What absorbs at 1243 cm⁻¹ in an FTIR spectrum?
A band near 1243 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 1243 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.
可能性のある官能基アサイン
| 官能基 | 裏付け事実 | 引用元 | 最高信頼度 |
|---|---|---|---|
| C-O single bond | 12 | 12 | 1.0 |
| Methoxy (OCH3) | 11 | 11 | 1.0 |
| Methacrylate | 11 | 11 | 1.0 |
| Acetate | 11 | 11 | 1.0 |
| Amide | 7 | 7 | 1.0 |
| Alkyl C-H | 6 | 6 | 1.0 |
| Secondary amine | 5 | 5 | 1.0 |
| C n single bond | 4 | 4 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Phosphate (PO4) | 3 | 3 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Phospholipid | 1 | 1 | 0.9 |
| Fluorine (C-F) | 1 | 1 | 0.7 |
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Possible materials
| 素材 | 補助ピーク | Overlapping groups | 引用元 |
|---|---|---|---|
| Cellulose | 1243, 1735, 1650 | Acetate, Methacrylate, C-O single bond | 1 |
| asphalt binder | 1243, 1700, 1242 | 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 1243 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.
これらのアサインの根拠となる文献
-
Alkyl C-H 信頼度 1.0
“shoulder band at about The 1459 and 1384cm-1 bands are methyl bending signals and bands at 1243”
Font 等 - 2007 - Fourier transform infrared spectroscopy as a suita DOI: 10.1016/j.aca.2007.07.021 -
Acetate 信頼度 1.0
“The peak at wavelength The ratio of cellulose to concentration as a EFB AA cm-1 1243 is attributed to the stretching of and C-O C=O modified reagent played a significant role on the WPG deformation of the ester bond.”
Jahi 等 - 2020 - Empty Fruit Bunch Cellulose based Sorbent for Oil DOI: 10.17576/jsm-2020-4909-29 -
Alkyl C-H 信頼度 1.0
“(690-900 C-O (970-1250 and stretching A peak at cm-1 C-H 1243.26 may be assigned to bonding.”
Synthesis and characterization of a green‐light‐emitting (pbi‐Br)2Ir (acac) metal complex for OLEDs DOI: 10.1002/bio.3565 -
Acetate 信頼度 1.0
“However, peak at cm-1 1243 was absence upon acid hydrolysis due to the removal of C-O-C functional group of aryl-alkyl ether in 460 lignin [17].”
Kuthi 和 Badri - 2014 - Effect of Cooking Temperature on the Crystallinity DOI: 10.1063/1.4895240 -
Alkyl C-H 信頼度 1.0
“Related studies have confirmed that when EVA is added to a modified asphalt is peak-responsive in wavenumber of 1243 and 1740 by the combination of cm(cid:2879)(cid:2869) cm(cid:2879)(cid:2869) binder, it is peak-responsive in wavenumber of”
Analysis of the Properties of Modified Asphalt Binder by FTIR Method DOI: 10.3390/ma15165743 -
Amide 信頼度 1.0
“FTIR spectra Implants of FIB and HA-FIB films exhibited distinctive absorption maxima, in specific positions of FIB random MatrixAssistedPulsedLaserEvaporation 1540cm-1 1654cm-1 1243cm-1 1027cm-1 (MAPLE) coil form: amide II, amide I, amide”
Composite biocompatible hydroxyapatite⠍silk fibroin coatings for medical implants obtained by Matrix Assisted Pulsed Laser Evaporation DOI: 10.1016/j.mseb.2009.10.004 -
C-O single bond 信頼度 1.0
“and multiple CF band (1243, 1190, 800,and 748 From Figure 2 shows asymmetric stretching mode of ether funcFig.”
Radzir 等 - 2015 - Effect of lithium bis(trifluoromethylsulfonyl)imid DOI: 10.1007/s10008-015-2910-z -
Amide 信頼度 1.0
“purine = √ D L(cid:4)H (6) A0˛,A(cid:4)L(cid:4)˛(cid:4) A(cid:4)˛(cid:4) (cid:3) A˛, m Am cm-1 A(cid:4) The vibration at 1243 comes from the in-plane stretching of the C N bonds and the stretching and in-plane swinging of where”
A comparative study on the experimental and calculated results of mid-infrared and Raman vibrational modes of nucleic acid bases DOI: 10.1016/j.jmgm.2017.04.016
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