1473 and those used in peak is assigned to a bending (scissoring) cm(cid:1)1, a recent SNOM study of a single cancerous cell, 1242 vibration of methylene (CH 2) groups in general and many biocm(c”
Al Jedani 等 - 2020 - A de-waxing methodology for scanning probe microsc DOI: 10.1039/d0ay00965b -
confidence 1.0
“The two medium bands at 1539 cm-1 were assigned to the pyridine skeletal stretching -2.7 formation of the desired product are the broad signal to ppm associated with the NH and two medium bands at 1539 cm-1 and 1473 cm-1 correspond to C=C a”
Synthesis of a New Co Metal–Organic Framework Assembled from 5,10,15,20-Tetrakis((pyridin-4-yl) phenyl)porphyrin “Co-MTPhPyP” and Its Application to the Removal of Heavy Metal Ions DOI: 10.3390/molecules28041816 -
Amide confidence 1.0
“The amide II band cm-1 at 1539 is due to vibrational modes involving the C-N-H bending and C-N stretching of the”
Synthesis of Bioactive Chlorogenic Acid-Silica Hybrid Materials via the Sol–Gel Route and Evaluation of Their Biocompatibility DOI: 10.3390/ma10070840 -
Acetate confidence 1.0
“The band at 1539 cm-1 is cm´1 is attributed to C-O stretching of the acetyl group (amide I).”
Preparation and Characterization of Polyvinyl Alcohol-Chitosan Composite Films Reinforced with Cellulose Nanofiber DOI: 10.3390/ma9080644
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