What absorbs at 1231 cm⁻¹ in an FTIR spectrum?
A band near 1231 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
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Amide | 3 | 3 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Phosphorus | 2 | 1 | 1.0 |
| Phosphate (PO4) | 2 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Alkyl C-H confidence 1.0
“There is an intermolecular force between the benzene ring of PANI and RGO sheet, therefore, the intensity of ACCEPTED MANUSCRIPT cm-1 cm-1 C-H C-C peaks of the bending of the benzenoid ring at 1231 and the stretching of the benzene ring at”
Highly conductive and flexible silk fabric via electrostatic self assemble between reduced graphene oxide and polyaniline DOI: 10.1016/j.orgel.2017.12.016 -
confidence 1.0
“1267 O-C-O and Guaiacyl ring Stretching vibration in lignin and xylan 1231 1234 O-C-O and Syringyl ring Stretching vibration in lignin and xylan 1513 1508 Aromatic skeletal vibrations in extractives and lignin 1205”
Jin 等 - 2022 - Rapid Identification for the Pterocarpus Bracelet DOI: 10.3390/molecules27154793 -
Phosphate (PO4) confidence 1.0
“Similarly, in the cm-1 three groups, an increase in the 1231 band originating from the P=O bond stretching cm-1 vibration in the phosphate groups was observed.”
Synergistic Antifungal Interactions between Antibiotic Amphotericin B and Selected 1,3,4-thiadiazole Derivatives, Determined by Microbiological, Cytochemical, and Molecular Spectroscopic Studies DOI: 10.3390/ijms24043430 -
Acetate confidence 1.0
“1687cm-1, C=O the positive band at nation bands are originated from stretch of and the positive band at 10cm-1 1246cm-1 1231cm-1.”
Vibrational spectroscopy analysis of ligand efficacy in human M2 muscarinic acetylcholine receptor (M2R) DOI: 10.1038/s42003-021-02836-1 -
Amide confidence 1.0
“Similar findings were obtained for vibrational modes associated with the cm-1 amide III band from proteins, which illustrates a band peaking at 1231 in unlabeled cm-1 13C14N13C15N-labeled bacteria, 1228 and 1211 in and samples [4].”
Simultaneous Raman and Infrared Spectroscopy of Stable Isotope Labelled Escherichia coli DOI: 10.3390/s22103928 -
C c single bond confidence 1.0
“1420 corresponded to C-C stretching vibration in the cm-1 at1231cm-1 An absorption band at around 3580 is attributed to benzenering.An absorption band isduetoC-C”
Nabipour 和 Sadr - 2015 - Layered zinc hydroxide-ibuprofen nanohybrids synt DOI: 10.1080/17458080.2014.998301 -
N h confidence 1.0
“region of 1051 to 1025 C X (where X = Cl, Br, and dance with the literature and proposed structure of quinderivatives.[77-80] All compounds showed two peaks F F) also observed in their respective region, that is, C oline cm-1 stretching vib”
Development of an Efficient, One-Pot, Multicomponent Protocol for Synthesis of 8-Hydroxy-4-Phenyl-1,2-Dihydroquinoline Derivatives DOI: 10.1002/jhet.4193 -
Amide confidence 1.0
“The presence of BSA within the sample is cm-1, 447 confirmed by the C-N stretch present at 1231 as has previously been seen for other 448 liposomal preparations (Hui & Huang, 2021).”
Weaver 等 - 2022 - Microfluidic-mediated self-assembly of phospholipi DOI: 10.1016/j.ijpharm.2021.121347
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