What absorbs at 1277 cm⁻¹ in an FTIR spectrum?
A band near 1277 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 1277 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 |
|---|---|---|---|
| Methacrylate | 6 | 6 | 1.0 |
| Acetate | 6 | 6 | 1.0 |
| Methoxy (OCH3) | 5 | 5 | 1.0 |
| C-O single bond | 5 | 5 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Secondary amine | 5 | 5 | 1.0 |
| C n single bond | 4 | 4 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Protein alpha helix | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 0.9 |
| Sulfonate | 1 | 0 | 1.0 |
| Bromine | 1 | 0 | 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 |
|---|---|---|---|
| polyvinylpyrrolidone | 1277, 1660, 1700 | Methacrylate, Acetate | 1 |
| PVP | 1277, 2983, 1648 | Methacrylate, Acetate | 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 1277 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
-
Amide confidence 1.0
“NFs synthesized at 60 are cm-1 C-N band at 1277 can be assigned to the stretching found to be thinner and broader in size according to the”
Performance of Polyaniline Nanofibers (PANI NFs) as PANI NFs-Silver (Ag) Nanocomposites (NCs) for Energy Storage and Antibacterial Applications DOI: 10.1021/acsomega.8b02834 -
C c single bond confidence 1.0
“., , -1 -1 cm (C-N stretch) and 1276.88 cm (C-C, C-H, O-H stretch).”
Maity 等 - 2017 - Polyhydroxyalkanoates production by Zobellella spe DOI: 10.22438/jeb/38/6/MRN-533 -
Acetate confidence 1.0
“wagging at 1335 The peaks at 1277 and 1159 are ascribed cm(cid:0) 1 C-O-C An aliquot of the wine samples (6 mL) was passed through the carto the stretching of the ether bonds in cycles.”
Characterization of the medium infrared spectra of polyphenols of red and white wines by integrating FT IR and UV–Vis spectral data DOI: 10.1016/j.lwt.2021.111604 -
Amide confidence 1.0
“1316 Strong C-N stretching Aromatic amine 1277 Strong”
Evaluation of anticandidal activities and phytochemical examination of extracts prepared from DOI: 10.1186/s12906-022-03552-x -
Amide confidence 1.0
“The band cm-1 observed at 1277 is associated with C-N stretching, cm-1, and the two distinct bands occur at 838 and cm-1 639 related to the C-C ring and C-N=O bending,”
Alibe 等 - 2019 - Effects of polyvinylpyrrolidone on structural and DOI: 10.1007/s10973-018-7874-7 -
Aromatic ring confidence 1.0
“The band at 1650 cm-1 has been assigned to the carbonyl stretching vibration, a number of skeletal ring vibrations at 1598, 1490 and 1413 cm-1, the asymmetric stretching of ether group at 1277 and 1190 cm-1, the aromatic hydrogen in-plane d”
Mechano-Chemical Properties of Electron Beam Irradiated Polyetheretherketone DOI: 10.3390/polym14153067 -
Acetate confidence 1.0
“CP presented a characteristic peak at 2976 cm-1 cm-1 cm-1 2976 (C-H stretching vibration), the peak at 1622 was due to the C=O stretching (C-H stretching vibration), the peak at 1622 cm-1 was due to the C=O stretching and 1277 cm-1 cm-1 and”
Almotairi 等 - 2022 - Design and Optimization of Lornoxicam Dispersible DOI: 10.3390/ph15121463 -
Hydroxyl (O-H) confidence 1.0
“The intense band at 1277 is attributed to (CO) asym vibration due to the deprotonated species derived from the hydroxyl group.”
Chavan 等 - 2013 - Fundamental Aspects of H2S Adsorption on CPO-27-Ni DOI: 10.1021/jp402440u
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