What absorbs at 1141 cm⁻¹ in an FTIR spectrum?
A band near 1141 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 1141 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 |
|---|---|---|---|
| C-O single bond | 8 | 8 | 1.0 |
| Methoxy (OCH3) | 6 | 6 | 1.0 |
| Methacrylate | 6 | 6 | 1.0 |
| Acetate | 6 | 6 | 1.0 |
| Alkyl C-H | 5 | 4 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| N h | 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 |
|---|---|---|---|
| PVA | 1141, 1660, 2930 | Acetate, Methacrylate, C-O single bond | 1 |
| polypyrrole | 1141, 1700, 400 | Methacrylate, Acetate | 1 |
| polyvinyl alcohol | 1141, 1640, 1537 | Methacrylate, Acetate | 1 |
| PEG | 1141, 1650, 1342 | Methacrylate, Acetate, C-O single bond | 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 1141 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
“The strongest peak appears at 1141 which arise from the stretching cm-1 cm-1 vibration of C═N from quinoid ring protonated.”
International Conference on Innovation on Polymer Science and Technology DOI: 10.1088/1757-899X/223/1/012051 -
N h confidence 1.0
“The three sericin-PVA showed weak to aldehyde group with OH groups of the PVA chain medium, broad hydrogen-bonded bands that result from the or possibly the contribution of the remaining acetate groups of structure.23 overlap of free and bo”
Manesa 等 - 2022 - Fabrication and Characterization of Sericin-PVA Co DOI: 10.1021/acsomega.2c00897 -
Alkyl C-H confidence 1.0
“The band at 1141 is attrib(cid:2) group in uted to the C-H bending vibration of -CH The FTIR spectra of the thermally polymerized”
Surender 等 - 2014 - Bismaleimide and Bispropargyl Ether Blends Curing DOI: 10.1134/S1560090414050157 -
Acetate confidence 1.0
“While the peak at 1141 indicates the stretching of C-O cm-1 from the crystalline sequence of PVA, the peak at 1073 indicated the stretching of C-O from the amorphous sequence of PVA [23].”
Poly(vinyl alcohol) Nanocomposites Reinforced with Bamboo Charcoal Nanoparticles: Mineralization Behavior and Characterization DOI: 10.3390/ma8084895 -
Alkyl C-H confidence 1.0
“temperature is lower than 45 °C, which is attributed to the cm-1 C-H An important absorbance peak at 1141 is usually minor influence of the diffused water on the bonds.”
Xue 等 - 2015 - Moving-window two-dimensional correlation infrared DOI: 10.1007/s00216-015-9035-1 -
C-O single bond confidence 1.0
“but when sodium alginate was present in large quantities and was highly concentrated, three peaks that express the functional group's formula appeared, with absorption ranges cm-1 cm-1 of 1141 and 1268 due to the extended vibration of the C”
ALSamman 和 Sanchez - 2023 - Adsorption of Copper and Arsenic from Water Using DOI: 10.3390/polym15092192 -
Acetate confidence 1.0
“Finally, the bands at 1141 and 843 water, glycerol and diiodomethane on the PU As are due C-O-C expected, the hydrophilicity of the substrata increased with to the asymmetric and symmetric vibrations, PEG grafting density as shown by the wa”
Effect of PEG grafting density on surface properties of polyurethane substrata and the viability of osteoblast and fibroblast cells DOI: 10.1007/s10856-022-06668-1 -
N-O bond confidence 1.0
“Fe-O vibrational 1003cm-1 modes in FeOOH were ascribed at 1640, 1363, and for the PPy NPs peak at due to the out-of-plane 1141cm-1 in the PFFs spectra while there were no peaks in bending C-H bond [31, 34-36].”
Diauudin 等 - 2020 - Preparation and Characterisation of Polypyrrole-Ir DOI: 10.1155/2020/8762969
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