What absorbs at 3249 cm⁻¹ in an FTIR spectrum?
A band near 3249 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 5 cited sources
Quick answer
A band near 3249 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.
Возможные назначения функциональных групп
| Функциональная группа | Подтверждающие факты | Цитируемые источники | Максимальная достоверность |
|---|---|---|---|
| Hydroxyl (O-H) | 3 | 3 | 1,0 |
| Secondary amine | 2 | 2 | 1,0 |
| N h | 2 | 2 | 1,0 |
Ранжирование отражает накопленные литературные данные, а не единственное авторитетное правило. Всегда проверяйте в контексте вашего образца.
Possible materials
| Материал | Поддерживающие пики | Overlapping groups | Цитируемые источники |
|---|---|---|---|
| PVA | 3249, 1660, 2930 | Hydroxyl (O-H) | 1 |
| water | 3249, 1018, 2945 | Hydroxyl (O-H) | 1 |
| silver nanoparticles | 3249, 1636, 1631 | Hydroxyl (O-H), N h | 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 3249 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.
Литература, лежащая в основе этих назначений
-
достоверность 1,0
“cm-1 cm-1 broadened and shifted to 3410 with single broad band is observed at 3249 originating from the stretching vibrations of the -N-H group of secondary amine as illustrated in the scheme 1.”
Haniffa 等 - 2019 - Synergistic effect of (3-Aminopropyl)Trimethoxysil DOI: 10.1016/j.polymdegradstab.2018.11.009 -
Hydroxyl (O-H) достоверность 1,0
“- - 1138 O-H Stretching Alcohol - 3249”
Eco-Friendly Fire-Resistant Coatings Containing Dihydrogen Ammonium Phosphate Microcapsules and Tannins DOI: 10.3390/coatings11030280 -
Hydroxyl (O-H) достоверность 1,0
“3267 2887 1590 1406 1229 1009 , , and The absorption bands at 1367 3249cm-1 3600 3000 2400 1800 1200 600 in the FTIR spectra were due to O-H stretching (cm-1 2895cm-1 ) vibration of alcohol and phenol.”
Jemal 等 - 2017 - Synthesis, Characterization, and Evaluation of the DOI: 10.1155/2017/4213275 -
N h достоверность 1,0
“cm(cid:2)1): Lightyellowsolid,Yield:95%,m.p:235-237(cid:4)C,Rf:0.69(Acetone:n3478.58, 3432.99, 3385.93, hexane (7:3)), FTIR (KBr disc, cm(cid:2)1): (C(cid:3)N), (NH2, NH stretch), 3248.52 (Ar CH), 2189.38 1643.38 3339.23 3427.77, 3351.30 (N”
7-Hydroxy-4-phenyl-1, 2-dihydroquinoline derivatives: synthesis via one-pot, three-component reaction and structure elucidation DOI: 10.1016/j.heliyon.2020.e05035 -
Hydroxyl (O-H) достоверность 0,7
“Deconvolution peak in OH stretching region.”
Munoz 等 - 2007 - FTIR study of water clusters in water-triethylamin DOI: 10.1016/j.chemphys.2007.03.015
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